ISSN Electrónico 2395 - 8030.
Evaluation of Vulcanized Rubber Consumption by Lignocellulolytic Fungi
The biodegradation of vulcanized rubber is an environmental challenge due to its high resistance to decomposition. This study evaluated the ability of three lignocellulolytic fungal strains (Phlebiopsis sp., Trametes sanguinea, and Trametes cingulata) to degrade tire powder in a liquid medium, selecting these strains for their prior ability to degrade toxic compounds such as xylene. The results highlighted Phlebiopsis sp. as the most ef fective strain, with a notable 43.163% reduction in rubber content in the treatment with 75% rubber and 25% PDB (T2). T. sanguinea also showed significant performance, with a 9.58% reduction in the same treatment. These results underscore the potential of these strains for rubber bioremediation, a material known for its environmental persistence. FTIR spectroscopy confirmed that both Phlebiopsis sp. and T. sanguinea caused structural modifications in the rubber, showing a decrease in signals associated with the functional groups of rubber and carbon black. This demonstrates that these fungi can alter the chemical structure of rubber, facilitating its degradation. This study highlights the importance of selecting specific strains for industrial bioremediation. Phlebiopsis sp. emerges as an up-and-coming option due to its high degradation capacity. T. sanguinea, although less ef fective, also presents considerable potential. These findings are crucial for developing ef fective strategies for managing rubber waste and suggest that future research should focus on optimizing cultivation conditions and exploring the enzymatic mechanisms of these strains.
Copyright (c) 2025 REVISTA TERRA LATINOAMERICANA
Effect of Water Stress on Enzymatic Activity in two Strawberry Cultivars (Fragaria x ananassa)
Strawberry (Fragaria x ananassa) is a fruit produced in the central region of Mexico. This crop is af fected by unfavorable climatic conditions such as drought. The aim of this study was to evaluate the ef fect of water stress and its relationship with changes in enzym activity of the antioxidant system in the cultivars ‘Camino Real’ and ‘Cabrillo’ in the Toluca Valley. The experiment was divided into three phases: F0 (initial), F1 (drought phase) – divided into two dif ferent water regimes: a) optimal or control and b) zero regime and F2 (recovery phase), where the zero regime was subsequently re-irrigated to optimal levels. The enzymatic activities of catalase (CAT) and peroxidase (POX) were evaluated, as well as the concentrations of hydrogen peroxide (H2O2) and proline. A randomized design was established, with three replicates and 15 experimental units each one. F0 showed dif ferences in all variables between cultivars. In the zero regime (F1), compared to the control, the ‘Camino Real’ cultivar showed a 36.03% increase in POX activity and a 22.95% decrease in CAT activity, while ‘Cabrillo’ exhibited a 69.43% decrease in POX activity and a 31.26% increase in CAT activity. H2O2 and proline concentrations increased in both cultivars. In F2, no dif ferences in enzymatic activities were found between the cultivars. The determination of enzymes and osmolytes can serve as indicators of strawberry cultivars with drought stress tolerance traits in new geographical regions. It was concluded that the ‘Camino Real’ cultivar exhibited drought tolerance through enzymatic mechanisms, while the ‘Cabrillo’ cultivar demonstrated low tolerance through osmolyte accumulation mechanisms.
Adaptation of Canna sp. to the Use of Stabilized Material as Substrate in Constructed Wetlands
The advantages of constructed wetlands, such as their low cost of construction and operation, as well as the contribution of ecosystem services, give them a high potential to be used in wastewater treatment in developing countries; the search for new substrates is one of the ways to optimize these systems. In this sense, aged refuse, which are wastes from closed landfill cells, could be potentially favorable for this application since the physicochemical characteristics that have been reported for these materials can contribute to the removal of compounds present in wastewater, In addition the presence of microorganisms adapted to the assimilation of pollutants can contribute to increase the ef ficiency of the system. On the other hand, it has been demonstrated that aged refuses can contribute to plant development, which would allow the establishment of crops of commercial interest with greater requirements, such as ornamental plants. In this work, four mixtures of aged refuses and gravel (0/100 %, 25/75 %, 50/50 %, 75/25 %) were evaluated as substrate in subsurface wetlands with an ef fective operating volume of 45 liters planted with Canna sp. under a completely randomized design, which were carried out in triplicate. The results suggest that Canna sp. can develop adaptation mechanisms that allow it to survive in the operating conditions present in an artificial wetland; however, the presence and proportion of aged refuses positively influenced the plant development, significantly increasing biomass generation, flower production, and chlorophyll content; a response attributable to the nitrogen, phosphorus, and potassium content found in the aged refuses, as well as to its cation exchange capacity. However, proportions of aged refuse higher than 50 % negatively af fect the hydraulic behavior of the system.
Evaluation of the Bacterial Diversity of Composts and Vermicomposts Fed with Animal Waste. Data Analysis Based on Illumina High-Throughput Sequencing
Animal organic wastes are commonly applied to soil to enhance fertility. Still, before application, they are of ten composted or vermicomposted to produce a more stabilized, nutrient-rich product with a broad beneficial bacterial diversity. This study was aimed to investigate how composting and vermicomposting influenced the physicochemical properties and bacterial community structure of various organic wastes. Cow manure, goat and rabbit feces, and pig slurry were subjected to either composting or vermicomposting using Eisenia fetida for 90 days, during which their physicochemical characteristics and bacterial communities were monitored. Both composting and vermicomposting had similar ef fects on the physicochemical properties of the animal wastes: pH and total nitrogen (N) content increased. In contrast, electrolytic conductivity and organic carbon (C) content decreased. Although both processes altered the bacterial community structure across all operational taxonomic units (OTUs), significant dif ferences remained between the bacterial communities of the dif ferent organic wastes. Vermicomposting also reduced the prevalence of bacterial genera with pathogenic potential, such as Enterobacterand and Acinetobacter. The introduction of earthworms into organic waste had a similar ef fect to composting on the structure of the bacterial community.
Potential of Chlorophytum comosum for the Remediation of Soils Contaminated with Glyphosate
Glyphosate is a widely used herbicide, but its excessive use has raised concerns about its potential adverse ef fects on human health and the environment due to its persistence in the soil. Phytoremediation, which utilizes the ability of plants to absorb, accumulate, and metabolize contaminants, is presented as a viable and cost-ef fective alternative to remediate glyphosate-contaminated soils. Therefore, the main objective of this research was to evaluate the phytoremediation capacity of Chlorophytum comosum (spider plant) in agricultural soils contaminated with glyphosate. A greenhouse experiment was conducted by intentionally contaminating an agricultural soil with glyphosate at a concentration of 1.2 ml kg-1 of the active ingredient glyphosate. Three treatments were established: soil contaminated without plant (TSx), soil not contaminated + plant (TM), and soil contaminated + plant (TMx). Plant biometric variables and concentrations of glyphosate and aminomethylphosphonic acid (AMPA), were measured in soil and plant tissues at dif ferent times. The C. comosum plants in glyphosate-contaminated soil (TMx) showed greater growth in height and number of leaves, as well as greater biomass compared to the plants in uncontaminated soil (TM). The TMx treatment showed a significant reduction in glyphosate and AMPA concentrations in the soil af ter 180 days, reaching 100% dissipation of glyphosate. AMPA was detected in the roots of TMx plants. C. comosum plants showed a remarkable ability to adapt to and tolerate soils contaminated with glyphosate and AMPA, utilizing glyphosate-derived compounds as nutrients source and contributing to their degradation in the soil. These results suggest that C. comosum represents a promising alternative for the phytoremediation of glyphosate contaminated soils.
Ef fect of Laser Radiation in Seeds on Germination and Yield of Peanuts in the Field (Arachis hypogaea L.)
Peanut is a leguminous plant that, in addition to having positive ef fects on soil quality, provides oilseeds, which have multiple uses, because they are nutritious, medicinal, and economically important. Currently, various studies are focused on increasing the content of antioxidant compounds, as well as improving the productivity and quality of crops, with the aim of developing higher quality ingredients and functional foods. In this sense, the objective of this study was to evaluate the ef fects of laser radiation on peanut seeds on agronomic parameters of the crop under field conditions. The experiment was established under field conditions in the town of Nicolás Bravo, belonging to the municipality of Chiapa de Corzo, Chiapas. The seeds were irradiated with a motorized red laser bar of the steelpro® brand, with a wavelength of 636 nm and an intensity of 120 mW. The exposure time of seeds to the red laser was 15 minutes and non-irradiated seeds were used as a control. Each experimental unit consisted of 100 seeds with six replicates. Germination percentage, agronomic characteristics of peanuts and pod yield were evaluated. The results show that laser radiation applied to seeds before sowing has positive ef fects on the agronomic characteristics of pods and seeds such as: the increase in the number of pods and seeds per plant, the dry weight of both components, as well as the yield of pods harvested under field conditions. Therefore, laser radiation applied to seeds is a biotechnological alternative to increase peanut production. It is suggested that further studies be carried out on the harvested seeds to determine if there are changes or improvements in the nutritional quality of the seeds.
Characterization of Encapsulates of Metarhizium anisopliae and its Effect on the Growth of Capsicum chinense Jacq. Plants Inoculated with Fusarium
In Mexico, chili (Capsicum chinense Jacq.) is a crop of economic and nutritional importance whose production is affected by soil phytopathogens, with biological control being a beneficial tool for the ecosystem; in the case of M. anisopliae, its limitation is sensitivity to environmental factors that reduce its effectiveness, so coverage using a polymer matrix is ​​feasible to provide protection, for this reason, the characterization of encapsulated spores of M. anisopliae and its effect on the growth of chili plants inoculated with Fusarium oxysporum was carried out. The encapsulation was done by ionic gelation with sodium alginate and calcium chloride, the water retention and absorption capacity of the encapsulates was analyzed, as well as the viability of the spores and their antagonistic activity in vitro by dual confrontation on F. oxysporum. The capacity of the encapsulation and the spore suspension of M. anisopliae for the control of Fusarium in C. chinense Jacq. plants was also compared. The encapsulate CEM2 (3000 μm ∅, 1 M CaCl2) with 43.4% humidity and 48.3% swelling, showed the highest spore survival of 96% and viability of more than 90% during 75 days of storage at 37 °C. CEM2 demonstrated its antagonistic capacity in vitro by inhibiting the radial growth and sporulation spores of F. oxysporum 62.9 and 60.5% respectively. The application of the encapsulate CEM2 and the suspension spores of M. anisopliae reduced the effect of Fusarium inoculation in chili plants since the values ​​of height, stem diameter and chlorophyll were higher than diseased plants and demonstrated that it promotes growth when applied to healthy plants.
Nutriments Dynamics in the Rhizosphere and its Ef fect on Growth and Distribution of Fe and Mg in Vegetables
The cultivation of family gardens is crucial for producing fresh and high-quality food, with an emphasis on backyard agriculture in Mexico. The vegetable residues generated during the production and consumption of vegetables can be rich in nutrients and of fer opportunities for ef ficient use, such as in animal feed or biofertilizer production. This study evaluates nutrient levels in the rhizosphere of three key crops: broccoli, cabbage, and beet, and analyzes the distribution of Fe and Mg in plant organs. The study was conducted in Suchiapa, Chiapas, Mexico. Soil analysis was performed using a GEMHO-TY model multiparameter soil analyzer (China) before transplanting and again 60 days later to determine the content of nitrogen (N), phosphorus (P), potassium (K), pH, electrical conductivity, and temperature. Raised beds measuring 20 m in length, 0.4 m in width, and 0.25 m in height were established, and a drip irrigation system was installed. At the stage of physiological maturity, soil conditions and the nutrient composition of the species were determined by ICP-OES. Soil analysis revealed significant variations in temperature and electrical conductivity, as well as the identification of critical stages for NPK fertilization. Additionally, in terms of dry matter, a high magnesium content (12.81 mg g-¹) was found in beet leaves, as well as a high iron content (2.2 mg g-¹) in the roots of broccoli and cabbage, highlighting their potential as nutrient sources.
Ef fect of Physical Elicitation on Arachis hypogaea Seeds on the Agronomic Behavior of the Crop
Peanut (Arachis hypogaea) is a crop of great importance in human nutrition and in national and international markets, thanks to its rich nutrient profile and versatile applications in both gastronomy and the cosmetics industry. However, peanut production faces challenges such as drought and phytopathogen control. In this context, this study evaluated the impact of laser irradiation, magnetic fields, and UV-C light on agronomic variables of peanut. An experimental design of completely randomized blocks was used, with four treatments and three replicates each, measuring 41 variables, from germination to morphometric and yield characteristics. The results showed that laser irradiation increased seed biomass, while UV-C light increased the production of pods with three seeds. Surprisingly, the magnetic field resulted in the highest yield in pods, hulls, and seeds, with an 80% increase in production per hectare, especially under drought conditions. These results suggest that physical stimuli could be a valuable alternative to improve peanut yield under unfavorable climatic conditions, of fering new perspectives for both agronomic research and field practice, highlighting the importance of exploring and better understanding the role of these stimuli in enhancing crop performance and food security.
In vitro Propagation of Cof fea arabica var. Borbon Plants Obtained by Chemical Mutagenesis
Cof fea arabica is a species of economic interest in various countries, with Mexico standing out as one of the main exporters. However, there are several pests and diseases, such as cof fee leaf rust, that reduce the production of cof fee fields, af fecting the economy of the producers. Therefore, research on genetic improvement and the propagation of this species has increased in recent years. Among the genetic improvement techniques, mutagenesis stands out. However, mutant plants may exhibit insensitivity to hormonal stimuli. For this reason, the research evaluated the ef fect of dif ferent growth regulators on the morphogenic response of mutant plants obtained through chemical mutagenesis using ethyl methanesulfonate (EMS) during in vitro propagation processes. During the propagation stage, no dif ference was observed in the response of mutagenized and non-mutagenized plants, with the highest shoot production (5.1) occurring with 6 mg L-1 of 6-Benzylaminopurine (BAP). In the in vitro rhizogenesis stage, dif ferences were observed in the morphological response of root formation in mutant plants, with the combination of 3 mg L-1 of naphthaleneacetic acid and 3 mg L-1 of indolebutyric acid resulting in the highest root formation (83%).
Rhizospheric and Endophytic Bacteria with PGPB Potential Isolated from Maize Crop (Zea mays L.) in Chiapas, Mexico
Maize (Zea mays L.) is a crop of significant agricultural and socio-economic importance worldwide. The search for and application of plant growth-promoting bacteria (PGPB) represent a sustainable strategy to enhance agricultural productivity. This study aimed to identify and characterize rhizospheric and endophytic bacterial strains with PGPB potential associated with maize in soils from Chiapas, Mexico, using molecular techniques and in vitro assays. The nitrogen-fixing ability, phosphate solubilization, and siderophore production of each strain were evaluated. Genetic diversity was assessed using ERIC-PCR genomic fingerprinting, and strain identity was confirmed through 16S rRNA gene sequencing. A total of 46 strains were isolated and grouped into 26 genomic patterns. The isolates belonged to the genera Klebsiella, Acinetobacter, and Pseudomonas, followed by Pseudacidovorax, Stenotrophomonas, and Ochrobactrum. The Klebsiella genus exhibited notable capacities for phosphate solubilization, siderophore production, and nitrogen fixation. The specific conditions of the study site played a crucial role in obtaining beneficial microorganisms. These findings highlight the potential of rhizospheric and endophytic bacteria isolated from maize as promising sources for identifying microorganisms with biotechnological applications, contributing to improved crop sustainability and productivity.
Editorial - Tópicos Selectos en Agroecosistemas
El estudio de los agroecosistemas, en su complejidad y diversidad, ha adquirido una relevancia creciente en el contexto de los retos globales, como el cambio climático, la seguridad alimentaria, la conservación de la biodiversidad y la sostenibilidad de los recursos naturales. En este volumen especial se seleccionaron investigaciones innovadoras y avances científicos presentados durante el II Congreso Internacional en Agroecosistemas del Tecnológico Nacional de México (TecNM) a través de las Redes de Investigación "Agricultura Sustentable" y "Genética y Cultura del Maíz", que se celebró con el propósito de fomentar el intercambio de conocimientos y perspectivas sobre la mejora de prácticas agrícolas, la conservación de recursos naturales y el impulso a la resiliencia de los agroecosistemas frente a desafíos ambientales y socioeconómicos.Así también, el evento vinculó al sector académico con los sectores social, productivo y gubernamental, buscando atender necesidades del entorno y contribuir al cumplimiento de la Agenda Estratégica del TecNM para la Autosuficiencia Alimentaria y el Rescate del Campo.
Actinomycetes Promote Growth in Nicotiana tabacum L. Seedlings
Plant growth promoting bacteria (PGPB) are a viable option for sustainable agriculture and an eco-friendly alternative to the excessive use of chemical fertilizers and pesticides. Beneficial microorganisms of this type, such as actinobacteria, have the ability to promote plant growth. The study aims to evaluate the potential of two strains of actinomycetes Streptomyces sp. (EA2 and B8), as promoters of the initial growth of tobacco (Nicotiana tabacum L.) seedlings under controlled conditions. Beneficial characteristics such as indoleacetic acid (IAA) production, biological nitrogen fixation and phosphate solubilization were evaluated in vitro. A completely randomized experimental design was applied with two PGPB treatments: T1 (Streptomyces sp. EA2 + B8); T2 (Trichoderma harzianum), and T3 (Sterile distilled water) control treatment, with three replicates per treatment. The response variables studied in vivo were stem length (TL) and root length (RL), leaf width (W) and length (LH), and fresh and dry biomass of shoot and root parts. The results obtained reveal that strains EA2 and B8 possess BPCV characteristics, such as phosphate solubilization, IAA production and biological nitrogen fixation. T1 strains (EA2 + B8) had a positive ef fect on the evaluated growth indicators, outperforming T2 (T. harzianum) and the control treatment (T3). It is confirmed that the combination of Streptomyces sp strains (EA2 + B8) is an ef fective, safe, and eco-friendly alternative, with the with potential to reduce the application of agrochemicals in tobacco cultivation (N. tabacum L.).
Richness of Arbuscular Mycorrhizal Fungi Associated With Forest Species in the Southeast of the State of Campeche, Mexico
Arbuscular mycorrhizal fungi (AMF) are symbiotic associations of soil and plant roots. They are an alternative for biofertilization, biocontrol and bioremediation agents in production systems. The work consisted of morphologically characterizing the richness and efficiency of HMA in different types of vegetation: medium evergreen forest (SMP), agroforestry system (SAF) and milpa system intercropped with fruit trees (MIAF). In each type of vegetation, the roots of forest species of economic interest for the Programa Sembrando Vida (PSV) were obtained. The root samples were transported to the analysis and biotechnology laboratories of TECNM, Escárcega and Chiná campuses, Campeche, subjected to the sieving and decantation method to isolate spores. Three enriched media were used to evaluate the growth of AMF. Efficiency was validated by root growth and its relationship with mycorrhizal nodulation using different methodologies. Four AMF of the order Glomerales obtained from roots of forest species in SMP were characterized [(Astronium graveolens Jacq. (jobillo), Lonchocarpus castilloi Standl. (machiche), Swietenia macrophylla King (mahogany), Manilkara zapota L. (chicozapote) and Pimienta dioica L. (black pepper)]. The growth and reproduction of AMF in the laboratory was better using the Sabouraud enriched medium, which demonstrated significant results when applied in an 80/20 ratio in SAF and MIAF species. Regarding growth and nodulation efficiency in species such as Cedrela odorata L. (red cedar), Caesalpinia platyloba S. Watt (chakté-viga) and Cordia dodecandra A.D.C. (ciricote), and species in fast-growing crops such as Zea mays L. (corn) and Pachyrhizus erosus L. Urban (jicama), they showed significant differences between treatments, according to the one-factor analysis of variance. In conclusion, HMA are a good option as a biofertilizer in fast-growing and forest species, facilitating the absorption and transport of nutrients and water.
Lettuce Yield (Lactuca sativa L.) Under Different Irrigation Regimes and Nitrogen Dose in the Imperial Valley, California
Lettuce is one of the most widely consumed vegetables globally. China is the leading producer of this crop, followed by the United States, which produces 3.3 million tons per year, with 90% of production concentrated in the south-western region, primarily in the states of California and Arizona. Various studies indicate that nitrogen fertilizer application rates between 363 and 470 kg ha-¹ achieve the highest yields in loose-leaf and ‘iceberg’ lettuce cultivation. However, of this application rate, only 40% of the nitrogen is absorbed by the crop, while the remainder is lost through leaching processes. This issue is compounded by the indiscriminate use of irrigation rates, which vary according to climatic conditions, ranging from 0.45 m ha-¹ in Colombia to 2.0 m ha-¹ in California. These two factors contribute to groundwater contamination and increase production costs. The objective of this study was to evaluate, in terms of yield, two different irrigation rates and three nitrogen fertilization levels using a split-plot design arranged in a randomized complete block with four replicates. The variables analysed included NDVI index, chlorophyll content, stomatal conductance, sap nitrate concentration, yield, and dry biomass weight of lettuce. The results show no statistically significant differences in yield based on the different irrigation rates and nitrogen fertilization levels, suggesting that a change in the current technological package for this crop is feasible, allowing for the application of the treatment with the lowest irrigation rate (0.62 m ha-¹) and lower fertilization (94 kg ha-¹).
Silicon And Its Relationship With Germination And Related Indices In Varieties Of Solanum lycopersicum L. Under Salinity Conditions
Salinity is one of the abiotic stresses that is most af fecting the agricultural sector and tomato cultivation in Mexico and the world. Some alternatives are being considered to counteract the ef fects of salinity, including the use of cation exchangers such as Si (Silicon). The present study aimed to evaluate the response in the germination process to the contribution of three doses of silicon, in dif ferent varieties of Solanum lycopersicum L. subjected to salt stress with NaCl. The study was carried out at the Seed Laboratory of the Department of Agronomy of the Autonomous University of Baja California Sur, Mexico under laboratory conditions. The variables associated with the germination and seedling morphology of three varieties of S. lycopersicum L. were considered, which were evaluated by a completely randomized design in a factorial arrangement with four replications for a total of 27 treatments, resulting from the interaction between varieties. (Cherry, Floradade and Rio Grande), NaCl (0, 25 and 50 mM) and Si (0, 1 and 2 mM). It was obtained that the germination percentage is conditioned by the variety factor and that the fresh biomass and the germination rate (%) are af fected by the 3k interaction (P ≤ 0.001). The Principal Component Analysis showed that NaCl and Si constitute response modulators in fresh and dry biomass accumulation, and root and stem development in S. lycopersicum seedlings under salt stress. It is concluded that there is a dif ferential response in the manifestation of salt stress depending on the phenological state of the plant and variety of S. lycopersicum, verifying the mitigating ef fect of Si in the seedling stage, but not in germination and related variables and indices.
Editorial - Alternativas de Manejo del Suelo o Sustrato en la Producción de Cultivos
La producción agrícola moderna enfrenta múltiples desafíos, entre ellos la optimización del rendimiento y la sostenibilidad de los cultivos. En este sentido, la elección de tecnología de manejo a los cultivos es una prioridad. En el presente número, se ha tratado de conjuntar estudios desarrollados para diferentes condiciones de suelo y ambiente. Se han intentado involucrar la evaluación sobre a) el manejo de la fertilización, b) la evaluación de densidades de población en sinergia con la fertilización mineral, c) el estudio sobre la aplicación de silicio como elemento mineral de potencial benéfico, y d) el uso de acuaponía en un cultivo hidropónico.
Rhizobacteria and Cell Extracts with Antagonistic Potential on Phytophthora palmivora in Theobroma cacao CCN-51
Phytophthora palmivora causal agent of the black ear disease, which causes great economic losses in the crop. The use of rhizobacteria allows reducing the proliferation of pathogens and reducing the use of agrochemicals. The objective of the research is to determine the potential antagonism of rhizobacteria on the resistance structure and propagation of P. palmivora. The research was carried out at the Microbiology and Molecular Biology Laboratory of the State Technical University of Quevedo (UTEQ), Ecuador. P. palmivora strain L8-1 and the rhizobacteria Klebsiella variicola (BO3-4), Enterobacter asburiae (BA4-19 and PM3-14), Pseudomonas putida (BMR2-4 and PB3-6) and Pseudomonas spp. (PM4-13), the trial was divided into three phases: 1) Antagonism of cell extracts on resistance and dissemination structures; 2) Infection levels in pods and 3) Mechanism of protection of cocoa plants. The results indicated that 72 h af ter application, cell extracts of PM3-14 and BA4-19 presented lysis of chlamydospores (80%), and inhibited germination and lysis of zoospores (68%). The application of cell extracts of BA4-19 decreased the advance of infection of P. palmivora (50%) on the cob bark. At 65 days af ter inoculation (dpi), PM3-14 and BMR2-4 rhizobacteria reduced the mortality of CCN-51 seedlings (100%) in the presence of P. palmivora. The application of rhizobacterial strains PM3-14, BA4-19 and BMR2-4 proved to be highly ef fective in controlling P. palmivora, inhibiting its development and providing complete protection to cocoa CCN-51, in addition to promoting its growth.
Characterization of Microorganisms with Biotechnological Potential Isolated from Chemically and Organically Fertilized Agricultural Soils
Agricultural soil degradation is a global issue that negatively impacts productivity. Microorganisms with biotechnological potential play crucial roles in the remediation of contaminated soils and the enhancement of soil fertility. The research was conducted in the Microbiology laboratory of the Universidad Técnica Estatal de Quevedo with the objective of characterizing microorganisms with biotechnological potential isolated from agricultural soils fertilized with chemical and organic fertilizers under controlled conditions. The variables evaluated were pH, colony forming units (CFU) ml-1, and optical density, hypocotyl length, vigor index, germination percentage and germination index. The results indicate that strains isolated from contaminated soil exhibit a higher microbial load, ranging from 7.40×106 to 2.58×108 CFU g-1. Strain Mo-7 showed tolerance to aluminum sulfate and phosphate solubilization activity, and MQ-6 showed high capacity to solubilize urea, phosphate and tolerance to Al2(SO4)3. Turbidity with pendimentalin, MQ-6 reached the highest optical density at 72 hours (2.03). The pH analysis in the presence of Al2(SO4)3, MQ-6 was higher (8.11). In cell concentration with Al2(SO4)3, MQ-6 maintained 8.80E+10 CFU ml-1. In vitro phytotoxicity with pendimentalin and Al2(SO4)3 on Oryza sativa seeds, MQ-6 achieved 100% germination, root length 6.83 cm and vigor index of 82.50. With Al2(SO4)3, MQ-6 achieved 100% germination, hypocotyl length 23.50 cm and high vigor index (303.00). These strains demonstrated their potential to biotransform soil-toxic molecules thereby promoting agricultural sustainability through bioremediation processes.
Potential of Soil Microorganisms: Morphological, Molecular Characterization and Antifungal Activity
Phytopathogens are present in the soil that, when environmental conditions are favorable, infect plants, causing significant economic losses. However, beneficial microorganisms such as Trichoderma spp. and Pseudomonas spp. They are essential for the control of these phytopathogens. Therefore, the objective of this work was the morphological and molecular characterization of beneficial microorganisms and evaluate their antifungal activity. The isolates of Pseudomonas spp. showed dif ferences in colony morphology and enzymatic activities, both being Gram negative and positive for catalase a nd oxidase. Molecular identification identified the isolates as P. aeruginosa and P. fluorescens. The isolates of Trichoderma spp. They presented variability in color, texture and dispersion capacity, being identified as T. harzianum and T. atroviride. The isolates of Fusarium spp. and Phytophthora spp. revealed high phenotypic diversity in colony color, sporulation and mycelial morphology, being identified as F. oxysporum and P. palmivora. Antagonism assays showed that T. harzianum and T. atroviride inhibited the growth of P. palmivora and F. oxysporum by more than 70 and 80%, respectively. These results highlight the importance of identification through morphological and molecular methods, which is essential for the ef fective use of these microorganisms in biocontrol strategies, thus promoting sustainable agricultural practices. Furthermore, isolates of T. harzianum, T. atroviride, P. aeruginosa and P. fluorescens may be an alternative for the control of F. oxysporum and P. palmivora.
Rhizospheric Actinomycetes with Antagonistic Activity to the Black Cocoa Pod (Phytophthora palmivora)
Cocoa black pod disease (Phytophthora palmivora) poses a threat due to the drastic reduction in crop yield and the loss of quality in cocoa beans in Ecuador. An alternative to combat this pathogen could be the use of actinomycetes, which possess characteristics and metabolites that inhibit the growth of plant pathogens. The objective of this study was to identify rhizospheric actinomycetes with antagonistic activity against P. palmivora. Actinomycetes were isolated from soil samples of cacao crops. Five strains were characterized morphologically and biochemically. In vitro (dual culture assays) and in situ (on cacao pods) tests were carried out with the actinomycete strains and their metabolites. Dif ferences were found in the in vitro antagonistic ef fect of the actinomycete strains against P. palmivora. Strain ES3 obtained an inhibition percentage of 74%, followed by strains GC and GC2 with values of 64%. For the in vitro antagonistic ef fect of the actinomycete metabolites on P. palmivora, a dif ference was observed, with GC2 showing the highest inhibition (63%). Likewise, the severity percentage was reduced by up to 55% with strain GC2. The results indicate that actinomycetes have potential as a biocontrol agent for P. palmivora, particularly strain GC2, which showed the best results for in vitro and in situ inhibition of the phytopathogen.
Ef fect of Bacillus sp. and Trichoderma spp. on the Development of Banana Seedlings (Musa spp. AAA) in the Nursery Stage
The production of Musa spp. AAA (banana) generates significant foreign exchange globally. For this reason, its cultivation requires tools that ensure healthy and robust plants from the early stages of development. This research aimed to evaluate the ef fect of Bacillus spp. and Trichoderma spp. on the development of banana seedlings (Musa spp. AAA) in the nursery stage. The study was conducted at Quinta Herrera, located at km 23.2 of the Quevedo – Ventanas road. Species of Trichoderma isolated from the Microbiology Laboratory at the Technical State University of Quevedo and microorganisms from two commercial products were studied. The treatments applied at the soil level were: T1: T. asperellum, T2: T. yunnanense, T3: T. asperellum + T. yunnanense, T4: B. subtilis, T5: T. harzianum, T6: B. subtilis + T. harzianum, and T7: Absolute control. The trials were set up using a completely random design. The results showed that, with the combined application of B. subtilis + T. harzianum, the banana seedlings experienced significantly greater growth compared to the other treatments, with an average of 17.54 cm af ter 6 weeks of evaluation, and a pseudostem thickness of 12.50 mm during this period. Leaf emission was similar across all treatments; however, the development of the leaf area was greater in T6, which reached 1517.52 cm² at 20 weeks of seedling age. Finally, the combined application of the two native Trichoderma strains resulted in greater root development, with longer roots (32.93 cm) and consequently higher fresh and dry root weight, with averages of 367.93 g and 145.84 g, respectively. In conclusion, T6 (B. subtilis + T. harzianum) is recommended for improving the development of banana seedlings in the early or vegetative phenological stage under greenhouse conditions.
Indole-3-acetic acid Acid Producing and Phosphorus and Potassium Solubilizing Bacteria as Growth Promoters in Oryza sativa L.
The rice has economic relevance on a global scale, and the application of agrochemicals has a negative impact on soil fertility and the environment. The objective of the research was to evaluate P and K solubilizing, ındole-3-acetic acid producing and growth promoting bacteria in rice (Oryza sativa L). The work was carried out in the Molecular Microbiology laboratory of the Universidad Técnica Estatal de Quevedo (UTEQ), Campus “La María”. A selection of nine rhizobacteria were isolated and molecularly characterized for IAA quantification and biochemical tests (N and K solubilization). The phytohormone-producing and nutrient solubilizing strains were applied and evaluated on root development in rice for 15 days. From the last experiment, the best strain was chosen for cell multiplication in bioformulations and application together with fertilizers in plants. The application of Enterobacter asburiae BA4-19, Pseudomonas protegens CHA0, Serratia Marcescens PM3-8 and Acinetobacter calcoaceticus BM2-12 had hiould be used to improve crop yield and productivity.gh relative ef ficiency in solubilization of K and P. At 72 h, A. calcoaceticus BMR 2-12 produced higher AIA (17.9 μg mL-1). P. protegens CHA0 increased radicle length (9.50 cm). BIO-IMPULSE + UREA and BIO-IMPULSE + UREA showed greater plant height and root length of (71.7 and 27.0 cm). The application of BIO-IMPULSE with fertilizer showed higher leaf color intensity. It is concluded that rhizobacterial bioformulates It is concluded that rhizobacterial bioformulates could be used to improve crop yield and productivity.
Bacterial Consortia with Growth-Promoting Activity Associated with the Rhizosphere of Echinopsis pachanoi
The rhizosphere is a vital environment where plants, soil, and microorganisms interact, including bacteria that promote plant growth. This study focuses on analyzing bacterial consortia associated with the rhizosphere of Echinopsis pachanoi to enhance the resilience of agricultural crops to various types of stress. Twelve rhizosphere samples of E. pachanoi were meticulously collected and processed in seven areas of the sierra region of Ecuador. At the Biology and Microbiology Laboratory of the Technical State University of Quevedo, growth assays were conducted with rice seeds inoculated with these bacteria, as well as salinity tolerance tests by modifying soil conditions with sodium chloride. The bacterial strains studied showed a decrease in growth under saline stress, with greater inhibition at higher NaCl concentrations, although some strains tolerated concentrations of up to 0.5 M NaCl. All bacterial strains significantly reduced ethylene production in the presence of NaCl, outperforming the controls without bacteria. Specifically, strains BL-15 and CA-01 exhibited a high capacity for 3-indole acetic acid (IAA) production, suggesting a considerable potential for promoting plant growth. These results highlight the potential of bacterial consortia as a sustainable agricultural strategy, of fering ecological alternatives to chemical fertilizers and improving overall agricultural productivity.
Influence of Arbuscular Mycorrhizal Fungi on the Initial Growth of Three Economically Important Forest Species in Ecuador
In recent years, the excessive use of chemical inputs in agriculture has generated negative environmental consequences, such as soil contamination and biodiversity loss, which has increased interest in ecological fertilization as a sustainable alternative. This study evaluates the ef fects of biofertilization with arbuscular mycorrhizal fungi (AMF) on the initial growth of three economically important forest species in Ecuador: white guayacan (Cybistax donnell-smithii Rose), pachaco (Schizolobium parahybum), and laurel (Cordia alliodora). Variables such as mycorrhizal colonization, spore density in the soil, and plant growth in terms of height, diameter, and biomass were evaluated. The results showed that AMF treatments significantly increased mycorrhizal colonization and spore density compared to the control. The liquid inoculum obtained the best results, with 5.84% colonization in pachaco, 3.72% in laurel, and 3.12% in white guayacan. Additionally, spore density was higher in the liquid inoculum treatment, recording 163 spores in pachaco, 128 in white guayacan, and 112 in laurel. Plants treated with AMF also exhibited greater height, diameter, and biomass. Pachaco treated with liquid inoculum reached an average height of 156.6 cm, a diameter of 7.24 mm, and a fresh aerial biomass of 1411 g. However, limitations were identified related to the variability of response among species and the need for controlled conditions to maximize benefits. This study highlights the originality and value of using AMF as biofertilizers, demonstrating their potential to improve sustainability and ef ficiency in forest production. In conclusion, biofertilization with AMF can be an ef fective strategy to promote the growth and adaptation of forest species in nurseries, thus contributing to more sustainable and environmentally beneficial agricultural practices.
Propagation of Ralstonia solanacearum and its Impact on Banana Crops in Ecuador
Global climate change can af fect agricultural production by facilitating the establishment of pests and pathogens. Banana (Musa paradisiaca) is one of the main agricultural products in Ecuador, but it is af fected by the moko disease caused by Ralstonia solanacearum. The objective of this research was to evaluate the potential ef fects of climate change on the ecological niche and potential distribution of this pathogen, and its implications for banana plantations in continental Ecuador. The ecological niche of the bacterium was described from 340 records of its presence globally and modeled with 62 records in Ecuador. Spatial variations in its potential geographic distribution under two climate change scenarios were evaluated and the banana plantations most susceptible to the spread of the pathogen were identified. The ecological niche of the pathogen showed a low centrality in Ecuador compared to the overall niche of the species, indicating that the current climatic conditions in the country are not the most typical for the pathogen, although still within the range it can support. The potential geographic distribution of the current pathogen was 5839 km2, and in future climate scenarios the areas with favorable conditions for its distribution was more than doubled. The plantations most likely to be at risk are in central-northern Ecuador, in Los Ríos, Santo Domingo de los Tsáchilas, Manabí and Esmeraldas provinces. In the future, the extent of the distribution of this pathogen will depend on the establishment and compliance of strict disease management and control protocols.
Editorial Tesoro Subterráneo: Potencial Biotecnológico de los Microorganismos del Suelo
En el corazón de los ecosistemas agrícolas yace un recurso invisible pero esencial para la sostenibilidad de la producción, el microbioma del suelo. Esta comunidad diversa y dinámica de microorganismos representa un verdadero tesoro subterráneo, cuyo potencial biotecnológico ha comenzado a revelarse con fuerza debido a los avances recientes en la ciencia del suelo y la biotecnología agrícola. Durante mucho tiempo, los microorganismos del suelo se consideraron simplemente auxiliares de la fertilidad natural. En la actualidad, sabemos que desempeñan un rol fundamental en procesos múltiples como la movilización de nutrientes, la mejora de la estructura edáfica, la promoción del crecimiento vegetal y la protección contra patógenos. Estos organismos son aliados estratégicos en la transición hacia una agricultura más sostenible, capaz de responder a los desafíos del cambio climático, la degradación de tierras y la demanda creciente de alimentos.
Does Soil Structure Influence Phosphorus Availability in Andosols?
Phosphorus (P) availability in the soil is a limiting nutrient for biomass production in agroecosystems developed in Andosols. Nonetheless, it remains unknown how soil structure af fects the storage and availability of this nutrient. Thus, this research aimed to evaluate the role of soil structure in phosphorus availability using Olsen P as a chemical indicator of availability. Undisturbed and disturbed soil samples were collected following a grid pattern under naturalized and sowed pastures that reflected two dif ferent soil structures (untilled and tilled, respectively). The untilled soil showed higher variability and a higher concentration of Olsen P (5-27 mg kg-1) than the tilled soil (14 mg kg-1). Undisturbed samples collected in cylinders showed that Olsen P continues to increase af ter removing the soil from the cylinder, sieving the sample, and re-extracting Olsen P, resulting in three times the amount of Olsen P found in disturbed samples collected before the experiment. The methodological approach used in this research allowed to highlight the role that soil structure plays in the availability of P over time to improve the ef ficiency of nutrient utilization.
Genes From Microorganisms Used as Biomarkers to Detect Soil Health
Soil health is essential for ecosystem stability, biodiversity, and food security. Soil degradation and contamination adversely af fect soil fertility; therefore, continuous monitoring of physicochemical and biological indicators is required to support sustainable agricultural systems. Biosensors enable the detection of analytes in soil and water, providing rapid alerts and complementing conventional analytical methods. These biosensors, which may include tissues, microbial cultures, enzymes, and antibodies, are widely applied in environmental monitoring, food safety, and medical fields for the detection of a broad range of analytes. In this context, the use of reporter genes endogenously present in organisms is recommended, as they allow the detection of compounds under specific conditions and are extensively used due to their precision and accurate quantification of contaminant concentrations. This review article compiles updated global information with the objective of synthesizing the most relevant factors af fecting soil functionality and limiting its productive potential; additionally, it aims to provide a comprehensive overview of the importance of, and alternatives developed in, various studies for assessing soil health, thereby supporting timely decision-making for its immediate management.
Effects and Prevention of Soil Compaction in Conventional Tillage: Challenges and Solutions
The objective of this research was to analyze the mechanisms of soil compaction under conventional tillage, contributing to the understanding of its characterization, prevention, reduction, and elimination when generated by agricultural machinery traf fic, which negatively af fects seed germination, root development, and consequently, crop yield. A systematic literature review was conducted, analyzing forty-four scientific articles published over the last 20 years and complemented with information from relevant textbooks. The search was performed in databases such as Google Scholar, Scopus, ScienceDirect, SpringerLink, Wiley Online Library, Taylor & Francis Online, Academia.edu, and ResearchGate. The results describe soil compaction, its causal factors and ef fects, and include a quantification of the loads transported by agricultural machinery and the pressures exerted at the tire–soil interface. Various prevention and mitigation strategies are presented, ranging from machinery selection and optimized operation (considering ballasting, tire types, and the incorporation of precision agriculture) to the implementation of appropriate tillage systems. It is concluded that, although compaction is inherent to mechanized agriculture, a comprehensive and proactive approach is essential for its ef fective management, making it crucial to simultaneously optimize machinery–soil contact pressure and improve soil load-bearing capacity and structure to ensure sustainable agricultural production.
Mineralized Biofertilizers in Agroecological Systems: Microbial Interactions and Challenges for Production Scaling
The deterioration of agricultural soils, characterized by the progressive reduction in nutrient availability, organic matter, and the loss of soil structure and populations of beneficial microorganisms, represents a critical challenge that threatens food security due to its adverse ef fects on crop production and the sustainability of agricultural systems. In this context, the implementation of agroecological practices emerges as a key strategy for soil preservation and restoration. Agroecology, as a discipline, integrates ecological principles to design sustainable food systems that operate in harmony with nature, minimizing dependence on chemical inputs that negatively af fect ecosystems. Among agroecological strategies, the use of mineralized biofertilizers stands out as a promising alternative for restoring the soil microbiome, improving plant nutrition, and promoting environmentally friendly agricultural systems. These biofertilizers contain beneficial microorganisms, such as nitrogen-fixing, cellulose-degrading, and siderophore-producing bacteria, that establish symbiotic interactions with plants and the surrounding soil environment. These interactions contribute to key processes such as nutrient mineralization and solubilization, enhancing the uptake and assimilation of essential macro- and micronutrients by crops. The objective of this review is to compile and analyze the agroecological potential of mineralized biofertilizers in plant nutrition and the restoration of degraded soils, with emphasis on their production techniques, the beneficial microorganisms involved, and their reported agronomic benefits in various crops. To this end, a bibliographic search was conducted in scientific databases such as Scopus, Web of Science, PubMed, Google Scholar, SciELO, and Redalyc, covering publications in Spanish and English from the last 15 years, with a focus on experimental studies, systematic reviews, and technical and regulatory literature related to agroecological practices and mineral biofertilization.
Soil Organic Carbon Storage in Cof fee Agroforestry Systems: A review
Agroforestry systems (AFS) are sustainable production alternatives that ef ficiently store more carbon than crop monoculture. However, the simplification of AFS, in terms of canopy structure and species diversity, af fects their carbon sequestration capacity. This work aimed to assess the soil organic carbon (SOC) stocks of cof fee agroforestry systems with distinctive shade gradients at 0-30 and 30-100 cm depths in dif ferent regions of the world. A literature review on SOC storage in cof fee agroforestry systems at the global level was carried out. The cof fee production systems were classified into three groups according to the shade gradient: traditional system (TS) with dense shade, specialized system (SS) with medium shade, and full-sun system (FSS) with no shade trees. TS stored 95 Mg SOC ha-1 at 0-30 cm depth, followed by SS with 83 Mg ha-1, and FSS with 69 Mg ha-1. At 30-100 cm, TS stored 224 Mg ha-1, SS 186 Mg ha-1, and in FSS 126 Mg ha-1. The cof fee AFS in the tropical region has an average of 76 Mg SOC ha-1 at 0-30 cm depth and 170 Mg ha-1 at 30-100 cm. The AFS in the temperate region stored an average of 74 Mg ha-1 at 0-30 cm and 115 Mg ha-1 at 30-100 cm. The global median SOC stock of cof fee AFS was 253 Mg SOC ha-1 to one-meter depth. Our study highlighted that the density of shade trees in cof fee AFS significantly af fects SOC storage, especially in the subsoil. Reinforcing the importance of cof fee AFS for storing SOC and mitigating climate change, this review highlights the need to study SOC at deeper soil profiles to fully understand the variation in soil carbon sequestration capacity of the diverse cof fee agroforestry systems around the world.
Evolution and Trends in Biochar Research: A Bibliometric Analysis
Sustainable technologies such as biochar are required to improve soil health, mitigate greenhouse gas emissions, increase soil organic carbon and productivity. Globally, there is abundant research on biochar, however it is scarce in Mexico, hence, it is necessary to identify international scientific trends for local application. The aim of our study was to analyze the temporal evolution and current trends in scientific research on biochar, especially its development, application and contributions to sustainability at a global level through a bibliometric approach from 2007 to 2022. A Scopus search was conducted on biochar development, application and sustainability, filtering by document type, subject area and stage of publication. A total of 1932 documents were analyzed using bibliometric indicators with bibliometrix and VOSviewer. An exponential increase in biochar research since 2007 was found. China and the United States stand out as the most productive countries. The journals with the highest number of articles were Agronomy and Biomass and Bioenergy. The af filiations with the most publications were Nanjing Agricultural University and Northwest A&F University in China. Recent research trends include topics such as carbon sequestration, methane, nitrous oxide and heavy metals. The keyword network analysis identified three thematic groups: characteristics and benefits of biochar in soil, sequestration of greenhouse gases and aspects of biochar production. Field research is needed to evaluate the positive and possible negative ef fects of biochar in order to determine its applicability in agriculture, taking into account economic, environmental and social aspects.
Mechanisms of Tolerance and Antioxidant Response to Heavy Metals in Trichoderma: A Review
Heavy metals (HM) are toxic to the microbiota of agricultural soils because they af fect the development of bacteria and fungi that promote plant growth and are agents of biological control of pathogenic organisms. In this regard, fungi of the genus Trichoderma have these functions in plants, but like other organisms, HM af fects their growth and biological activity. This article reviews the lithogenic and anthropogenic sources of generation of HM Cu, CrVI, Pb, and Cd, the tolerance mechanisms, and the antioxidant response to oxidative damage in Trichoderma caused by HM. It was identified that in some agricultural soils, the HM content increases mainly due to irrigation with wastewater and the intensive use of agrochemicals, such as pesticides and fertilizers. In Trichoderma, the tolerance mechanisms to Cu, CrVI, Pb, and Cd include biosorption, bioaccumulation, and biotransformation. In contrast, studies of the antioxidant response of Trichoderma to oxidative stress caused by MP are scarce. In the case of Cu and Cr, a relationship between changes in antioxidant enzyme activity and a decrease in the oxidation of cell membrane lipids is reported. This represents an ​​opportunity to understand the toxic ef fect of MP on fungi of the genus Trichoderma, which is part of the biotic soil community.
Bio-inputs: An Alternative to Achieve Sustainable Agriculture
Agriculture involves the cultivation and domestication of plants, but dif ferent agricultural practices worldwide have led to the intensive use of natural resources, synthetic fertilizers and pesticides, as well as the use of heavy machinery and irrigation technologies. This has had negative consequences, mainly through the reduction of biodiversity, the appearance of resistant pests, imbalances in agroecosystems and harmful environmental ef fects. In view of this, research has focused on sustainable agriculture, whose production is economically, socially and environmentally acceptable. To achieve this, the application of bio-inputs formulated with biotechnological techniques from microorganisms, plants, compounds and extracts thereof, capable of improving crop yield and health, has been proposed. Therefore, the objective of this chapter is to show the advances in the production of bio-inputs, their characteristics and application results since they can gradually replace the use of synthetic inputs, reducing the pollutants generated by this sector, in addition to taking advantage of waste from various sectors to incorporate them into the circular economy. It is necessary to continue with research to integrate potential species in the formulation of bioproducts and to deepen in metaomics and bioinformatics with impact and improvement of agricultural activities.
Response of Wheat to Potassium Application at Two Sites With Contrasting Soil Properties in the Mexicali Valley, Mexico
The growth, nutritional status, and yield response of wheat (Triticum aestivum L.) to potassium fertilization were evaluated at two agricultural sites with contrasting soil properties in the Mexicali Valley, Baja California, Mexico. The experiments were conducted during the 2018-2019 fall-winter season using a randomized block design with four K₂O application rates (0, 80, 160, and 320 kg ha-1). The normalized dif ference vegetation index (NDVI), NO₃⁻ and K⁺ concentrations in stem cell extract (SCE), grain yield, grain quality traits (1000-grain weight, protein content, and hectoliter weight), and residual soil chemical properties (pH, salinity, and NO₃⁻ and K⁺ concentrations in saturated paste extract) were measured. At the site with high initial salinity (EC > 5 dS m⁻¹), no significant ef fects were observed for any of the evaluated variables. In contrast, at the lower salinity site (EC = 2.5 dS m⁻¹), statistical dif ferences (p < 0.05) were detected in K⁺ concentration in the SCE at 33 and 65 days af ter seeding. Grain yield and quality were not significantly af fected by potassium fertilization. The initial K⁺ concentrations in soil and SCE indicate suf ficient nutrient availability, which likely limited the agronomic response to potassium fertilization. Based on soil K⁺ values, it is concluded that decisions regarding potassium fertilization should be based on saturated paste extract analysis to avoid unnecessary applications in hyposalic calcaric Vertisols and hypersodic calcaric Cambisols.
Vulnerability of Rainfed Maize (Zea mays L.) to Climate Variability in the Municipalities of Atltzayanca and Huamantla, State of Tlaxcala
Rainfed agriculture faces recurring threats that af fect its productivity year af ter year. Soil moisture and temperature are essential factors for the proper germination, growth, and development of maize. Climatic events such as droughts and frosts, resulting from climate variability, represent the main risks, as they cause direct damage, increase the vulnerability of the agricultural system, and significantly af fect production and, consequently, the economic stability of local producers. The state of Tlaxcala has three rainfed maize-producing regions, with the Oriente Huamantla region being the most important. This region comprises 13 municipalities, among which Atltzayanca and Huamantla stand out due to their higher production levels. Therefore, the objective of this study was to determine the degree of vulnerability of rainfed maize cultivation to extreme climatic events in the municipalities of Atltzayanca and Huamantla. A mixed methodology was employed, integrating quantitative and qualitative approaches. Precipitation and minimum temperature variables for the period 1980–2021 were analyzed together with rainfed maize yield data by calculating means and standard deviations in order to establish correlations and determine the degree of vulnerability. Additionally, 182 questionnaires were administered, and group interviews were conducted in the selected municipalities. The results identified dif ferent degrees of vulnerability, with Huamantla being vulnerable to drought, exhibiting a 20% probability of obtaining low yields under this climatic event, as well as other relevant factors that also af fect crop performance, such as pest incidence and the use of agrochemicals. These findings highlight the need for future research adopting a holistic approach that integrates additional risk factors, including soil conditions, economic context, farmer training, seed type, and the increasing deterritorialization associated with agribusiness.
Crossing Order Ef fect on the Productivity of Three-Way Cross Maize Hybrids
In the High Valleys of Mexico, maize (Zea mays L.) is an economically and culturally important crop. However, average grain yield does not meet the increasing demand; therefore, one strategy to enhance productivity is the use of trilinear hybrids in agrosystems where their yield potential can be fully exploited. For these hybrids, it is advisable to define the most suitable genetic conformation to ensure optimal agronomic performance. This study evaluated the ef fect of dif ferent crossing orders on the productivity of ten trilinear maize hybrids. Field experiments were established in Cuautitlán Izcalli (clay loam soil) and Texcoco (sandy loam soil) under a randomized complete block design with three replications. Key agronomic variables were recorded, including grain yield and its components, male and female flowering, and plant height. The results showed significant dif ferences between environments, attributed to contrasting edaphic and climatic conditions. The average grain yield of the hybrids was 5.50 Mg ha-1. Hybrid H5 (L3 × L4 × L9) showed the highest yield (5.85 Mg ha-1), whereas H1 (L1 × L4 × L9) exhibited the lowest yield (4.70 Mg ha-1). In general, crossing order did not significantly af fect grain yield, except in hybrid H7, in which the combination (L4 × L9) × L7 exceeded its reciprocal by 20.7%. Flowering traits and plant height were consistent across most genotypes, with no relevant floral asynchrony observed. These findings indicate that, for most of the evaluated trilinear hybrids, crossing order was not a determinant factor influencing productivity, which facilitates seed production because seed increase can be conducted using any parental combination. In the specific case of H7, parental order does influence performance; therefore, the optimal combination must be defined during seed multiplication.
The Anthropic Impact on the Development of the Soil the Former Texcoco
Lake Texcoco has been drained and impacted by human activities for over 100 years through the construction of drainage canals and more recently through the construction of an airport project. This caused not only the drying up of the lake, but also the drastic loss of moisture from the lacustrine sediments, so it is unknown if soils are forming. The objectives of the present research are to analyze the morphological characteristics and the chemical and physical properties of the lake sediments/soil of the former Lake Texcoco, to determine the formation of the soil and the natural or anthropogenic factors that have the greatest influence on its development, as well as to know its spatial distribution and the depth at which it is found. The information was generated from a 1:20,000 scale soil study on 18,000 ha of the Lago de Texcoco Federal Zone (CONACYT-COLPOS, 2021). Forty-four soil series were delineated and morphological, physical, and chemical data were collected for each series, which were used to create thematic maps. The salinity of the lake, its artificial (differential) drying, and the introduction of halophytic grasses have favored the formation of soils from lake sediments. They mainly modified the development of prismatic and block structures, the movement of clay and sand particles, and the occurrence of redox conditions. All this indicates a diverse morphology for a relatively small area and the presence of soil formation processes. The edaphic properties show a very heterogeneous spatial and vertical distribution within the soil profile, indicating that the soils of Lake Texcoco are in the early stages of development. However, it is not possible to determine at what depth their formation occurs.
Factors Influencing the Willingness to Pay for Household Composting
The management of household organic waste (HOW) remains a persistent challenge in most developing countries, primarily due to the lack of adequate infrastructure for its recovery. Household composting represents an ef fective strategy for organic waste management, as it enables the production of a value-added product (compost) with agronomic potential and reduces the overall volume of waste. This study aimed to identify the factors influencing willingness to pay (WTP) for the recovery of household organic waste through composting, specifically: (1) WTP for compost derived from HOW, (2) WTP for a service that produces compost from HOW, and (3) willingness to sell HOW by the kilogram generated at the household level. The contingent valuation method was applied to a sample of 382 households in La Paz, Baja California Sur, Mexico. The influencing factors were identified using a binary logistic regression model. The results indicated that occupation, age, household size, and agreement with contributing to environmental protection through the purchase of products manufactured via recycling processes, even when priced higher, were significant explanatory variables.
Application Route and Dose of Silicon in the Production of Cucumber Grown in Tezontle
The accelerated growth of the population increases the demand for vegetables such as cucumber (Cucumis sativus L.). In addition, challenges such as limited arable land and water availability, as well as the negative impacts of climate change, create the need to use substrates as cultivation media and to implement sustainable alternatives to increase yields, such as the use of beneficial elements. The objective of this study was to evaluate two silicon application routes, root and foliar, and three doses (0, 500, 1000, and 1500 mg L-¹) on production, fruit quality, and foliar nutrient content of cucumber grown in tezontle under protected conditions. Treatments were arranged in the field using a randomized complete block design with five replications. Yield increased by 36 and 43.9% with the application of 1500 mg supplied directly to the root and via foliar application, respectively, and by 33% with 1000 mg via foliar application. Fruit firmness increased by 19 and 20% with the application of 1500 mg to the foliage and the root, respectively; whereas this same dose, when applied to the root, increased fruit pH by 4.9%. When 1500 mg was applied to the root, leaf macronutrient content increased by 4.8% for S and 32.9% for N. In contrast, foliar application of 500 mg of silicon increased heavy metal content by 14% for Zn and 61% for Fe; however, these contents decreased with doses of 1000 and 1500 mg, regardless of the application method. Therefore, silicon application increased cucumber yield and fruit quality, modified foliar nutrient content, and the most appropriate dose was 1500 mg supplied either to the root or foliarly.
Production and Mineralization of Sargassum Hydrochar (Sargassum sp.)
Holopelagic sargassum along the coasts of the Mexican Caribbean has affected both natural ecosystems and human activities, with accumulations estimated to reach up to 20 million tons along more than 8850 km of coastline. These large quantities of algal biomass can be converted into recalcitrant carbonaceous material through a hydrothermal process, reducing their volume by up to 60% and facilitating biomass management. Hydrochar derived from sargassum was produced and characterized using different particle diameters (1.0, 0.5, and 0.25 mm) at 180 °C for 2 h. Five grams of hydrochar and natural sargassum were separately incubated at field capacity in 100 g of Vertisol, loam soil, and beach sands from Tulum, Mexico. All substrates were previously sieved and homogenized to a particle diameter of 0.18 mm. Carbon dioxide (CO2) emissions were measured every third day over a one-month incubation period. Absolute and relative mineralization rates in beach sands exhibited the highest CO2 emissions compared with the control and the other soils evaluated. This response was attributed to the presence of aragonite in the sands and exogenous magnesian calcite associated with the sargassum biomass. The particle diameter of 0.5 mm was identified as optimal for sargassum handling, as it resulted in lower CO2 emissions. Sargassum hydrochar should be washed after the hydrothermal process to remove excess labile carbon, thereby reducing CO2 emissions following soil application. Additional studies evaluating different temperature and residence time combinations during hydrochar production are required to further decrease CO2 emissions. It is concluded that sargassum hydrochar offers advantages in terms of volumetric handling and exhibits recalcitrant behavior when applied to beach sands, but not when applied to soils.
Emerging Contaminants from Sewage Sludge Application in Agriculture: Bibliometric Analysis
The production of biosolids in wastewater treatment plants represents an environmental concern, as it increases in parallel with population growth. The literature reports research addressing the application of sludge in agriculture, raising concern about the ef fects of emerging contaminants (EC) that may be present in crops and soils. The aim of this study was to analyze, using bibliometric tools, trends in scientific production related to research on the application of sewage sludge in agriculture during the period from 1992 to 2024. An advanced search was conducted in Web of Science, specifically in the Science Citation Index Expanded and Social Science Citation Index databases, and an analysis of bibliometric indicators was performed in Excel and VOSviewer. A total of 277 registered papers published during the period under study (1992–2024) were obtained. Scientific production followed an exponential growth pattern (R² = 0.9124), indicating an increase in the number of articles published in these years of less than 2% from 1992 to 2011, followed by growth greater than 2%, in contrast to 2021, when the increase exceeded 10%. The author with the highest number of registered publications was Lapen D. R., while the most cited author was Huerta E. The journal with the most published articles was Science of the Total Environment, and the Chinese Academy of Sciences was the institution with the greatest number of registered publications and the highest level of collaboration with institutions in other countries. It is concluded that the growth of literature related to the application of sewage sludge to agricultural fields and its implications concerning EC has been exponential, and that numerous authors are actively publishing in this field of study.
Optimizing Ammonium Concentration in the Irrigation Solution of Pot-Grown Blueberry (Vaccinium corymbosum L.) Plants for Yield and Quality
The aim of this work was to optimize the ammonium concentration in the irrigation solution of pot-grown blueberry plants for fruit yield and quality, under protected conditions. An experiment was developed with blueberry (Vaccinium corymbosum L.) plants var. Biloxi, with six treatments of ammonium concentrations in the irrigation solutions: 0.2 mM, 2.0 mM, 4.0 mM, 8.0 mM, 12.0 mM, and 16.0 mM, which were repeated four times, generating 24 experimental units (EU), with four plants each. At 200, 215, and 231 days af ter treatments application the fruits were harvested to evaluate fruit yield (FY), total fruit yield (TFY), proportional fruit yield for each harvest date (PFY), fruit diameter (FD), and soluble solid content (ºBrix). The results showed that TFY increased with ammonium concentration until 4.0 mM and beyond slightly decreased; the pattern displayed by PFY showed that plants irrigated with solutions with ammonium concentrations higher or lower than 8.0 mM and 4.0 mM, respectively, delayed their fruit ripening. The ef fect of increasing N concentration on FD passed from a slight increase to a null ef fect and to an evident decrease for the first, second, and third harvest dates, respectively. The fruit ºBrix increased with ammonium concentration, but decreased 24.0% and varied only 4.6% for the treatments 2.0 mM and 16.0 mM of ammonium, respectively, from the first to the third harvest date. It was concluded that the optimum ammonium concentration in the irrigation solution of blueberry plants grown in pots under protected conditions was 4.0 mM.
Agro-Ecological Zoning of Stevia Cultivation in the Ríos Subregion, Tabasco, Mexico
Globally, a sector of the food and pharmaceutical industries demands large quantities of stevia (Stevia rebaudiana), and Mexico may have areas with high potential for its cultivation. However, agroecological zoning studies for the establishment of stevia as a new crop are lacking. Therefore, the objective of this study was to characterize the agroecological zones suitable for stevia cultivation in the Los Ríos subregion, in the state of Tabasco. The agroecological zoning (AEZ) methodology of the FAO was used, adapted to the specific conditions of the study area and based on available regional information, considering climate (temperature and precipitation), land suitability by edaphological units and subunits, soil texture, terrain slope, and legal restrictions associated with the presence of protected natural areas. The results indicate the existence of very suitable, suitable, and marginally suitable edaphoclimatic conditions for stevia cultivation. A total of 132 084.93 ha with varying potential for stevia plantations were identified, distributed across the three municipalities of the subregion, including 156 localities. Of this potential area, 48 146.96 ha present favorable climatic and edaphic conditions, while 83 937.97 ha show some degree of restriction, which can be improved through appropriate management. The physical properties of the soil, particularly the composition of edaphological units and texture, constitute a limiting factor for crop establishment, given the predominance of clayey soils in the subregion.
Biological Performance of Eisenia foetida and Quality of Vermicompost Generated from Dif ferent Organic Sources
The degradation of agricultural soils decreases their fertility and nutrient retention capacity, making the application of organic amendments, such as vermicompost, essential for their restoration and functional improvement. The objective of this study was to evaluate the biological performance of the Californian red worm (Eisenia foetida Sav.) and the quality of the vermicompost generated from four organic substrate mixtures: cattle manure + banana rachis (T1), cattle manure + palm rachis (T2), cattle manure + coconut rachis (T3), and cattle manure + market plant waste (T4), with 50:50 ratios (% by volume). The experimental design used was a randomized block with eight replications. The length, population, growth, and reproduction rates of the red worm were evaluated 30 and 45 days af ter the start of the treatments, in addition to the yield and bromatological quality of the vermicompost produced. The best results were obtained af ter 45 days of evaluation. Treatments T1, T4, and T2 showed the highest average worm lengths, with values of 5.58 ± 0.09, 5.53 ± 0.16, and 5.40 ± 0.25 cm, respectively. Treatment T4 recorded the highest population density, with 4319.75 ± 64.71 worms m³, as well as the highest growth rate (0.32 ± 0.01 mg worm⁻¹ day⁻¹) and the highest reproduction index (14.56 ± 0.23%). Treatment T1 had the highest vermicompost yield, with 40.38±0.58 kg m³, an alkaline pH of 8.77 ± 0.15, and a K content of 1.57 ± 0.01%. However, treatment T3 showed the highest organic matter content (50.97 ± 0.21%), total carbon (22.23 ± 0.99%), and a C/N ratio of 22.61 ±0.70. These results demonstrate the potential of vermicomposting as an ef ficient biotechnological strategy for the reproduction of the Californian red worm and the utilization of agro-industrial organic waste, enabling the production of high-quality organic amendments for the recovery and improvement of agricultural soils.
Morphological and Biochemical responses of Cof fee Seedlings (Cof fea arabica L.) to Foliar Application of ZnO and ZnO/Ag Nanoparticles
The application of nanotechnologies in agriculture has gained in importance in recent years, and their impact on plant growth and development has been documented with successes and limitations. In the case of cof fee cultivation, it is a viable alternative compatible with mineral fertilization schemes. The objective of this research was to study the physiological ef fect of zinc oxide nanoparticles (ZnONPs) and silver-impregnated zinc oxide (ZnONPs/AgNPs), synthesized through the sol-gel method on vegetative growth, total chlorophyll concentration, and the synthesis of functional groups in cof fee (Cof fea arabica L.) seedlings. The nanoparticles were characterized by X-ray dif fraction (XRD) and applied to the leaves. Plant height, stem diameter, leaves per plant, and leaf area, concentration of total chlorophylls and functional groups were measured by FT-IR spectroscopy. X-ray dif fraction (XRD) analysis confirmed the crystalline nature of the synthesized nanoparticles, which showed sharp peaks consistent with the hexagonal wurtzite structure, while the ZnONPs/AgNPs showed structures corresponding to the cubic phase of metallic silver. A 58.18% increase in plant height was observed upon application of ZnONPs compared to the control, and 34.78% increase in the number of leaves per plant. The highest chlorophyll concentration was recorded when combining ZnONPs+2.5AgNPs plus fertilizer, with an increase of 81.8% with respect to the control. The combined treatment of ZnONPs/AgNPs with fertilizer significantly increased the accumulation of compounds such as caf feine, sucrose, and carbohydrates. These results demonstrate the potential of nanofertilizers as growth promoters and modulators of functional metabolism in cof fee seedlings, although direct parameters of productivity and bean quality were not evaluated.
Isolation and in vitro Characterization of Actinobacteria from Coastal Soils Against Pathogenic Vibrios for Use as Probiotics in Aquaculture
The use of probiotic bacteria has global importance in aquaculture and aquaponics because they improve growth rates and enhance the organisms resistance to disease, thus increasing production. This study aimed to isolate and characterize actinomycete strains from marine–coastal soils on both coasts of Mexico and to evaluate them in vitro against marine pathogens to determine their probiotic potential and applicability in aquaculture and aquaponics. Fif ty-four actinomycete strains were isolated, and 14 of them exhibited antibacterial activity against the evaluated Vibrio spp. species [V. alginolyticus (CIAD-CAIM 57), V. parahaemolyticus (ATCC-17802), V. harveyi (CIAD-CAIM 1793), and V. vulnificus (CIAD-CAIM 157)]. Based on the results, strain M4 was selected and characterized according to its morphological and biochemical traits. This strain showed enzymatic activity in vitro, confirming its probiotic potential and applicability in aquaculture; it also exhibited increased activity against the pathogenic vibrios tested. These results suggest that strain M4, isolated from coastal marine soil, has probiotic potential and could serve as an alternative to antibiotics to mitigate pathogen attacks in agroaquaculture production systems.
Demand of Macronutrients in Grass Brachiaria humidicola in Response to Time of Year, Fertilization and Cutting Frequency
The species Brachiaria humidicola has high productive potential in the humid Mexican tropics due to its adaptability to flooded and acidic soils of low fertility, supported by its high efficiency in nutrient extraction through its root system and its association with mycorrhizae. The objective of this study was to determine the demand for nitrogen (N), phosphorus (P), and potassium (K) of Brachiaria humidicola Rendle under three climatic periods, different fertilization levels (N, P, and K), and three cutting frequencies. Nine treatments were evaluated in a split-plot design with a factorial arrangement, randomly distributed, each with three replications. The SAS software package was used for the analysis of variance, and mean comparisons were conducted using Tukey’s test. The highest nitrogen and potassium demands were observed after 30 days of regrowth during the rainy season, with 167.0 and 146.6 kg ha-1, respectively, and the lowest at 20 days during the northern season, with 69.1 and 33.5 kg ha-1 for both elements, respectively. Regarding phosphorus, the highest demand occurred in the rainy season after 20 days of regrowth, with 27.6 kg ha-1, and the lowest in the northern season after 20 days of regrowth (8.2 kg ha-1). Although no interaction was detected between climatic periods and fertilization levels, both factors are individually important in plant physiology. Estimating nutrient demand required measuring the internal requirement and total biomass, data that were obtained in this research.
Water Utility in Single-Cross Corn Hybrids withDetasseling and Leaf Removal
In seed production, it is necessary to determine the response of single crosses that serve as parents of three-way hybrids under conditions of limited water availability. The objective of this research was to determine water use ef ficiency and agronomic variables of three single-cross maize hybrids (IA442 F × IA446, IA424 F × IA249, IA442 F × IA213), parents of three-way hybrids, under tassel and leaf elimination treatments. The experiments were conducted in two locations in the Valley of Mexico, Cuautitlán and Texcoco, State of Mexico. The three hybrids were evaluated under the following treatments: without detasseling (control), detasseling (D), and detasseling with removal of one to five leaves (D+1, D+2, D+3, D+4, D+5). A factorial experiment was established using a randomized complete block design with three replications. Total water use ef ficiency and grain yield showed significant dif ferences between environments (p < 0.05): 2.2 kg m–³ and 9.98 Mg ha–¹ in Cuautitlán, and 0.9 kg m–³ and 6.39 Mg ha–¹ in Texcoco. Significant dif ferences were also observed among crosses, with values of 1.5 kg m–³ and 7.8 Mg ha–¹ for IA442 F × IA446; 1.3 kg m–³ and 6.87 Mg ha–¹ for IA424 F × IA249; and 1.9 kg m–³ and 9.99 Mg ha–¹ for IA442 F × IA213. The detasseling and leaf-removal treatments produced a significant ef fect only on ear length; however, tassel removal alone resulted in higher water use ef ficiency and grain yield (1.7 kg m–³ and 9.05 Mg ha–¹). The IA442 F × IA213 genotype showed the highest water use ef ficiency, reaching 2.7 kg m–³ under limited water conditions (Cuautitlán). No ef fect of detasseling or leaf removal on total water use ef ficiency was observed.
Fermented Mucilage from Theobroma cacao L. Pods for Weed Control Through Allelopathy
Weeds play an important role in ecological systems due to their rapid growth, high adaptability, and invasive nature. In agricultural systems, their management constitutes a fundamental practice within the set of cultural operations, along with pruning, shade regulation, and pest control, as it directly af fects the yield of Theobroma cacao L. (cacao) crops. The objective of this study was to determine the ef ficacy, severity, and phytotoxicity of fermented mucilage from cacao fruits, considering its allelopathic potential as a herbicidal agent for weed control in cacao plantations. Six treatments were applied: T1 (1 day), T2 (30 days), T3 (60 days), T4 (90 days), T5 (5 years), and a control (water), using a randomized complete block design with four replications. The bromatological properties of each treatment were previously characterized. Weed control indicators such as ef ficacy, severity, and phytotoxicity were evaluated five and ten days af ter application. The treatment with fermented mucilage for five years (T5), with an acetic acid content of 6.37%, showed the greatest ef fectiveness in weed control. This treatment had a dif ferentiated impact on grasses and dicotyledons, being more ef fective against the latter. High phytotoxicity was observed in species such as Portulaca oleracea (purslane), which exhibited total desiccation of the foliage, and Rottboellia exaltata L. (cocoa vine), which showed complete wilting of the plant. These results suggest that the use of cacao mucilage with prolonged fermentation periods may represent a sustainable and selective alternative for weed management, particularly against broadleaf species, in cacao production systems.
Impact of Biochar and Microorganisms on Cof fee Seedlings Resilience to Water Stress and Diseases
The impact of global warming on cof fee crops has made it necessary to seek strategies that promote resilient plantations capable of withstanding increasingly frequent and intense drought periods. This study evaluated the incorporation of biochar and microorganisms in cof fee seedlings to assess the resistance of plants to diseases and water stress. The trial was conducted in randomly subdivided plots with normal and interrupted irrigation, dif ferent combinations of biochar and microorganisms, and four cof fee varieties. The response variables included plant height, fresh weight, leaf area, nutrient content, disease incidence and severity, and soil physicochemical properties. By incorporating biochar with microorganisms, plants under water stress did not increase their root development compared with the other treatments; however, dif ferences of 6 to 8 cm in height were observed, with up to three times more biomass among varieties and greater nutritional balance at the leaf level. Although the incidence of diseases did not decrease, their severity was reduced. The Obatá variety, with the combination of biochar and microorganisms, showed better growth performance under water stress conditions compared with the control, as well as lower disease severity. In addition, the application of biochar and microorganisms to the soil reduced acidity, increased cation exchange capacity, electrical conductivity, and the carbon/nitrogen ratio, improved phosphorus levels, and decreased iron content. Therefore, the application of biochar and microorganisms may be considered a potential strategy for managing cof fee seedlings to enhance their growth and resistance to water stress.
Molecular Characterization of Bacterial Isolates of the Biol Elaborated with Native Mountain Microorganisms and its Ef fect under Deficit Irrigation Conditions on Bell Pepper (Capsicum annuum L.)
The search for sustainable agronomic strategies is essential to address water scarcity and mitigate the negative impacts associated with conventional agricultural practices. In this context, this study aimed to molecularly characterize bacterial isolates from a biol prepared with native mountain microorganisms and to evaluate their interaction with deficit irrigation in bell pepper (Capsicum annuum L.) cultivation. Six treatments were implemented: T1, 100% of crop evapotranspiration (ETc) without biol; T2, 75% of ETc without biol; T3, 50% of ETc without biol; T4, 100% of ETc with biol; T5, 75% of ETc with biol; and T6, 50% of ETc with biol. For molecular characterization, PCR products were analyzed using the BLAST tool in the GenBank® database. The results of 16S rRNA gene sequencing revealed the presence of bacteria such as Enterobacter asburiae, Enterobacter hormaechei, and Serratia marcescens, and also indicated the formation of two distinct subgroups. Regarding agronomic variables, the use of biol at 100% ETc (T4) was superior in terms of plant height, commercial fruit weight, and yield, whereas 50% ETc without biol (T3) showed the lowest values in all evaluated variables. Conversely, treatment T6 stood out for its water use ef ficiency, achieving a yield of 30.73 kg m–³. The use of biol improves the agronomic performance of bell pepper cultivation and allows a reduction of up to 50% in water consumption without significantly af fecting yield.
Application of a mixture Design to Evaluate High Concentrations of Ni2+, Fe2+, Zn2+ and Mn2+ in Nutrient Solutions on the Mineral Composition and the Tomato Yield
The intensive production of fruit vegetables uses high amounts of fertilizers and pesticides, which contain in their chemical composition elements such as nickel (Ni), iron (Fe), zinc (Zn), and manganese (Mn). These elements are absorbed by plants and accumulate in the fruits, increasing the health risk to consumers. The objective of this study was to apply a mixture design to evaluate nutrient solutions with high concentrations of Ni²+, Mn²+, Fe²+, and Zn²+ on the mineral composition and yield of tomato (Solanum lycopersicum cv. SV8579TE). The hydroponic system was closed and used peat (Sphagnum parda) as the substrate. The experimental design employed was a centroid simplex [4,3] with 15 nutrient solutions and six replicates per treatment, for a total of 90 experimental units. The nutrient solutions were generated using the mixture design methodology with the Design Expert sof tware (version 11). The 15 mixtures of Ni²+, Mn²+, Fe²+, and Zn²+ caused growth arrest of the apical meristem of the main stem and morphological alterations in the plants. The concentrations of Ni, Fe, Zn, and Mn in the fruits were significantly (p ≤ 0.05) af fected by the mixtures. The highest values of Ni, Zn, and Mn were obtained in the pure mixtures, where the element of interest was at the highest concentration (12 mg L-1). The regression models describing these results on the response surface were multiple linear, where increases in the proportions of Ni²+, Mn²+, and Zn²+ in the mixtures increased the concentrations of these elements in the fruits. The average concentrations of Ni, Fe, Zn, and Mn in the fruits did not exceed the limits established by international organizations. Therefore, the consumption of these tomatoes does not represent a risk to human health. The average production (59.3 Mg ha-1) was 37.8% lower than the average yield (95.3 Mg ha-1) obtained in Sinaloa.
Impact of Organic and Mineral Fertilization on the Reductase Activity of Three Pinto Bean Varieties
Enzymes are molecules that catalyze chemical reactions; in plants, they participate in various processes related to development and defense against biotic and abiotic stress. In green chemistry, microorganisms, seeds, and plants have been studied as biocatalysts to obtain environmentally friendly products. The ef fect of organic and mineral fertilization on the seed reductase activity of three pinto bean varieties, San Rafael (SR), Libertad (Lib), and Vaquita (Vaq), was evaluated. The evaluation was carried out over three crop cycles under greenhouse conditions. Three doses of organic fertilizer (a commercial sargassum extract), three doses of mineral fertilizer, and combinations of both were considered, along with an unfertilized control. Reductase activity was measured using HPLC by quantifying the production of hydroxymethylbenzene through the reduction of benzaldehyde, with the seeds serving as the reductase source. Biocatalytic activity followed the order SR > Lib > Vaq. Enzymatic activity increased with higher doses of organic fertilization, whereas mineral fertilization had no significant ef fect. In the second crop cycle, biotic stress caused by a red spider mite infestation resulted in increased biocatalytic activity in all three varieties. Seeds obtained from crops fertilized with sargassum extract are a good source of reductases.
Settleable Matter from the Parcona Pond as a Soil Amendment for Semi-Arid Soils of Ica-Peru
Wastewater treatment in oxidation ponds primarily focuses on water purification, often overlooking the potential reuse of the accumulated sediments. The objective of this study was to describe the settleable matter from the oxidation pond in Parcona and assess its potential value for semiarid soils in Ica, Peru. A descriptive study design was applied in the oxidation pond, where five sampling lines (SL-1, SL-2, SL-3, SL-4, and SL-5) were established to ensure representative spatial sampling. In each sampling line, three sediment samples were collected and subsequently homogenized to form a composite sample, which was analyzed in duplicate to determine pH, organic matter content, texture, nitrogen, and phosphorus levels. The main results indicated neutral pH values ranging from 6.6 to 7.3. Organic matter content varied from moderate to very high (2.21%-13.87%). Textural analysis showed high clay content in SL-1 (11.3 g cm-³) and SL-2 (12.3 g cm-³), while SL-3 (73.8 g cm-³) and SL-4 (65.8 g cm‑³) were predominantly silt. Nitrogen levels were elevated in SL-2 (1092 mg kg-1) and SL-3 (1321 mg kg-1), and phosphorus was consistently high across all sampling lines. The physicochemical variability of the sediment load reflects complex sedimentation processes that had not been previously characterized. The primary value of this finding lies in the potential use of this biosolid as an agricultural fertilizer; however, variability in pH, organic matter, and texture necessitates careful management to avoid adverse effects on agricultural soils. Overall, the sedimentable material from the oxidation pond exhibited exploitable nutrient properties, reinforcing its value as a fertilizer for semiarid soils within the framework of a circular economy.
Model of Water Flow Infiltration Force in a Soil Mass
The flow of water in the soil generates processes that can be passive and active and manifest themselves in dif ferent ways. The objective was to propose a mathematical model to estimate the infiltration force of water in the soil in three components. It was based on formulations of Hydrology, Newton’s Law, and hydrogeology, and the water flow-soil mass system was identified through vertical, lateral, and superficial infiltration. To apply the formulations, reported data and experimental review of a multifunctional infiltrometer were used, and dry, saturated, and supersaturated soil masses were chosen. It has been obtained that the proposed model relates the variation of the infiltration force in direction, magnitude, and distribution, even for the same type of soil, the displacement is at dif ferent instantaneous speeds, due to the moisture content, porosity, hydraulic conductivity, and depth of the soil profile. The limitation is that no more multifunctional infiltrometers have been developed to apply the proposed model, but the results obtained can be associated with: i) if the vertical infiltration force predominates, there is greater ef fective infiltration as the first impulse of recharge, ii) if the lateral force predominates, the presence of soil instabilities, such as landslides, is possible, and iii) if the surface force predominates, the result is runof f or flooding on the soil.
Effect of Hydraulic Retention Time on Municipal Wastewater Treatment and Energy Recovery at a Semi-Pilot Scale Using a Modular Bioelectrochemical System
Bioelectrochemical systems (BES) remove high concentrations of organic and inorganic contaminants and generate energy. It has been proven that they are more ef ficient when working with small-volume modules (such as stacks or cascades) than with a large reactor volume. In this work, the ef fect of hydraulic retention time (HRT) on the removal of chemical oxygen demand (COD), biochemical oxygen demand (BOD5), total solids (TS), total suspended solids (TSS), total coliforms (TC), fecal coliforms (FC), helminth eggs (HE), and power generation of a modular bioelectrochemical system consisting of ten dual-compartment microbial fuel cells (MFC) of 2000 mL each during the treatment of municipal wastewater (MWW) was assessed. The increase in HRT had a positive impact. In a 5-h HRT, the removal ef ficiency percentages of COD, BOD5, TS, TSS, TC, FC, and HE were 66.46, 34.18, 36.76, 53.84, 99.99, 99.99, and 91.88%, respectively. Likewise, at this same HRT (5 h), the highest maximum power density of 5.709 mW m-3 and the coulombic ef ficiency of 0.0056% were obtained. Results showed that the modular BES increases energy generation and contaminant removal, especially pathogens (TC, FC, and HE).
Influence of Biofertilizers on the Development and Mineral Composition of Broccoli (Brassica oleracea var. italica)
This study aimed to evaluate the impact of dif ferent biofertilizers on broccoli cultivation during the autumn-winter 2022-2023 cycle in Saltillo, Coahuila, Mexico. Three combinations of Bacillus spp. and vermicompost leachate were tested using a randomized complete block design with four replicates, each consisting of five plants. The variables evaluated included fresh and dry biomass, stem diameter, inflorescence moisture, and the mineral content of macro- and micronutrients in the roots, inflorescence, and foliage, as well as glucosinolate concentration and chlorophyll estimation. The application of biofertilizers significantly influenced inflorescence moisture and promoted nutrient accumulation, with notable dif ferences in nitrogen, phosphorus, calcium, and potassium. Moreover, the treatment with vermicompost leachate increased chlorophyll content, and high levels of glucosinolates were observed, although with considerable variability. These findings highlight the potential of biofertilizers as a viable alternative to improve the nutritional and functional quality of broccoli, particularly regarding nutrient accumulation and bioactive compound content, positioning them as a promising option to conventional fertilizers in sustainable agricultural systems.
Study of a Synthetic Surfactant in Sea Water Bioremediation and its Toxicity With Bioassays on Lettuce Seeds and Artemia salina
Oil pollution and its derivatives represent a serious environmental problem that requires ef fective remediation strategies such as bioremediation, a technology that has been widely studied and applied. This process employs microorganisms to degrade, transform, or reduce pollutants and their environmental impact. However, it faces challenges such as the low bioavailability of contaminant compounds. In this study, the bioremediation of synthetic seawater contaminated with total petroleum hydrocarbons (TPH) was evaluated using the bacteria Wautersia eutropha and Pseudomonas aeruginosa in combination with the synthetic anionic surfactant 5-(3,4,5-trishexyloxy)benzyloxy disodium isophthalate (AS-5) at a concentration of 200 mg L-¹. The results showed TPH degradation rates of 85.3% with P. aeruginosa, 78.5% with W. eutropha, and 85.9% with both strains combined. In the AS-5 bioassays, the median lethal concentration (LC50) was 586.33 mg L-¹ for Artemia salina and 1100 mg L-¹ for Lactuca sativa L. Furthermore, the integral phytotoxicity index (IPI) was determined in lettuce seeds at concentrations of 50, 100, and 200 mg L–1 of AS-5, yielding values of 11.6, 29.0, and 38.1%, respectively. The most af fected parameter was hypocotyl elongation.
Biological Properties of Soils in the Province of Chaco-Argentina with Dif ferent Agricultural Practices
Soil quality is defined by its capacity to function within ecosystem boundaries, support productivity, maintain biodiversity, and preserve water and air quality. The diversification of productive activities, both agricultural and livestock-based, contributes to improving soil use. In this context, it is essential to identify indicators sensitive to land-use changes, with biological parameters being particularly suitable for estimating soil quality. The objective of this study was to evaluate the biological properties of soil under various agro-livestock management practices compared to its initial condition in wooded areas: forest soil (considered pristine) (Mon), agricultural soil (ChAg), and soil with a livestock management history of over 40 years (ChMix). Biological indicators included microbial biomass carbon (MBC), soil respiration (RES), easily extractable glomalin (EEG), potentially mineralizable anaerobic nitrogen (PMN), total organic carbon (TOC), particulate organic carbon (POC), total nitrogen (TN), and particulate organic nitrogen (PON). The results highlight the importance of biological variables as sensitive indicators and quantitative diagnostic tools for decision-making tailored to the conditions of each agroecosystem. The ChMix system displayed intermediate values in most variables, representing a productive alternative with a lower impact on soil quality. The attributes EEG and PMN stood out as good quality indicators, showing significant dif ferences and evidencing changes between pristine and agricultural-livestock conditions. When analyzing the various organic soil fractions, the greatest dif ferences were observed in POC and PON, demonstrating their sensitivity in distinguishing between natural systems and dif ferent agricultural management practices.
Post-Fire Changes in Soil Chemistry of the Savannas of the Paraguayan Humid Chaco
Contradictory results regarding the ef fects of fire on the chemical properties of soil are found in the existing literature. This study evaluated the ef fects of burning on the pH, organic matter (OM), phosphorous (P), calcium (Ca), magnesium (Mg) and potassium (K) in the soil of savannas in the Benjamín Aceval district of the Paraguayan Humic Chaco, over the medium term (two years af ter the wildfire event). The selection of sampling sites was based on the Fire Severity Index (dNBR). The treatment factors were the type of land cover (savanna and flooded savanna), burn condition (burned and unburned), and sample depth (0-3 and 3-6 cm). Regarding pH, no significance was found with any factor or their interactions. For OM, a significant interaction was found between burn condition and sampling depth. For P, the interaction between the type of cover and depth was significant. Concerning C, M, and K, a significant ef fect was observed based on sampling depth. Overall, the results indicate that two years af ter the fire, the ef fects of burning on the chemical properties of the soil were limited and dependent on the evaluated variable.
Productive and Economic Comparison Between Aquaponics and Hydroponics in Different Seasons
The productive and economic performance of experimental aquaponic and hydroponic (NFT Technique) systems for the production of tilapia (Oreochromis niloticus), lettuce (Lactuca sativa) and cucumber (Cucumis sativus) are evaluated. Two plant production cycles and a single fish production cycle were analyzed. The systems were compared regarding production and economic benefits. Production of 21.33 kg m-3 of fish, 9.75 pieces of lettuce m-2, and 0.0083 kg m-2 of cucumber was obtained in the aquaponic system. In the hydroponic system, a production of 10.49 pieces of lettuce m-2 and 0.94 kg m-2 of cucumber fruit was obtained. The benefit-cost ratios were 1.50 in the aquaponic system and 2.18 in the hydroponic system, while the aquaponic system was superior regarding net profit (US$ 36 693.32 ha-1) than the hydroponic system (US$ 24 313.42 ha-1). It is concluded that the hydroponic system had higher plant production; however, aquaponics is more profitable due to the production of fish and vegetables.
Influence of Sargassum Extract and Mineral Fertilizer on the Yield of Pinto Bean (Phaseolus vulgaris L.) cv. San Rafael
Bean seeds are of significant global importance due to their high nutritional value. Mineral fertilizers are commonly used to enhance crop productivity; however, their excessive application can be detrimental to the environment. An alternative is the use of sargassum extracts, which both reduce the demand for mineral fertilizers and help mitigate the environmental and economic problems caused by massive sargassum accumulations on coastal areas. This study evaluated the ef ficacy of combining organic fertilization based on sargassum extract (S) with mineral fertilizer (M) at dif ferent doses in pinto bean cultivation. The experiment was conducted over two cropping cycles using three concentration levels of Sargassum (S1, S2, S3), three of mineral fertilizer (M1, M2, M3), their combinations (S/M), and an unfertilized control (C-), in a randomized experimental design. Application of either M or S fertilizers increased yield compared with the control. The S2/M2 and S3/M2 combinations increased seed weight by 5% and 10%, respectively, relative to M3 alone, while S1/M2 and S2/M1 produced seed weights comparable to M3. In contrast, S3/M1 resulted in a 7% reduction in seed weight compared with M3. Neither the DPPH radical scavenging activity nor the anthocyanin content of the seeds was af fected by fertilizer treatments. These findings indicate that the combined use of sargassum extract and mineral fertilizer is a promising strategy to reduce mineral fertilizer inputs without compromising yield, while also valorizing sargassum—a low-cost material that poses environmental challenges but contains beneficial compounds for plants.
Spatiotemporal Dynamics of Land Use and Cover Changes in the Hueyateno Micro-Watershed
The Hueyateno micro-watershed is located in the upper part of the Sierra Norte de Puebla and covers 8347 ha. Between 1993 and 2023, it experienced significant land use and cover transformations, reflecting the ef fects of urban and agricultural expansion to the detriment of natural ecosystems. These changes caused forest cover loss, af fecting water regulation and soil stability, which represents a challenge for environmental sustainability. The aim of this study was to analyze spatial and temporal changes to identify transformation patterns and their implications. Landsat satellite images from 1993, 2014, and 2023 were used, processed through supervised classification in geographic information system sof tware, calculating change rates and transition matrices. Results show a forest loss of 2590.80 ha between 1993 and 2023, mainly converted into agricultural areas (1914.43 ha) and urban zones (656.10 ha). Urban growth was initially concentrated in the northern area, progressively extending to the central and southern zones, favored by flatter topographic conditions. Change rates revealed sustained urban expansion, while agricultural land experienced intense growth over 30 years. Territorial planning limitations contributed to landscape fragmentation and the loss of ecosystem services. Therefore, the findings highlight the need for comprehensive land management policies that balance socioeconomic development with environmental conservation. Moreover, integrating spatial and temporal analysis of land use change provides relevant information for designing sustainable strategies in similar micro-watersheds, underlining the importance of this study for informed decision-making.
Spatial Distribution of Heavy Metals from Anthropogenic Origin, in the Sub Basin of the Alto Balsas, Puebla, and Tlaxcala
In the metropolitan area of Puebla and Tlaxcala, waste discharge into the Alto Balsas sub basin constitutes an environmental issue that has increased throughout recent years due to the expansion of urban settlements, causing health issues derived from consumption and irrigation water use. The objective was to evaluate heavy metal contamination in soils and surface water used for agricultural production and to conduct a spatial analysis of heavy metals locating the potential sources of contamination. The study was carried out in three representative areas of the sub-basin, collecting water and soil samples. The geoaccumulation index (Igeo) and enrichment factor (EF) were obtained, and the spatial distribution analysis for heavy metals was made by interpolation using the IDW method. The results showed median concentrations of Cd, Co, Cr, and Ni above the U.S. EPA recommendations for irrigation water-use. Cr values exceed the maximum levels for agricultural soil-use. The Igeo showed strong to moderate contamination in concentrations of Cd, Co, and Zn elements, while Cr, Cu, and Ni resulted in moderate contamination. The EF showed significant enrichment for elements such as Cd, Co, Cr, Cu, and Zn, proving that the contamination is related to anthropogenic sources. From the spatial distribution, it is possible to identify the contamination sources of heavy metals, associating the causes with the increasing urban areas and the industrial growth in the Alto Balsas region, which, due to the lack of regulation for waste discharges contributes to the accumulation of heavy metals, generating pollution in agricultural soils.
Comparative Assessment of the Total Water Stress Index (TWSI) and Water Requirement Ef ficiency (WREI) in Agricultural Crops Using Water Footprints
Multiple indexes are used to assess water scarcity in irrigated agriculture, such as the Crop Water Stress Index (CWSI), the Agricultural Water Stress Index (AWSI), the three-dimensional indices (WSIGreen, WSIBlue, WSIGrey), and the Water Use Ef ficiency Index (WUEI). However, these indices do not account for the cumulative water stress throughout the agricultural cycle, nor do they integrate real water footprints under scarcity conditions. This study aimed to evaluate the Total Water Stress Index (TWSI) and the Water Requirement Ef ficiency Index (WREI) in agricultural crops of an irrigation module, using meteorological and physiological information for the Baseline (LB) and hydrometric, agricultural, and water footprint data for the Real Condition (CR). The research was empirical-associative in nature, with a non-experimental design, and analyzed agricultural and hydrometric statistics as well as water footprints (green, blue, and total) under both LB and CR scenarios. Furthermore, meteorological data simulated by the WXGEN climate generator were processed in the CROPWAT sof tware to calculate crop irrigation requirements in both scenarios. The results include four mathematical expressions for calculating the TWSI and the WREI. Under LB, the module’s total water footprint was 12 504.57 m³ Mg–¹, while under CR it was 8 075.78 m³ Mg–¹. The average TWSI was 45.43%, and the average WREI was 54.57%. The main limitations were the lack of in situ measured meteorological and physiological data. Nevertheless, the TWSI and WREI indices proved to be ef fective tools for quantifying total water stress and irrigation requirement ef ficacy, since the TWSI and WREI, calculated using the potential water footprints of the Baseline (LB) and the real water footprints of the Real Condition (CR), provided a robust methodological framework for sustainable water management in irrigated agriculture under conditions of water scarcity and climatic variability.
Nutrient Input from Litterfall in Forest Ecosystems
In forest ecosystems, litterfall plays a fundamental role in nutrient transfer within the plant-soil system. The objective of this study was to evaluate litterfall deposition, nutrient input and ef ficient use of the macronutrients in three forest ecosystems (Pine, Oak and Pine-Oak) in Galeana, Nuevo León, located in northeastern México, under the hypothesis that each plan community exhibits distinct patterns due to its structure and diversity. Ten litterfall traps of 1 m2 were randomly placed in a 2500 m2 plot (50 m × 50 m) in each forest ecosystem. The collections of deposited material were conducted biweekly to obtain a monthly representation of litterfall over a 16-month period. Litterfall was highest in the Pine ecosystem (579.74 g m-2 year-1), followed by Pino-Oak (486.40 g m-2 year-1) and Oak (362.49 g m-2 year-1) ecosystems. The order nutrient deposition was Ca > K > Mg > P, with the highest nutrient concentration found in the Pine-Oak ecosystem and the lowest in the Pine ecosystem. Regarding nutrient ef ficient use, Mg and P were identified as limiting elements in all three ecosystems, while Ca and K showed the highest concentrations in the litterfall. The results of the highest nutrition deposition were not related to the amount of leaf litterfall, evidencing spatial and temporal variation in leaf litter production and nutrient deposition. Therefore, the litterfall, nutrient production and their use ef ficiency depend on the plan diversity and chemical composition of litterfall in each ecosystem, as well as in climate and species phenology.
Evaluation of Pecan Nutshell (Carya illinoensis [Wangenh.] K. Koch) in the Production of Jalapeño Pepper (Capsicum annuum L.) Seedlings
Due to its high salt content and phytotoxic substances, pecan nutshells (Carya illinoensis [Wangenh.] K. Koch) pose an environmental problem when discarded in large quantities. This study aimed to evaluate the use of pecan nutshells in the production of semicomposts for growing jalapeño pepper (Capsicum annuum L.) seedlings. The research consisted of three experiments: in the first, the shells from three shelling facilities were characterized based on pH, electrical conductivity, and germination index. In the second experiment, pecan shells were mixed with horse manure to produce semicompost, which was then used as a substrate for jalapeño seedlings in the third experiment. Statistical differences were observed in the salt concentrations and phytotoxic compound content among the shells studied, which were reflected in the germination index. The results showed that the semicomposts produced did not exhibit differences in the evaluated variables, indicating that the semicomposting process effectively neutralized the variations initially observed in the shells from different processing facilities. It was found that using pecan nutshell semicompost, either alone or mixed with peat, produced seedlings that were statistically comparable to the control treatment (peat) in quality parameters such as slenderness and Dickson’s quality index, in three out of the six treatments studied.
Culture of Agricultural Soil Quality Monitoring in the North Center of the State of Sinaloa. Sustainable Perspective and Importance from Local Laboratories
The opinions of soil laboratory technicians in the north-central region of the state of Sinaloa were analyzed in an attempt to understand the culture and importance of agricultural practice in this highly agricultural region. The starting point is that this group of specialists believe that the monitoring of soils used for agricultural purposes has not been an issue addressed by producers, impacting the sector’s sustainable outcomes. Using a quantitative cross-sectional descriptive methodology and a 20-item Likert-type survey as a collection technique, topics such as traditional agricultural practices, obstacles to agricultural production, soil quality monitoring, and sustainable agriculture were addressed. The surveys were conducted with a representative population of 71.43% of the sample, in five agricultural soil laboratories, out of a total of seven, located in three municipalities in the proposed area: Guasave, Juan Jose Rios, and Ahome. Our results show evidence that the monitoring of soil quality is a topic understudied by researchers and scarcely applied by farmers. Furthermore, current actions are insuf ficient to achieve significant changes, and specialized technical assistance is lacking. While some young producers engage in this practice, conventional approaches prevail, hindering the sector’s sustainable development. Changes in sector governance are needed to promote awareness and action: training, technical assistance, and agronomic advice; promoting the design and implementation of public policies and programs that facilitate sustainable, resilient, and corrective agronomic practices that aid long-term soil regeneration; and seek to establish agreements and networks between sector governance and private initiatives (laboratories and universities) that support agricultural producers in this important monitoring activity. One limitation to this research was the reluctance of laboratory technicians or laboratory managers to respond to surveys.
Physical-Chemical Characterization of Soil in Two Mezcal Production Areas, in the District of Miahuatlán, Oaxaca
For the establishment of any crop, it is essential to know the properties of the soil since a lack of knowledge of the quality of the soil and its deficiencies in organic reserves and mineral nutrients becomes a limiting factor to obtain the desired yield and quality in the crop. In the present work, the physical-chemical characterization of the soil with maguey production in the municipalities of Sitio Xitlapehua and San Luis Amatlán, Miahuatlán de Porfirio Díaz, Oaxaca, was carried out to produce mezcal under an artisanal process. The results of the physical-chemical parameters were: pH (7.3 - 7.5), organic matter (0.26% - 3.86%), total nitrogen (0.063% - 0.463%), electrical conductivity (0.25-0.40 dS m-1), exchange capacity cationic (17.05-41.93 cmol(+) kg-1), calcium (15.67 cmol(+) kg-1 - 48.90 cmol(+) kg-1) and magnesium (1.43 cmol(+) kg-1 - 11.21 cmol(+) kg-1) exchangeable, available phosphorus (0.3 mg kg-1 - 8.0 mg kg-1) calcium carbonate (1.4% - 32.2%), bulk density (1.0 g cm-3 - 1.88 g cm-3), texture (loam, clay loam and sandy clay loam) and color (light gray, gray, black and red). Spearman correlation analysis allowed to determine the relationship between the physical-chemical variables, and the principal components analysis to identify the variables that characterize each plot. The comparison of the analyzed parameters with the NOM-021-SEMARNAT-2000 standard showed that the soils have a neutral pH, with low content of organic matter, nitrogen and phosphorus, but with high content of calcium, magnesium, calcium carbonate and capacity cation exchange. These parameters allowed us to identify the limiting factors in the nutrition of wild maguey. Based on this information, nutrition strategies will be proposed that lead to increasing the accumulation of sugars in the mature maguey and, consequently, increasing the yield in the production of mezcal.
Application of Bokashi and Mountain Microorganisms in Corn Cultivation in Chenalhó, Chiapas
Organic manures and microbial biofertilizers have been positioned as agroecological alternatives with potential to improve soil fertility and food production sustainability, whose use reduces dependence on external inputs and contributes to environmental health. The objective of the present work is to evaluate the effect of mountain microorganisms (MM) and Bokashi (B) organic manure on soil fertility, growth and yield of corn crop in tornamil sowing (Nov 2023-June 2024) in the community of Campo Los Toros, Chenalhó, Chiapas. Four treatments were evaluated: T1 (control), T2 (MM), T3 (Bokashi) and T4 (MM+Bokashi) with a randomized block design with five replications. The MM treatment consisted of a consortium of bacteria, fungi and actinomycetes prepared with the reproduction and activation techniques and applied diluted to 50% with water by spraying soil near the plant stem, with a dose of 3 L 120 m-2, every 15 days until 120 days after planting. Bokashi was made with organic materials available in the community and applied at planting with a dose of 500 g mata-1. The corn growth in height, stem diameter and number of leaves during the vegetative period did not show significant differences among treatments (P ≥ 0.05). The microbial C-biomass content was 172.8% higher with MM than the control (P ≤ 0.05). Available phosphorus (Olsen) and mycorrhizal colonization percentage were 153.0 and 126.7% higher with MM+B treatment than the control. Grain yield was 82.4% higher with Bokashi than in the other treatments. Therefore, Bokashi proved to be a promising agricultural practice with potential to increase corn grain yield.
Black Carbon in Soils of the Monarch Butterfly Biosphere Reserve
Black Carbon (BC) in soils, also called pyrogenic carbon (C), is a material produced by the incomplete biomass combustion. In forests, fires are frequent events and part of their natural dynamics. These events incorporate BC into soil over time, and the ef fect is to retain nutrients on its porous surface, generating microbial activity that promotes high soil fertility for centuries; additionally, physical and chemical properties improve and increases water infiltration into the soil. The capacity of BC to be stored depends on the type of vegetation, topography and climate. The objective of the present research is to estimate Black Carbon in the soils of the Monarch Butterfly Biosphere Reserve (MBBR), making and georeferencing 37 soil profiles. The amount of BC in soil per hectare was determined from potassium permanganate (KMnO4). The spatial interpolation method was the inverse distance weighting (IDW: inverse distance weighted). The results obtained show that the total CN found in 37 profiles was 13 000 g ha-1. Profile 7 stored more CN with 2555 g ha-1, which indicates the forest fires that occurred in the RBMM, and in addition, the C that was not emitted to the atmosphere. The present research is the first in studies on Black Carbon in forest soils in Mexico, and the results corroborate that forest soils are carbon stores.
Leaf Water Potential of Three Browse Species of a Semiarid Ecosystem in Northern of Mexico
Climate change is a global phenomenon, its repercussions disrupt the functioning and integrity of ecosystems. The most marked impact of climate change is water stress, hence the importance of plant selection studies and their strategies based on the availability of water in the soil. The current study aimed to establish how the xylem water potential (Ψ) in three native shrubs, such as Condalia warnockii (Rhamnaceae), Flourensia cernua (Asteraceae), and Larrea tridentata (Zygophyllaceae), is influenced by soil water content, air temperature, relative humidity, and rainfall. The study was carried out in an area located the municipality of Galeana, state of Nuevo Leon. Using a Scholander pressure bomb, the Ψ were estimated at 15-day intervals between June 3 and November 18, 2018, in four dif ferent plants per species at 06:00 h (predawn) and 14:00 h (midday). At the wettest period, Ψ oscillated from -1.13 to -4.27 MPa (C. warnockii) at predawn. In contrast, at midday, L. tridentata and C. warnockii achieved the highest (-1.46 MPa) and lowest (-3.75 MPa) Ψ values, respectively. Soil water content at dif ferent soil depths, and relative humidity were significantly and positively correlated with Ψ at predawn of C. warnockii and F. cernua; whereas air temperature was correlated with F. cernua and L. tridentata at midday F. cernua and L. tridentata maintained high values in Ψ at predawn and midday under water stress conditions, so these species may be considered as drought tolerant species.
Physicochemical Analysis of Sulfide Groundwater in the Ejido Puente Negro in Coahuila, Mexico, Community Diagnosis and Proposal for Sulfide Desorption
The Ejido Puente Negro is characterized by the economic activities of farming and agriculture, despite having extensive periods of drought. Access to groundwater through dug wells is one of the main alternatives to meet the living needs of its inhabitants. However, poor practices have resulted in groundwater degradation, compromising phreatic mantles. The generation of treatment methods results in a good option to supply the population and ensure its quality. However, it is essential that residents are informed and have suf ficient knowledge to implement these practices. The present work shows a physicochemical study of groundwater from dif ferent wells located in the Ejido. A kinetic analysis of the desorption of sulfides was also carried out, concluding that their natural desorption is suf ficient to reduce more than 70% of their concentration in a period of 6 days. Additionally, the geology of the area is assessed in search of possible influence on groundwater contamination. Finally, a social study is presented about contaminated groundwater, the health implications involved in its consumption, and the understanding of purification and reuse processes.
Ef fect of Rhizoglomus intraradices, Stenotrophomonas rhizophila and Synthetic Fertilizer on Morpho-Productivity and Mineral Content in Cucumber
Arbuscular mycorrhizal fungi (AMF) and plant growth promoting rhizobacteria (PGPR) make the application of reduced doses of synthetic fertilizers more ef ficient, stimulating crop growth and productivity. The objective the present study is to evaluate the combined ef fect of Rhizoglomus intraradices, Stenotrophomonas rhizophila and a reduced dose of synthetic fertilizer on morpho-productivity and mineral content of cucumber under greenhouse conditions. A completely randomized design was used with the following treatments: 100% synthetic fertilization (SF); R. intraradices + SF 50 % (Ri+SF50%); S. rhizophila + SF 50% (Sr+SF50%), and R. intraradices + S. rhizophila + SF 50% (Ri+Sr+SF50%) using 200 plants per treatment. The following are calculated as: height (cm), stem diameter (mm), number of leaves and per plant: number of buds, male and female flowers, number of tendrils, greenness index (Iv), number and weight of fruits (g), total weight of fruit/plant (kg), yield (kg m-2), mineral content of N, P, K, Ca and Mn in %, colony forming units (CFU) and mycorrhizal colonization. The data were processed through an analysis of variance according to Tukey’s criterion at 95% confidence. The results indicate that plants with Ri+Sr+FS50% significantly increased (P ≤ 0.001) the height (24.18 cm), stem diameter (6.40 mm), number of leaves (18.35), tendrils (3.10), male flowers (0.4), greenness index (256.95), female flowers (8.90), number of fruits (8.6) and yield (15.92 kg m-2), compared to the application of 100% synthetic fertilizer (FS). The use of beneficial microorganisms in combination with a reduced dose of synthetic fertilizers increases cucumber productivity, therefore, it may constitute a sustainable alternative in agricultural systems, reducing production costs and decreasing environmental pollution, safeguarding human and animal health.
Ascophyllum nodosum in Optimizing Yield and Growth of Common Bean Under Water Deficit
Drought during the flowering period may cause severe reductions in yield and its components, as well as in growth or dry weithg accumulation in common bean plants (Phaseolus vulgaris L.). The objective of the present work is to determine the foliar application ef fect on a commercial biostimulant based on Ascophyllum nodosum extract on yield and its components, as well as plant growth through accumulated dry weight in the Azufrado Higuera bean variety under irrigation and drought conditions in a greenhouse. A randomized complete block design with a 2×2 factorial arrangement was used (two moisture levels: irrigation and drought; and two A. nodosum (with and without)) applicaton levels with four replicates. The variables evaluated were seed yield per plant (SYP), total biomass (TBM), number of normal pods per plant (NP), normal seeds per plant (NSP), leaf dry weight (LDW), stem dry weight (SDW), root dry weight (RDW), and root length (RL); SY and NP were 35 and 29% higher under irrigation than under drought. The A. nodosum application only af fected root growth, showing no ef fect on the plant aerial part. Under both irrigation and drought conditions with A. nodosum application, RDW was higher, while RL was similar under these conditions.
Influence of Forest Vegetation on Sediment Retention and Organic Carbon in Check Dams in Durango, Mexico
Vegetation removal, soil erodibility, and rain erosivity trigger the movement of soil particles and eventually the formation of gullies. To minimize the impacts of soil erosion, conservation and restoration dams are of ten constructed using stone, wood, or other materials aimed at slowing the movement of soil particles and promoting water infiltration. The performance of these dams was evaluated by estimating the volume and weight of retained soil retained in micro-watersheds with pine-oak forests in Durango, Mexico. Soil density and volume data were obtained to determine the weight of the sediments, as well as the volume of trees found in the catchment area of the check dam. An analysis of variance test with the Monte Carlo permutation technique was applied to evaluate the ef fectiveness of the dam construction material in retaining sediments, organic matter content, and carbon. Quantile regression analysis was performed to analyze the relationship between sediment weight and tree vegetation. Results indicate no significant dif ferences in sediment retention, but there are dif ferences in the amount of retained organic matter and carbon content according to the type of construction material. Wooden dams were the most ef fective compared to stone dams. The weight of retained soil has an inverse relationship with the volume of trees. Sites with higher tree vegetation density tend to better protect the soil and reduce the amount of sediment deposited in the dams. These results can help develop forest management plans compatible with less soil degradation.
Trace Metals in Soils from La Paz Valley (B.C.S., Mexico), Are they Contaminated?
Irrigation for agricultural purposes accounts for between 60 to 90% of the total water used for human activities, making it the largest consumer of freshwater on the planet. One of the most common practices for disposing of domestic wastewater has been its direct discharge, without treatment, into surface water bodies and the soil, resulting in public health issues and environmental problems, such as soil contamination. The aim of this study was to evaluate the contamination index of four soil samples in the La Paz Valley by analyzing the total concentration of trace element (cadmium, chromium, cooper, nickel, lead and zinc) to determinate contamination levels using the geoaccumulation index (Igeo). Additionally, four chemical variables were determined, organic matter (OM), total nitrogen, nitrates, and pH, to establish whether a relationship exists between the trace elements and the chemical variables. All trace element concentration ranges were below the total reference concentration according to the Canadian Of ficial Norm, and the Igeo values for the trace metals indicated uncontaminated concentrations. Furthermore, the average OM percentages were categorized as low and to medium across the four sites (0.72 to 1.70%), two sites recorded very low mean nitrogen concentration (0.05-0.08%), high nitrate concentrations were observed at site A (62.7 to 146 mg kg−1) and B (18.1 to 142.9 mg kg−1), and all the soils were alkaline (pH = 7.21 – 8.37). Significant positive correlations were found between OM vs Zn, Cu, and Ni, likely due to soil process that af fect the solubility and availability of these elements, or because these metals share common sources. Lastly, Cu and soil pH showed a significant positive correlation, influenced by several interaction factors. The varying irrigation characteristics at these four sites could af fect the chemical properties, but they do not appear to generate contamination, at least not in the elements analyzed in this study.
Growth and Accumulated Biomass in Coastal Dune Stabilizing Plants Biofertilized with Fosfonat®
Coastal dunes are dynamic ecosystems and vulnerable to erosion and invasion of species. For their conservation, it is necessary to implement strategies to recover native vegetation and rehabilitate the functioning of degraded areas. The growth and accumulation of biomass in Scaevola plumieri and Sophora tomentosa species native to the coastal dune were evaluated. An experiment was established in a forest nursery with two treatments (Consortium, beneficial microorganisms Fosfonat® and Control). For 90 days, every 15 days (six measurements), stem length, number of leaves, and at the end of the experiment, above-ground and underground biomass were measured and compared between treatments. The number of leaves was dif ferent between treatments af ter 45 days of seedling emergence. While the stem length of S. plumieri dif fers throughout the experiment and in S. tomentosa it dif fers significantly af ter 45 days of the experiment duration. The biomass accumulated in leaves and roots was higher in the seedlings of both species inoculated with the Consortium. Likewise, in this treatment, dif ferences were found in the length of the roots in both species. The results suggest that the application of beneficial microorganisms in the production of coastal dune stabilizing plants can contribute to improving the success of revegetation and ecological restoration programs in environments with limiting conditions for the establishment of plants such as dune soils coastal.
Substrates and Growth-Promoting Rhizobacteria in the Germination and Nursery Establishment of Passiflora edulis Sims (Passion Fruit)
The study evaluated the ef fect of dif ferent substrates and growth-promoting rhizobacteria on the germination and nursery development of Passiflora edulis Sims (passion fruit). The research was conducted at the Quevedo State Technical University, Ecuador, and was divided into two phases: germination and nursery growth. Four rhizobacteria were used (Serratia marcescens, Pseudomonas protegens, Enterobacter absuriae, and Acinetobacter calcoaceticus) at a concentration of 1 × 10⁸ CFU mL-1, in combination with three substrates (mountain soil with perlite, organic peat with perlite, and a mixture of both). E. absuriae achieved a germination rate of 51.11%, similar to the control, while P. protegens was particularly ef fective in promoting a leaf area of 12.92 cm², root length of 11.61 cm, and stem diameter of 1.33 millimeters. A. calcoaceticus, in mountain soil with perlite, promoted remarkable growth with 8 leaves per plant, a height of 14.72 cm, and a dry mass weight of 0.3 g. High catalase enzymatic activity was observed in treatments with E. absuriae, along with a significant increase in antioxidants in S. marcescens in the mountain soil with perlite substrate, accompanied by a bacterial density of 1.19 × 10⁸ CFU. The study highlights the potential of rhizobacteria to enhance the productivity and ef ficiency of P. edulis, emphasizing their value for commercial nursery applications and their contribution to more sustainable agriculture.
Impact of Hydroxyapatite Nanoparticles as a Biostimulant in Strawberry Crop
Biostimulation is the process by which plants respond and activate components of secondary metabolism, allowing the accumulation of biologically active substances in fruits and thereby improving their organoleptic and nutritional quality. In this research, the biostimulant ef fect of hydroxyapatite nanoparticles (nHAp) on strawberry crops was evaluated. The treatments included foliar application of increasing doses of nHAp; 500, 1000, 1500, 2000, and 2500 mg L-1, and a control (deionized water). Foliar application of nHAp on strawberries significantly improved yield, commercial quality, and content of bioactive compounds in the fruit. The dose of 500 mg L-¹ showed the best yield and fruit firmness, while higher doses increased bioactive compounds, although with a decreasing trend in productivity. These results show the potential of nHAp as an agricultural biostimulant, highlighting the need to determine optimal doses specific to each crop.
Pollution Risk in Agricultural Areas of the Huaquechula Sub-Basin
The impact of river water pollution on irrigated agricultural production systems is related to the accumulation of pollutants in the soil. The main objective of this study was to perform a spatial analysis of Nexapa River pollution and the risk it poses to agricultural lands near the river. The WASP model was used to simulate the transport and concentration of total nitrogen, nitrate, total phosphorus, cadmium, chromium, and lead in the Nexapa River. A spatial analysis was performed using the model estimates and the land-use and vegetation map to identify the agricultural areas most at risk of contamination from wastewater discharges. The highest pollutant concentrations estimated with the model were: total nitrogen (20.04 mg L-1), nitrate (7.03 mg L-1), total phosphorus (2.80 mg L-1), cadmium (0.002 mg L-1), chromium (0.085 mg L-1), and lead (0.009 mg L-1). Two areas of greatest risk to contamination associated with the use of water from the Nexapa River were identified: one in southern Atlixco and the other in northern and southern Izúcar de Matamoros. A limitation of the modeling was the unavailability of point source discharge data and the lack of access to discharge facilities for wastewater sampling; therefore, samples were taken at the river discharge sites. This study is pioneering in river modeling in the Puebla Valley. It is concluded that the WASP model is a useful tool for analyzing the spatial and temporal dynamics of pollutant concentrations in the Nexapa River and for predicting potential contamination risk areas and the need for intervention measures in the Huaquechula sub-basin.
Supervised Classification for Mapping Forage Maize Using Remote Sensing in the Laguna Region, Mexico
Supervised classification is a technique that identifies spectrally similar regions using training samples extracted from a satellite image. The most used agricultural land cover classification algorithms include minimum distance, maximum likelihood, spectral angle mapper, and Random Forest. This study evaluated the performance of these algorithms in identifying, mapping, and quantifying the area cultivated with forage maize in irrigation modules X and XII of Irrigation District 017 in the Laguna Region, a crop of high economic importance. Sentinel-2 satellite imagery was used, acquired on three dates corresponding to key phenological stages of forage maize, from tasseling to the reproductive milky grain stage. The Random Forest algorithm with 100 decision trees performed best, achieving the highest overall accuracy and Kappa index scores in both irrigation modules. Module X presented overall accuracy values ​​of 79.1% and a Kappa index of 0.63. On the other hand, Module XII recorded values ​​of 87.4% overall accuracy and 0.79 Kappa index. The highest accuracies were obtained with the image from June 11, 2021 (Julian Day 162), when phenological and coverage dif ferences favored the separation of the crops. Forage maize covered the largest surface area in the study region, reaching 44% of the total surface. The classification of forage maize proved to be the most reliable compared to the other evaluated classes in both modules. The precise identification, spatially and temporally, of forage maize allows for the generation of updated and reliable inventories, ef fectively contributing to decision-making in crop planning and management, as well as in the management of water resources.
Response to Fertilization of ‘Marrs’ Orange Trees with Symptoms Associated with CTV and HLB
The incidence of citrus tristeza virus (CTV) and Huanglongbing (HLB) are associated with nutritional imbalance, the presence of symptoms in the tree canopy and low orange production. Balanced fertilization is used as an alternative to mitigate damage. The objective of our study was to assess the fertilization ef fects in nutritional status of ‘Marrs’ orange trees with symptoms associated with CTV and HLB, and the mineral composition of the fruits. The study was conducted of August 2019 to December 2020 in a commercial plantation with six-year-old trees. Before fertilization, implementing the DOP indices carried out a nutritional diagnosis. The experimental design used was random blocks in split plot arrangement, with three replications. The variables were: nutritional status of the tree, nutritional deficiencies in the leaf, and mineral composition of the fruit. The DOP method detected that Zn > Mn > Cu > B > P > Mg > Fe > K > N > S were the most required minerals; indices for N, S, Zn, and Mn show a tendency to decrease in trees with mild and advanced symptoms. Chemical foliar fertilization promoted the development of vegetative shoots without nutritional deficiencies during flowering and fruit set. However, an atypical drought during fruiting af fected the trees’ response to the treatments. The trees presented symptoms of Zn and Mn deficiencies, combined with asymmetric chlorotic mottling in the leaf blade associated with CTV and HLB. Overall, the mineral composition of the fruits was deficient except for P, Ca, and Cu.
Experimental Inoculants and Selection of Ef ficient Native Microorganisms in Slender Black Beans
The use of biofertilizers made with native soil microorganisms has shown an ef fectiveness in agricultural production similar to that obtained with mineral fertilization. The objective of our research was to evaluate the ef fectiveness of dif ferent experimental inocula based on arbuscular mycorrhizal fungi (HMA) and native nitrogen-fixing bacteria on slender black beans in a greenhouse. The experiment was established in April 2023 with biological material extracted from irrigated and rainfed soils intended for the cultivation of slender black beans in Santa Cruz Lachixolana, Santo Domingo Tlaltinango and Santiago Suchilquitongo, Oaxaca. The evaluation began eight days af ter germination, for eight weeks. For the evaluation of HMA ef fectiveness, the study variables were: RAS index (ratio dry aerial biomass (g)/dry root biomass (g)), relative height growth rate (TRCA, cm/week), rate relative growth in diameter (TRCD, mm/week), leaf area (AF, cm2) and mycorrhizal colonization (MIC, %). To evaluate the ef fectiveness of rhizobia, the variable nodules per plant (NOD, number) was added. The data were analyzed in the SAS version 9.4® sof tware, using an analysis of variance, Bartlett’s homogeneity tests, and separation of means with Tukey test (P ≤ 0.05). The variables evaluated in the HMA inocula recorded highly significant statistical dif ferences between treatments (P ≤ 0.01), the rhizobia inocula evaluated showed highly significant dif ferences (P ≤ 0.01) for the NOD and AF variables. The use of inocula made with native HMA promotes an increase in TRCA, TRCD, AF and MIC by 43, 29, 66 and 60%, respectively, based on the control treatment. The use of rhizobia inocula used as biofertilizers increased the NOD values ​​from 7 to 43 nodules/plant and AF by 82%, both with regards to the control treatment.
Influence of Arbuscular Mycorrhizal Fungi and Vermicompost on the Growth of Mexican Lemon (Citrus aurantifolia Swingle)
Mexican lime (Citrus aurantifolia Swingle) production is limited by the intensive use of chemical fertilizers. In search of sustainable and ef ficient alternatives, in our study we evaluated the application of vermicompost and arbuscular mycorrhizal fungi (AMF) on the growth of lime seedlings. The evaluation compared chemical fertilization (C), vermicompost (V), Glomus clarum AMF (G), an AMF consortium (C), a combination of vermicompost + AMF (GV and GVC), and a control (S). Plant height, stem diameter, leaf number, leaf area, fresh and dry weight of leaves and roots, concentrations of N, P, K, Ca, Mg, Fe, Cu, and Zn in plant tissues, chlorophyll content, photosynthetic rate, stomatal conductance, spore count, and mycorrhizal colonization were evaluated af ter 270 days. The results revealed a significant synergistic ef fect (P ≤ 0.05) between vermicompost application and AMF inoculation. Vermicompost-treated plants showed a 50% increase in leaf number compared to the control and a 17% increase compared to chemical fertilization; fresh biomass also improved (57 over S and 17% over F). Application of Glomus clarum and the AMF consortium promoted higher N, P, and Cu contents in leaf tissue, as well as a higher photosynthetic rate. Combined vermicompost and AMF treatments significantly improved plant height (56 and 43% for GV compared to S and F, respectively), root fresh weight (59 and 33%), leaf and root dry weight (48-67, 7-31%, respectively), and increased leaf tissue levels of N (45, 29%), P (38, 34%), and Zn (143, 206%); as well as higher chlorophyll a (9, 6.5%) and total chlorophyll (12.5, 10%) contents compared to the control and chemical fertilization. Our findings suggest that the combination of vermicompost and AMF represents a promising strategy for optimizing sustainable Mexican lime production.
Use of Organic Fertilizers to Preserve the Quality of Lactuca sativa L. During Post-Harvest Storage
One of the most important and widely produced crops in the world is lettuce (Lactuca sativa L.), due to its high nutritional value and organoleptic properties. However, the abuse of chemical fertilizers for its production results in soil erosion and aquifers pollution. The purpose of our study was to evaluate the ef fect of organic fertilizers on the post-harvest quality of lettuce (Lactuca sativa L.) at 5 °C. A completely randomized experimental design was developed, involving romaine lettuces (Lactuca sativa L. var. longifolia) grown under 3 dif ferent treatments: Chemical fertilizer (FQ); cof fee pulp vermicompost (LC); and sheep manure vermicompost (LHB), with 10 replicates of each treatment. Af ter harvest, the lettuces were stored at 5±1 °C. Selected quality parameters of total soluble solids (TSS), pH, color, total phenolic compounds, total flavonoids, in vitro antioxidant activity, and polyphenol oxidase (PPO) activity were assessed on days 0, 5 and 10 of storage. The results showed that by the end of storage, LC lettuces had the highest luminosity and chromaticity values, as well as total phenolic compounds (0.9 mg EAG g-1), total flavonoids (0.8 mg CE g-1), DPPH antioxidant activity (4.1 uET g-1) and FRAP antioxidant activity (6.9 uET g-1 μTE g-1). LHB lettuces showed the lowest PPO activity. These results show evidence that the use of organic fertilizers, especially cof fee pulp vermicompost, improves the postharvest quality of lettuce and maintains its shelf-life for up to 10 days of storage at 5±1 °C, which can contribute to prevent spoilage and wastes, as well as to substitute the use of inorganic fertilizers, with their detrimental environmental ef fects.
Influence of Three Design Factors and Seasonality on the Removal of Three Drugs by Treatment Wetlands
Wastewater use in agriculture represents a global problem because of the presence of many organic micropollutants, including non-steroidal anti-inflammatory drugs (NSAIDs). These substances have been reported to harm plant development and other biological processes in crops. Therefore, the objective of the present study is to evaluate the ef fect of three design factors and seasonality on removal ef ficiency of three drugs by wetlands treatments. Fif teen systems designed according to Latin square were constructed using the following input variables: plant type (Pl), hydraulic retention time (HRT), and type of porous medium (PM), and the output variables were the removal ef ficiencies of naproxen, ibuprofen, and diclofenac to evaluate the ef fect of seasonality. Fif teen samples were grouped into three time periods, and the removal ef ficiencies were statistically compared. The maximum removal percentages of 85.3, 79.0, and 81.8% were obtained for naproxen, ibuprofen, and diclofenac, respectively. Regarding the design factors, only HRT showed a significant ef fect on naproxen removal; however, neither MP nor Pl showed statistically significant variation. In the case of seasonality, better system performance was observed during the warmer period. Only HRT had a significant ef fect on removal ef ficiency, achieving ef ficiencies higher than 50%, which positions these systems as ef fective alternatives for removing these compounds.
Ef fect of Nitrogen Forms in the Vegetative Development of Three Pitahaya Species
Pitaya cultivation has gained global popularity due to its high profitability, exotic appearance, and nutritional properties. However, limited information exists on nutrient management and nitrogen forms that promote vegetative growth. The objective of the present research is to evaluate the ef fect of nitrogen (nitrate, ammonium, and combined) form in the nutrient solution on the vegetative development and nutritional status of three pitahaya species (Selenicereus undatus, Selenicereus sp., and Selenicereus ocamponis). The study was conducted in a greenhouse in Santa Cruz Tacache de Mina, Oaxaca, Mexico. A completely randomized design was proposed with three pitahaya species, five NH4+/NO3- ratios, and four replicates per treatment. Growth characteristics and nutrimental content in plant stems were evaluated by using analysis of variance, Tukey’s honest significant dif ference mean separation test, and factorial analyses by species and NH4+/NO3- ratio. Non-parametric Kruskal-Wallis tests were also considered when necessary. The results highlighted that in Selenicereus sp., rib diameter of the cutting and shoot increased with the 0/100 ratio; plant height, number of shoots, fresh and dry aerial matter, and root length were promoted with the 100/0 ratio. Nutritional concentration was favored in Selenicereus undatus with the 50/50 ratio, Selenicereus sp. with 100/0 ratio, and Selenicereus ocamponis with 75/25 ratio. Selenicereus sp. developed favorably in the greenhouse with ammonium nitrogen form. In conclusion, nitrogen form combinations increase, in general, three pitahaya species vegetative development.
Phosphorus Adsorption and Availability from Two Phosphate Sources in Vertisol in Northern Mexico
Phosphorus (P) is an essential nutrient for plant development; its study in soil is fundamental to optimize phosphate fertilizer management based on the specific soil characteristics and production systems. The present study aims to determine the maximum P adsorption capacity in Vertisol and evaluate the behavior of two phosphate fertilizers. Using Langmuir isotherm, the maximum P adsorption capacity in soil was 1080 mg kg–¹ with calcium triple superphosphate (SFT) and 1030 mg kg–¹ with phosphoric acid (H3PO4). Of the P applied as SFT, 30% was present as P-Ca and 28% as soluble P, while with H3PO4 these percentages were 40 and 31%, respectively. The two P sources showed dif ferentiated behavior when applied to soil. The P derived from H3PO4 was released quickly, reaching concentrations more than double of those obtained from SFT; however, at 24 hours post-application, regardless of the source or dose, 94% of the applied P was adsorbed, indicating the high adsorption capacity of the Vertisol soil. H3PO4 showed a greater initial availability of P, which could be advantageous in intensive production systems. In contrast, SFT shows a more gradual release, making it a viable option for base fertilization. Phosphorus adsorption capacity and availability in soil determine the selection of the most suitable phosphate fertilizer according to the production system.
Two Sprinkler Models in Performance, Quality and Ef ficiency of Water Use in Potato Crops (Solanum tuberosum L.)
The surface area of irrigated potatoes harvested in Mexico is 68 000 ha, of which 64% are irrigated and 36% rainfed with an average yield of 27.4 Mg ha-1 and an economic impact of 11 000 million pesos per year, placing this crop among the five main ones in the country. In the last 10 years, the use of fixed sprinkler systems has increased exponentially, mainly in northwestern irrigation districts. Nonetheless, a lack of scientific information exists on their ef fect on yield, quality, and irrigation water use. Therefore, the objective of the present research is to determine the ef fect of Naan Dan 5022 (A1) and Xcell Wobbler Senninger (A2) sprinklers on water yield, quality and use in Fiana variety of potato crop. The study was performed in Sinaloa, Mexico, on a representative soil of the area, establishing three treatments (T) in a strip of land of 0.12 ha: T1 (A1) sprinkler and T2 (A2) sprinkler. The variables measured were operating pressure, irrigation depth, irrigation uniformity, application ef ficiency, biomass, Normalized Dif ference Vegetation Index (NDVI), yield and tuber quality; the last three variables were subjected to an analysis of variance and a mean test. The estimated yield for the best treatment was 42 Mg ha-1 using Xcell Wobbler sprinkler. At the end of this project, the use of Xcell Wobbler sprinkler is recommended due to its operation reliability at lower pressures and, in general, adapting to specific operating demands of the study area and improving potato crop production in the northern state of Sinaloa.
Arbuscular Mycorrhizal Fungi and Microbial Activity in Mine Tailings: Potential to Promote Plant Growth Under Stress Conditions
Mining facilities release considerable amounts of toxic elements into the environment, which persist for long periods of time, their remediation is necessary for human health. Arbuscular mycorrhizal symbiosis improves plant resistance to biotic and abiotic stress, and aids in the adsorption of nutrients under heavy metal stress. The present study aims to determine the mycotrophic plants established in mine tailings, their relationship with microbial activity, and with the physicochemical characteristics of mine tailings. A physical, chemical, and plant characterization of the mine tailings was carried out, and the percentage of mycorrhizal colonization, microbial activity, and concentrations of lead, cadmium, nickel, and zinc were evaluated. The results showed that the mine tailings had neutral pH, very low organic matter content, medium nitrogen content, high phosphorus and potassium content, low calcium availability, and medium magnesium availability. Eleven species were identified from nine families, four species were shrubs, three species were trees, three species were herbaceous, and one species was cactus; 10 of them are perennial. Colonization percentages ranged from 11 to 91%, and microbial activity values ranged from 6 to 42 µg p-nitrophenol g-1 dry soil. Concentrations of 10.63 mg kg-1 for lead, 0.58 mg kg-1 for cadmium, 0.20 mg kg-1 for nickel, and 36.21 mg kg-1 for zinc were found. The data obtained showed that the plants were colonized by arbuscular mycorrhizal fungi (AMF) and the rhizosphere zone had a wide range of microbial activity that could allow them to tolerate the stress conditions present in mine tailings.
Arbuscular Mycorrhizal Fungi from a Semiarid Agroforestry System Promote Growth and Nutrition of Lettuce
Arbuscular mycorrhizal fungi (AMF) promote the development of wild and cultivated plants and are, therefore, critical in agroforestry systems. In our study, we evaluated the ef fectiveness of three inocula of arbuscular mycorrhizal fungi of AMF from three dif ferent land uses: vegetation islands and open areas of agroforestry system “milpa-chichipera”, and xeric scrub on the growth and nutrition of lettuce plants (Lactuca sativa L.) at semiarid Tehuacan-Cuicatlan Valley, Puebla-Oaxaca, Mexico. A sterilized substrate was prepared based on a 50/50 (v/v) mixture of soil and silica sand. Three inoculation treatments were established with 50 g of soil inoculum which included AMF from the three land uses and a control without inoculation, with five replicates. The plants were grown for three months, and at the end of the experimental period, the aerial part was harvested to evaluate fresh and dry weight, leaf area and contents of water, leaf chlorophyll, N and P in plant. All inocula favored the growth and nutrition of lettuce compared to the control. However, inoculated plants with AMF from vegetation islands and open areas of the agroforestry system had a better response than those inoculated with AMF from xeric scrub. Likewise, the three inocula increased the chlorophyll of the leaves in the plants; however, these were higher in inoculated plants with AMF from the vegetation islands of the agroforestry system and xeric scrub. Additionally, tissue P and N contents were higher in inoculated plants with AMF from agroforestry system. The inocula from agroforestry system were more ef fective for lettuce crop than the inoculum from xeric scrub; however, all three inocula could be potential mycorrhizal biofertilizers in this semiarid ecosystem.
Associative Assessment of the Economic Impact of Water Stress on Agricultural Production in Northeastern Mexico Using Indicators
Irrigation District 025, located in northeastern Mexico, faces adverse climatic conditions characterized by a dry climate and insufficient rainfall for optimal agricultural development. This situation has been exacerbated by Climate Change (CC), which has significantly reduced agricultural yields. Our study, classified as empirical with an associative strategy, aimed to evaluate the economic impact of water stress on agricultural production using three key indicators: the Economic Value of the Water Footprint (HHvalor), Irrigation Supply Efficiency (ESRhh), and Agricultural Production Value (Vp). The non-experimental methodology included the analysis of water footprints, water productivity, current irrigation conditions, and agricultural and hydrometric statistics, associated with two scenarios: an ideal scenario without water stress (Baseline, LB) and a scenario with water stress (Real Condition, RC). Meteorological data were generated using WXGEN and processed with FAO’s CROPWAT 8.0 software to calculate irrigation requirements for the main crops. The results showed that the highest economic impact of water stress was obtained with HHvalor ($ 798 110 647.64), followed by ESRhh ($ 215 410 806.25) and Vp ($ 72 341 989.32), with an average impact of $ 361 223 351.00. The main limitations of the study included the lack of directly measured meteorological and physiological data for the crops. Nevertheless, the developed indicators and methodology provide effective tools to quantify and mitigate economic losses resulting from water stress, contributing to more efficient water management in agriculture. In conclusion, our main finding was that HHvalor allows for a comprehensive assessment of the economic impact of water stress on irrigated agricultural production, as it incorporates both the water footprints of crops and their intrinsic economic value.
Analysis of Land Cover and Land Use in the Lower Usumacinta River Basin Using Remote Sensing Techniques
The drivers of land use change at various scales pose a threat to the stability of tropical ecosystems, af fecting both biodiversity and essential ecosystem services. These changes are particularly critical in areas such as the Lower Usumacinta River Basin (LURB), a region of ecological and cultural value. In this context, our study aims to classify land cover and land use (LCLU) in the LURB using Landsat 8 OLI satellite imagery. Two classification methods were employed: the ISODATA algorithm for unsupervised classification (USC) and the Maximum Likelihood Classification (MLC) algorithm for supervised classification (SC). The unsupervised classification grouped the pixels based on spectral distance, identifying four general classes: wetlands, anthropogenic activities, tree vegetation, and water bodies, with a moderate accuracy of 67% and a kappa index of 0.51. In contrast, the supervised classification, using 948 training points and auxiliary data derived from the Normalized Dif ference Vegetation Index (NDVI) and the Digital Elevation Model (DEM), provided more detailed mapping, discriminating specific classes such as agriculture (41.46%), wetlands (21.17%), commercial forest plantations (4.09%), and urban areas (0.56%), achieving a kappa index of 0.90, validated with 330 ground control points. Our results show that the integration of NDVI and DEM data significantly improved spectral discrimination of tropical forest cover and wetlands, while the unsupervised classification exhibited limitations in dif ferentiating specific classes such as tropical forests, flooded forests, and oil palm plantations. Our findings highlight the importance of using up-to-date satellite imagery, along with auxiliary data and robust algorithms, to achieve more accurate LCLU classification, which is essential for land planning, natural resource management, and biodiversity conservation in the LURB.
Evaluation of Bell Pepper Growth and Yield at two Organic Fertilizer Production Sites
Among the options for improving Capsicum annuum L., fertilization increases nutrient availability. The objective was to evaluate eight bell pepper genotypes with two study factors: 1) greenhouse, 2) open field. The fertilization sources applied as treatments were: 1) solarized manure, 2) vermicompost, 3) poultry manure, and a control with Steiner solutions. The results show a significant difference between genotypes and fertilizers, mainly expressed in growth. Fruit weight for genotype 1 with cow manure or poultry manure, genotype 5 with cow manure or vermicompost and genotype 6 with chicken manure showed the best interactions with 81.5, 118.96, 75.63, 82.7 and 81.49 g. Therefore, there was a significant difference in the response of the genes involved in the control of the characteristics to fertilizers.
Hydrophobic Ef fects in Soils Burned at Dif ferent Intensities
The high temperatures to which the soil is exposed during a forest fire generate diverse ef fects that af fect soil quality. The present investigation analyzes the chemical properties of four land use systems of a Vertisol exposed to dif ferent burning intensities (205, 200, 400, 750 and 900 °C) with emphasis on the property of hydrophobicity. The determination of soil water repellency persistence was carried out through the water drop penetration time (WDPT) methodology, pH by the AS-23 method of the NOM-021-RECNAT-2000, organic matter (OM) by the Walkley and modified Black method and electrical conductivity (EC) by the 1:5 soil - water ratio method. The results indicate that the increase in temperature significantly decreased hydrophobicity in the four soil use systems; On the other hand, the hydrogen potential (pH) and EC showed an increase. These values are associated with the combustion of OM, which generated ash that contributes oxides, basic cations and substances of a hydrophilic nature.
Quality of Drinking Water in the Rural Peripheral Areas of Quevedo Canton, Ecuador
The quality of drinking water is a crucial aspect for the health and well-being of any community, especially in the rural peripheral areas of Quevedo canton, Ecuador, where the drinking water supply infrastructure is deficient and exposure to contaminants is high. In our study we aim to conduct a comprehensive analysis of drinking water quality. Five representative localities in Quevedo canton were selected for the evaluation of microbial load and analysis of total coliforms, soil texture, soil pH, and the content of nitrates, nitrites, copper, and chromium in the water. Our results showed significant variations in water and soil quality among the localities. The microbial load and total coliform counts were highest in SCR 3, indicating a possible local contamination source. The soil texture varied, with a predominance of sandy texture in SCR 2 and SCR 3, which af fects water retention and nutrient availability. Soil pH values ranged from 6.0 to 7.0, with SCR 3 presenting the lowest pH. Nitrate concentration was highest in SCR 2 (20 mg L-1), while nitrites were highest in ESP 2 (0.12 mg L-1). Copper levels varied, being highest in AGR (18 mg L-1), lastly, hexavalent chromium levels were highest in SCR 2 (0.075 mg L-1). These variations in water and soil quality have significant implications for public health and agricultural productivity. Sources of contamination were identified in our study, hence, we propose mitigation measures to improve water quality, promote public health, and support sustainable agricultural development in the rural communities of Quevedo.
Hydroxyapatite Nanoparticles as an Ef fective Fertilizer in Sunflower Crop Quality
Nanotechnology involves manipulating materials at the atomic or molecular scale, particularly those smaller than 100 nm, which display unique properties due to quantum ef fects and a high surface area-to-volume ratio. In agriculture, nanoparticles (NPs) enhance fertilizer and pesticide ef ficiency, improve crop yield, and enable early detection and treatment of plant diseases. This study evaluated the ef fect of hydroxyapatite nanoparticles (HANPs) as a foliar fertilizer on sunflower (Helianthus annuus) crop quality, alongside vermicompost, chemical fertilizer, and biofertilizer applied to soil. The HANPs ranged from 10 to 45 nm, with 53.1% between 15 and 25 nm, predominantly rod-shaped. Agronomic variables (plant height, stem and disc diameter) and phytochemical properties of sunflower oil (total phenolic compounds, flavonoid content, antioxidant capacity) were analyzed under three HANP doses: 2000, 4000, and 6000 mg L-1. Results showed that vermicompost and chemical fertilizer had no significant dif ferences in plant height, whereas biofertilizer (299.6 and 258.6 cm) dif fered significantly from the control. Phytochemical analyses yielded 17.9-35.4 mg GAE mL-1 of phenolic compounds, 29.8-60.7 mg QE mL-1 of flavonoids, and 18024.60-25159.52 μM TE mL-1 of antioxidant activity across treatments. The aim was to assess HANPs’ influence on sunflower development and the antioxidant profile of its oil. Among the doses tested, 4000 mg L-1 proved optimal for enhancing total phenolic and flavonoid content, as well as antioxidant capacity, indicating its potential for improving the nutritional and functional quality of sunflower oil.
Folic Acid (vitamin B9) or Inoculation with Beneficial Microbes Enhances Plant Growth in Phaseolus vulgaris L.
Folic acid (vitamin B9) plays a crucial role in chlorophyll synthesis, and its exogenous application to plants could positively influence the Dark Green Color Index (DGCI) and plant growth. This study investigated how vitamin B9 supplementation could affect the growth of inoculated Phaseolus vulgaris L. (Fabaceae) and its symbiont. The inoculant used contained both arbuscular mycorrhizal fungi (AMF) and bacteria. We measured DGCI in leaves, plant growth variables and AMF colonization 35 days after seeding. Our results showed that in P. vulgaris treated with vitamin B9, both plant growth and DGCI increased compared to controls. However, the addition of vitamin B9 to P. vulgaris plants, inoculated with a mixture of AM fungi and bacteria, did not further increase plant growth, suggesting that inoculated plants are not limited by vitamin B9. This study is the first to highlight the role of vitamin B9 in inoculated P. vulgaris plants. Independently, both vitamin B9 amendment and inoculation with beneficial microbes increased the measured variables; though, their combined effect was not additive. Therefore, our results suggest that the addition of vitamin B9 does not further increase the measured variables when the plants are inoculated with a mixed AMF and bacterial inoculant.
Capsicum annuum L. Response to Highly Diluted Bioactive Compounds Application in Germination and Initial Growth Under Saline Conditions
In line with the green economy concept, food using natural products is gaining importance worldwide. Thus, the present study aims to evaluate the ef fect of Natrum muriaticum (NaM) and Silicea Terra (SiT) as salt stress (NaCl) mitigators on Capsicum annuum L. germination and initial seedling growth of two chili varieties. The experiment was performed under controlled conditions, using a completely randomized design with a factorial arrangement of (2A × 3B × 5C), where factor A is the two varieties (Santa Fe and Jalapeño M); factor B is the three levels of NaCl (0, 50 and 100 mM) and factor C is the centesimal dynamizations (CH) of the highly diluted bioactive compounds (HDBC) Natrum muriaticum (NaM): NaM-7CH, NaM-13CH and Silicea terra (SiT): SiT-7CH, SiT-13CH. Distilled water (DW) was used as a control treatment for a total of 30 treatments with four replicates each. The response variables were the germination percentage (GP), germination rate (GR), and, af ter 14 days, the height of the seedlings (HS), radicle length (RL), fresh and dry radicle biomass, and aerial part. Analysis of variance and multiple comparisons of means were performed (Tukey HSD P ≤ 0.05). The results show that NaM-7CH and SiT-7CH applications significantly increased GP, RL, and radicle and aerial fresh and dry biomass parts. The highest response was recorded in RL with NaM-7CH treatment, 57.8% in Jalapeño M variety, and 86.3% in Santa Fe variety with respect to the control treatment seedlings without HDBC (DW). In general, a NaM anti-stress ef fect was observed, demonstrating its ef fectiveness and great potential in sustainable organic agriculture as a low-cost alternative to mitigate the negative ef fects of abiotic stress.
Native Bacteria as a Sustainable Alternative for Serrano Pepper Yield
The chili fruit (Capsicum annuum L.) is widely consumed for its rich nutrient content and health benefits, making it an essential component of a healthy diet. Despite these benefits, conventional production systems can cause ecological issues, including greenhouse gas emissions and increased soil salinity. This highlights the need for sustainable farming practices. This research evaluated the impact of bioinoculation with native strains of Bacillus velezensis, Bacillus subtilis, and Azospirillum brasilensis, on the yield and bioactive compound content of serrano chili fruits in the Comarca Lagunera. Bioinoculation with native strains, combined with a 50% reduction in chemical fertilization, produced similar results to those obtained with full chemical fertilization in terms of fruit weight with 6.07 g and 6.15 g respectively, in terms of yield 33 Mg ha-1 and 32 Mg ha-1, amount of phenols 6.27 mg AG 100 g-1 BF and 6.56 mg AG 100 g-1, vitamin C 0.82 mg g-1 BF and 1.10 mg g-1 BF while for capsaicin 269.25 µg g-1 of BS and 274.75 µg g-1 of BS in the same order. The results demonstrate that this methodology can be a sustainable alternative, allowing for a decrease in chemical fertilizer use while promoting soil health through the bioinoculation of native bacteria, which are ef fective when adapted to abiotic stress factors.
Evaluation of precipitation data from CHIRPS images in dry and tropical (San Luis Potosi) and temperate (Mexico State) basins in Mexico
Hydrological modeling requires precipitation data as a basic input since it represents the primary water source entering the hydrological system. These data are mainly obtained from weather stations, but in many cases, the number of stations is low, and may have missing data, leading to errors in modeling. With technological advances in remote sensing, freely accessible satellite precipitation data are gaining importance as a potential input for hydrological modeling. Thus, the objective of the present research is to evaluate two sources of precipitation data: weather stations and CHIRPS (Climate Hazards Center InfraRed Precipitaion Station) imagery. Both sources were compared across three basins with contrasting climates (arid, temperate, and tropical). The analysis was based on statistical measures, such as Spearman’s correlation coef ficient ρ (rho), Root Mean Square Error (RMSE), and the Wilcoxon test to detect correlations and statistical dif ferences. The results revealed a positive and significant correlation (P < 0.05) between both data sources across the three basins, though with variations depending on the climate type. The RMSE (< 21 mm) were recorded in temperate and arid regions, while in the tropical region, CHIRPS imagery underestimated precipitation. The greatest similarity (P > 0.05) between the two sources was found in the temperate region, which suggests that CHIRPS imagery is a viable alternative to weather stations for hydrological modeling, especially in temperate climate basins.
Phenotypic Plasticity Under Salt Stress in Legume Grasses
The present research investigated the phenotypic plasticity of pasture legumes subjected to salinity stress in a semi-controlled environment. Two salinity levels were tested (0.02 dS m-¹ and 10 dS m-¹) to assess their impact on aerial and root biomass accumulation, as well as histological characteristics and nitrogen, sodium, and potassium accumulation. Findings indicated a detrimental salinity ef fect on all measured traits in the legumes examined. Species such as Sesbania rostrata, Leucaena leucocephala, Clitoria ternatea, Centrosema pubescens, and Canavalia ensiformis notably exhibited significant phenotypic adaptability to salt stress across the parameters evaluated. Aerial and root dry matter, along with nitrogen accumulation, demonstrated the highest phenotypic plasticity indices in response to salinity. Additionally, the consistent sodium accumulation observed suggests that these species may employ sodium exclusion as a mechanism to cope with salt stress. Future research is warranted to explore photosynthesis and other growth stages, which would enhance understanding the phenotypic plasticity of these legumes under saline conditions.
Morphological and Phenological Response of Pepper Plants to Selenium Nanoparticles Supplementation
Pepper cultivation represents an agricultural and economically important activity for the regions of Ecuador, given the increase in consumption and search for nutritional quality products with good appearance. Emerging nanotechnology applied to agriculture is seen as a safe and ef fective way to take advantage of resources, either as a nanofertilizer or as a biostimulant. Thus, the objective of the present study is to evaluate foliar selenium nanoparticle (nSe) application impact on pepper crop morphology, phenology, and yield, as well as the profitability index of nanotechnology applicability in this culture system. The nSe treatments consist of foliar sprays at 10, 15 and 20 mg L−1 and a control treatment. Morphological indices, fruit quality, and benefit/cost ratio of the treatments were evaluated. The results suggest a positive nSe impact on jalapeño pepper plants, showing increases in plant growth (>40%), improvement in fruit physical quality (>20%), and a yield promotion by more than 30%. In addition, a higher net income than conventional pepper production has shown a benefit/cost ratio of 4.91 when applying 20 mg L−1 of nSe. On the other hand, a precocity was noted in the plants, since they had significantly earlier blooms in the nSe treatments.
Beneficial Microorganisms and Liquid Compost Enriched with Silicon: Alternatives for Agroecological Rice Crop Production
The use of beneficial microorganisms and the application of liquid compost enriched with silicon constitute sustainable agroecological practices in rice (Oryza sativa) cultivation. The objective of this research was to evaluate the ef fect of agroecological practices and the use of silicon on the variables days to flowering and percentage of sterility of the panicle in the INIAP-14 rice crop in clay loam soil, at the State Technical University of Quevedo (UTEQ), Ecuador. The treatments evaluated consisted of T1= control without application; T2= Buf fago® insecticide (0.5 L ha-1); T3=, strain Ag, at 1×109 CFU mL-1; T4= liquid compost enriched with potassium silicate (K4SiO4) (10 L Azotobacter chroococum ha-1); T5= Metarhizium anisopliae, strain 45 (1. 2 L ha-1) and T6= combination of A. chroococum + liquid compost enriched with K4SiO4 and M. anisopliae, in a completely randomized design with four replications. The analysis of variance showed significant dif ferences for both days to flowering and percent sterility. The results showed that treatment T6 presented the lowest significant values in days to flowering (72.8 days) and percentage of panicle sterility (9.0%) according to the Scott and Knott test. A non-linear sigmoidal relationship was found by Hill’s model between days to flowering and the percentage of panicle sterility, which indicates that for this cultivar and in these soil and climatic conditions, the lengthening of days to flowering increases the percentage of panicle sterility, suggesting that the application of A. chroococum + liquid compost enriched with K4SiO4 and M. anisopliae could be ef fective in decreasing the percentage of sterility of the rice panicle, thus increasing the yield of the crop developed with bioinputs accepted in agroecological practices.
Symbiotic Interaction Between Common Bean Genotypes and (Rhizobium spp.) Strains
The legume-Rhizobium association is a high-ef ficiency process in biological nitrogen fixation that can supply up to 90% of the nitrogen needed in some species. To evaluate the symbiotic response of 10 cultivated and wild bean genotypes inoculated with 10 strains of Rhizobium isolated from domesticated and wild bean nodules, seedlings were grown and inoculated under greenhouse conditions in Zapopan, Jalisco, Mexico. At the beginning of the bean flowering, the variables associated with atmospheric nitrogen fixation were recorded: number of nodules (NN), dry weight of nodules (PSN), percentage of total nitrogen in the stem (NT) and chlorophyll content in the leaves (CL) in SPAD units. Multivariate analysis detected dif ferences for bean genotypes, Rhizobium strains, and for genotype × strain interaction. Cultivated bean genotypes generally outperformed wild bean genotypes in their response to the recorded variables. Similarly, isolates from cultivated beans were generally better than those from wild beans. The circular dendrogram separated the genotype-strain binomials first by gene pools of Andean and Mesoamerican beans, second by domesticated and wild bean forms, and third within each of the forms. The graph of the canonical analysis of principal coordinates showed a positive interaction of the cultivated bean-strains binomials with the four variables studied. The positive interactions of P Saltillo and Peruano 16 in NT and PSN in symbiosis with most of the strains stand out; of G Zarco in NN in symbiosis with six of the rhizobia; the interaction of Apetito in CL with six of the strains; the combinations of P Saltillo, Peruano 16 and G Zarco with the RhGz2 strain in the NT variable.
Modeling of Land use Change and Projection in Tenosique, Tabasco, Mexico
Tenosique, Tabasco is an important cross-border territory between Mexico and Guatemala due to the presence of tropical forests that provide an optimal space for the maintenance of biodiversity and the provision of environmental services. However, its current spatial dynamics are unknown, relevant information for the creation of environmental planning strategies in the Southeast of Mexico. For this reason, the objective of this work was to model land use change from 1997 to 2009 and 2016, using the Land Change Modeler. In addition, a 2030 scenario was constructed using stochastic transition models (Markov chains and cellular automata). The results show a loss of forests of more than 30 000 ha from 1997 to 2016 that were transformed into secondary vegetation, but mainly into pastures for cattle ranching. If this trend continues, it is expected that by 2030 the area of forests in the municipality will be reduced to 7% of the area. This work indicates that it is necessary to establish new conservation, restoration, and management strategies through an ecological management program of the municipality in coordination with the federal authorities that manage the Flora and Fauna Protection Area, Usumacinta Canyon.
Ef fect of Ulva lactuca and Gracilaria blodgettii Flours on the Physical and Chemical Properties of an Alkaline Soil and the Growth of Swiss Chard (Beta vulgaris var. cycla)
The use of seaweed as biofertilizers has positive ef fects on the growth and development of various crops as well as on soil improvement. The purpose was to evaluate its ef fect on some physicochemical properties of an alkaline soil and on the growth of Beta vulgaris var. cycla (Swiss chard). In this study, flours of Ulva lactuca and Gracilaria blodgettii were used in a Vertisol soil. Three treatments were evaluated: 3, 6, and 9 g kg-1 of soil in 5 kg pots, and a control without flour. The bioassay was conducted in a greenhouse, with each treatment having five replicates. Bromatological and metal analyses were performed on both flours. The soil was analysed for texture, cation exchange capacity (CEC), organic matter (OM), relative humidity (RH), electrical conductivity (EC), pH, water retention capacity (WRC), Na, K, P, and N. In the Swiss chard, weekly and total growth, fresh and dry biomass were measured. The results indicated that both species increased OM content in the soil, with G. blodgettii being more notable from 1.48-2.7%. In contrast, U. lactuca modified the pH, reducing soil alkalinity from 9.01 to 7.47, increased CEC from 48.28 meq 100 g-1 to 48.72 meq 100 g-1, WRC from 90 to 92.8%, exchangeable sodium capacity from 98 to 100 mg kg-1, and potassium from 125 to 142 mg kg-1. The addition of U. lactuca flour was beneficial to the soil, allowing the growth of Swiss chard with significant increases in total height (P = 0.02621) and dry biomass (P = 0.007867). It is inferred that the total ash concentration in U. lactuca is related to the mineral content and its biofertilizer ef fect; however, additional research is required to determine the optimal concentrations in alkaline soils.
The Ef fects of Polyethyleneimine Coating of Gold Nanoparticles on Photosynthesis and Growth of the Moss Physcomitrium patens
The widespread use of gold nanoparticles (Au-NP) as nanocarriers has led to several studies in animal cells to evaluate their cytotoxic ef fects. In contrast, little is known about the impact of gold nanoparticles on photosynthesis and plant growth. In this work, we present a study on the physiological and morphological responses of bryophytes to Au-NPs prepared with dif ferent contents of polyethyleneimine (PEI) using Physcomitrium patens (P. patens) as a model system. Results are presented where Au-NPs without PEI induce the generation of larger gametophores. On the other hand, Au-NPs with a high concentration of PEI were found to be phytotoxic. In contrast, Au/PEI-NPs with a medium PEI concentration cause early stress, but plant cells can recover growth, greening and photosynthetic activity under these conditions. Finally, low concentrations of Au/PEI-NPs do not cause adverse ef fects on P. patens in terms of growth, gametophyte development, and photosystem II maximum quantum yield. Toxicity was closely related to the content of PEI. This study reveals for the first time the ef fects of Au-NPs and Au/PEI-NPs on bryophytes at dif ferent growth stages.