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

Abstract

In order to study the effect of leveis of available water in the soir with and without mulch on the soir surface under the growth and photosynthetic activity of bean Cowpea (Vigna unguiculata Walp.), cv. BRS Pujante. The study was conducted at the Centre for Science and Technology Agrifood the Federal University of Campina Grande, using a completely randomized design, with treatments arranged in a factorial scheme 5 x 2, corresponding to the leveis of available water (AD) 201 401 601 80 and 100%, maintained after the soil irrigation, depending on the mulch (CC) without cover (SC) and four repetitions, totaling the 40 experimental units. At 45 days the cowpea plants were evaluated for growth and gas exchange. The highest growth in number of leaves and leaf área of BRS Pujante occurs in water with crops available in the soil above 75%. The soil cover reduced the effects of water stress on plant growth. The mechanism of tolerance of plants of the BRS Pujante is related to reducing the number of leaves and leaf área and the increase of gas exchange in the remainlng leaves. The cowpea cultivar BRS Pujante presents high leveis of efficiency of water use under conditions of low water availability.