Sistema Regional de Información
en línea para Revistas Científicas de América Latina,
el Caribe, España y Portugal

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.