Food legumes are widely grown as a source of protein in semiarid and tropical regions, but production is often limited by the large variation in the amount and distribution of rainfall. Mungbean (Vigna radiata L.), cowpea (Vigna unguiculata L.), soybean (Glycine max L.), and peanut (Arachis hypogeae L.), often planted after rice (Oryza sativa L.), were compared for response to a season‐long moisture stress on medium‐deep Tropudalf soil, using a line‐source sprinkler irrigation system during the January to April 1982 dry season. Drought stress reduced seed yield of all four food legumes, but the reduction due to water stress was greater in mungbean followed by soybean, cowpea, and peanut. Mungbean produced significantly lower yields at all moisture levels than the other legumes. Total water use by peanut was highest, followed by cowpea, soybean, and mungbean. Among yield components, the numbr of pods per square meter was most affected by water stress in all four species, followed by number of seeds per pod, while seed weight was least affected. Harvest index decreased Linearly with increasing levels of drought for all four species.

Plant growth in semiarid and tropical regions is often limited by variations in the amount and duration of rainfall. Four food legumes, mungbean (Vigna radiata L.), cowpea (Vigna unguiculata L.), soybean (Glycine max L.), and peanut (Arachis hypogeae L.) were subjected to different moisture gradients in the field on a medium‐deep Tropudalf soil. Water stress effects on the shoot and root growth were analyzed to determine relationships with seed yield and plant growth and to evaluate possible drought avoidance mechanisms. Water stress was created with a line‐source sprinkler irrigation system. Plant growth analyses were computed from samples taken at frequent intervals during the vegetative and reproductive phases. Increasing moisture stress resulted in progressively less leaf area, leaf area duration (LAD), crop growth rate (CGR), and shoot dry matter. Conversely, specific leaf weight increased with increasing levels of water stress. The four seed legumes differed in their ability to maintain leaf area expansion rate, leaf area index, LAD, CGR, and shoot dry matter at high levels of water stress. Cowpea and peanut had higher root densities at 0.4 to 0.8 m soil depths than soybean or mungbean and this appeared to be a major adaptive mechanism for their drought tolerance.

Environmental conditions affect biocontrol agents in a field, being appropriate formulations an alternative to overcome this problem. Formulations based on Trichoderma asperellum TV190 were prepared by emulsified mineral or vegetable oils, which protected spores from ultraviolet radiation, showing greater viability of 37-43% (mineral) and 56-63% (vegetable) than the control (8-12%). These formulations improved an antagonism of T. asperellum on Rhizoctonia solani under greenhouse conditions, reducing infected corn seedlings by 72% (mineral) and 59% (vegetable). Necrotic spot size was reduced by 90.04% (mineral) and 87.29% (vegetable). A granular formulation, prepared with degreased corn germ and T. asperellum spores, protected the corn seedlings from R. solani under greenhouse conditions, with 73% reduction of infected plants and 93% reduction of necrotic spot size. Both granular and liquid formulations were able to improve T. asperellum antagonism, suggesting that these formulations could be included in agricultural pest control strategies.

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