Abstract:Rice paddies contribute significantly to agricultural greenhouse gas emissions through continuous flooding practices. This multi-site study evaluated alternate wetting and drying (AWD) irrigation effects on rice productivity and methane emissions across tropical Asian and Latin American production systems. AWD treatments reduced irrigation water use by 23-35% and methane emissions by 45-65% compared to continuous flooding. Yield impacts ranged from negligible to 8% reductions depending on soil type and water table depth. Nitrous oxide emissions showed variable responses requiring careful nitrogen management under AWD. Life cycle assessment confirmed net climate benefits of 35-50% reduction in global warming potential per kilogram rice produced. Guidelines for AWD implementation across diverse agroecological conditions support climate-smart rice intensification.
Abstract:Urban aquaponics offers potential for local food production in densely populated Latin American cities. This research assessed the technical performance and economic viability of small-scale aquaponics systems operated by urban households and community organizations. Twelve pilot installations were monitored for fish and vegetable productivity, water quality parameters, and operational costs over 18 months. Systems produced average yields of 25 kg fish and 180 kg vegetables annually per 10 m² installation. Economic analysis indicated breakeven within 14-20 months when valuing labor at opportunity cost rates. Social benefits including food access, nutrition education, and community building complemented economic returns. Design recommendations and training curricula were developed for scaling urban aquaponics programs.
Abstract:Soil microbial communities drive essential ecosystem functions in agricultural systems. This comparative study analyzed soil microbiome composition and functional potential under organic and conventional vegetable production over an eight-year period. High-throughput 16S rRNA and ITS sequencing revealed 35% greater bacterial diversity and 28% higher fungal richness in organic systems. Functional profiling indicated enhanced nutrient cycling, disease suppression, and plant growth promotion capabilities in organic soils. Network analysis demonstrated more complex and stable microbial interaction patterns under organic management. Transition dynamics showed progressive microbiome recovery following conversion from conventional practices, with functional indicators responding faster than taxonomic diversity measures.
Abstract:Shade-grown coffee systems provide multiple ecosystem services while potentially enhancing beverage quality. This research quantified relationships between shade tree composition, microclimate modification, and coffee cup quality across 24 farms in Costa Rican highlands. Agroforestry plots maintained temperatures 2-4°C lower than full-sun plantations during hot periods, with corresponding reductions in vapor pressure deficit. Coffee beans from diverse shade systems exhibited 12-18% higher sucrose content and superior sensory scores for acidity and body attributes. Shade tree species composition influenced bean biochemistry, with Inga spp. and native timber species producing optimal quality outcomes. Economic analysis confirmed premium prices for shade-grown certified coffees offset modest yield reductions.
Abstract:Native bean landraces represent valuable genetic resources for food security and crop improvement. This study documented genetic diversity and farmer management practices for Phaseolus vulgaris landraces across 28 highland communities in Guatemala and Honduras. Molecular marker analysis identified 156 distinct genotypes clustered into 12 genetic groups. Farmer surveys revealed selection criteria prioritizing cooking quality, taste, and storage characteristics alongside agronomic traits. Participatory variety trials demonstrated superior performance of local landraces under low-input conditions compared to improved cultivars. Community seed banks were established combining ex-situ conservation with in-situ farmer management to maintain adaptive genetic diversity while supporting food sovereignty objectives.
Abstract:Water scarcity limits rainfed maize production in semi-arid regions of Mexico. This research evaluated traditional and improved water harvesting techniques including contour ridging, tied ridges, and micro-catchments over four growing seasons. Soil moisture monitoring revealed 25-40% higher water retention in harvesting treatments during critical growth stages. Maize grain yields increased by 35-58% compared to conventional flat planting, with tied ridges showing optimal performance in years with irregular rainfall distribution. Root development patterns indicated deeper soil water extraction in water-harvested plots. These low-cost techniques offer practical solutions for smallholder farmers adapting to increasing rainfall variability under climate change.
Abstract:Native Trichoderma strains were isolated and evaluated for biocontrol efficacy against major fungal pathogens affecting greenhouse tomato production. Forty-two isolates from Colombian agricultural soils were screened for antagonistic activity against Fusarium oxysporum, Botrytis cinerea, and Alternaria solani. Selected strains demonstrated in vitro inhibition rates of 65-82% through mycoparasitism and antibiosis mechanisms. Greenhouse trials showed disease severity reductions of 55-70% compared to untreated controls, with yields comparable to fungicide-treated plots. Formulation development using agricultural byproducts produced stable biocontrol products maintaining viability for six months. Native Trichoderma strains offer effective, environmentally sustainable alternatives for integrated disease management.
Abstract:This study evaluates the adoption and effectiveness of precision agriculture technologies across diverse farming systems in Latin America. Research was conducted on 45 farms implementing variable rate fertilization, drone-based crop monitoring, and GPS-guided machinery. Results demonstrated fertilizer use reductions of 18-25% while maintaining or improving yields. Remote sensing indices accurately predicted crop nitrogen status with R² values exceeding 0.85. Economic analysis revealed positive returns for medium to large-scale operations, though smallholder adoption barriers persist. Policy recommendations address infrastructure investment and cooperative models to extend precision agriculture benefits across all farm scales in the region.
Abstract:Drought stress is one of the most limiting factors, mainly in Mediterranean and arid or semi-arid environments worldwide. This situation is not an exception in central Chile, where a decline in rainfall of approximately 25% to 45% has been recorded over the past few decades, affecting mostly family farm agriculture. The main objective of the present study was to assess the intercropping of legume and cucurbits with maize, as a starting point to determine the best combinations. The experiment was conducted under greenhouse conditions in a bifactorial arrangement based on a completely randomized design with three replications. The treatments included 13 cropping systems: (T1-maize, T2-common bean, T3-chickpea, T4-pumpkin and T5-cucumber, as sole crops; T6-maize and common bean, T7-maize and chickpea, T8-maize and pumpkin, T9-maize and cucumber, T10-maize, common bean and pumpkin, T11-maize, common bean and cucumber, T12-maize, chickpea and pumpkin, and T13-maize, chickpea and cucumber); and two irrigation levels (40% and 100% of water holding capacity (WHC) of substrate, named as R100 and R40, respectively). The results showed that intercropping system and irrigation level altered morphological and physiological parameters. The water deprivation decreased significantly root and shoot biomass, height and relative growth rate of all the crops. Moreover, the results showed that intercropping enhanced land use productivity, with a land equivalent ratio (LER) with a median of 1.30. Overall, the results of the current study indicated that intercropping of maize, common beans and pumpkin could aid smallholder farmers to cope with water shortage, particularly in Mediterranean and other arid and semi-arid environments.
Abstract:This study focuses on the in-depth assessment of the spatio-temporal variability of rainfall in the Upper Medjerda Valley and its direct impact on the hydrological response of the watershed. To this end, a rainfall database spanning from the hydrological year 1980/1981 to 2014/2015 was compiled, gathering the average time series of 16 rain gauges strategically distributed across the studied basin. Missing data, inherent in any long-term collection, were systematically reconstructed using a weighting method, thus ensuring the integrity and continuity of the series. Subsequently, a rigorous statistical analysis was conducted to detect significant breaks in each individual rainfall time series. Three statistically robust tests – Pettitt, SNHT (Standard Normal Homogeneity Test) and Buishand – were applied using XLstat software. These tests, combined with the detailed calculation of specific rainfall indices, highlighted a pronounced alternation of wet and dry episodes, characterized by occurrences of very high rainfall excesses, thus highlighting the complex dynamics of the region's rainfall regime. The next step consisted of a spatial interpolation of rainfall, carried out at different time scales: annual, monthly and seasonal. Three geostatistical and deterministic interpolation methods were used to ensure robustness of the results: the Theissen polygon, splines and ordinary kriging. The average rainfall maps thus generated for the Upper Medjerda Valley then served as an essential basis for the hydrological study. Finally, the study focused on examining the variation of hydrological contributions, establishing their quantitative relationship with rainfall, and assessing their crucial importance for the basin. This was achieved through the implementation of the conceptual hydrological model GR2m. It has been shown that runoff, and by extension, available water resources, constitute the direct and fundamental hydrological response of the watershed to rainfall events, highlighting the close interdependence between precipitation patterns and water availability.