Efecto del vermicompost y estrés hídrico en frijol (Phaseolus Vulgaris L.): Parámetros productivos y relaciones hídricas

It is documented that vermicompost increases germination and productivity of crops, but little is known of its effect on plant physiological responses under soil water deficit. The aim of this study was to analyze the effect of vermicompost and irrigation interruption on stomatal conductance, gas exchange, and yield of common bean cultivars (drought tolerant -cv. 92 and drought susceptible-cv. 122). Plants were cultivated in unamended soil or soil amended with 1.5 and 3% of vermicompost, with irrigation during the whole cycle but irrigation interruption at the flowering stage. Changes in soil moisture, stomatal conductance (gs), transpiration (E), CO₂ assimilation (A), leaf temperature, water use efficiency (WUE) and yield components were measured. The wilting point in the soil was increased to 15%, in proportion to the vermicompost addition. It was observed that at 16 days without irrigation, gs and A were totally diminished, and E and WUE decreased (P≤0.05) 62 and 91%, respectively. Vermicompost reduced (P≤0.05) gs by more than 30%, while E dropped 16 and 49% with 1.5 and 3% vermicompost, respectively, in comparison to the treatments without vermicompost. Cultivar 122 had 23% lower (P≤0.05) WUE than cv. 92, although cv. 122 had higher yield, mainly with irrigation during the whole cycle. The number and biomass of seed increased more than 30% as an effect of vermicompost; this effect was observed in the two irrigation conditions. Vermicompost modified some physical and chemical soil properties, as well as gravimetric soil moisture content. At the same time, there was less stomatal conductance and a greater yield, mainly with irrigation.