Respostas do feijão-caupi à diferentes lâminas de irrigação com água salina e doses de biofertilizante

Abstract

The objective of this study was to evaluate the responses of cowpea (Vigna Unguicullata L. Walp) produced under the effect of different irrigation with saline water and liquid biofertilizer doses. Held this experiment in an experimental area Federal Institute of Ceará, located in the municipality of Umirim - CE with the cultivar of cowpea “BRS Pujante”. The experiment obeyed in a randomized block, in a split plot, totaling sixteen treatments and four repetitions. The plot consisted application of four different irrigation water with saline water (75; 100; 125 and 150% of crop evapotranspiration - ETc) and the subplots consisted of four different biofertilizer doses (0; 60; 120 e 180ml/plant). To perform irrigation was using a system drip. The water utility is classified as C4S1 and has electrical conductivity 3.81 dS.m-1. The biofertilizer was prepared in aerobic system, using water and cattle manure in the proportions of 1:1. The doses used were divided in three applications, this being performed at 10, 40 and 70 days after sowing – DAS. To 15, 45 and 75 DAS, they were analyzed chlorophyll content A e B and gas exchange in plants of cowpea, and the end of the experiment the growth, productive components and grain yield per plant. The results were subjected to the analysis of variance by F and their means compared by test Tukey and regression analysis. The results showed significant interaction between factors, getting meaningful answers to 75 DAS for the chlorophyll A. For gas exchange dose 120ml / bio-fertilizer plant was the best interacted with the laminae to 15 and 45 DAS. To 75 DAS the water depth was significant, adjusting the linear model for photosynthesis and stomatal conductance and quadratic for the concentration internal CO2 and transpiration. For growth , the increase in water depth provided to increase dry matter and total leaf área, being observed respectively adding up 32,42 and 64%. The increase of biofertilizer dose provided increment the number of sheets , fitting the quadratic model and reaching peak on the dose of 80 ml/plant. The production of dry grains , the interaction between the factors was significant , with higher averages in the blades of 100% of ETc and reaching a production of 23.76 and 23.07 g under the doses of 0 and 60 ml/plant of biofertilizers, respectively. Thus the application of different irrigation responded significantly culture , observed higher values when applied blades above 100 % of the ETc. For biofertilizers its application did not respond significantly the variables analyzed.