Crescimento e trocas gasosas do feijão caupi cv. BRS pujante sob níveis de água disponível no solo e cobertura morta

Abstract

Cowpea is widely cultivated in arid and semiarid regions, where drought is a limiting factor to crop production, requiring the adoption of practices to improve the culture performance. In this context, the study was intended to assess the effect of levels of available water in the soil with and without mulch on the soil surface, in the growth and photosynthetic activity of Cowpea (Vigna unguiculata Walp.), cv. BRS Pujante bean. The study was conducted at the Centre for Science and Agrifood Technology of Federal University of Campina Grande, using a completely randomized design, with treatments arranged in a factorial scheme 5 × 2, corresponding to the levels of available water (AD) 20; 40; 60; 80 and 100%, maintained after soil irrigations, as function of mulch (CC) and without cover (SC) and four repetitions, totaling the 40 experimental units. After 45 days the cowpea plants were evaluated for growth and gas exchange. The highest growth in number of leaves and leaf area of BRS Pujante occurs in crops with water available in the soil above 75%. The soil cover reduced the effects of water stress on plant growth. The mechanism of tolerance of BRS Pujante plants is associated to the reduction of the number of leaves and leaf area and the increase of gas exchange in the remaining leaves. The cowpea cultivar BRS Pujante presents high levels of water use efficiency under conditions of low water availability.