Nitrogen and phosphorus use and their effects on irrigated cotton nutrition

Abstract

Water and nutrients management in cotton crop is very important to achieve high yields. Therefore, it is necessary to understand the fertilization effect on the nutritional status of cotton plants submitted to irrigated conditions. The objective of this study was to evaluate nitrogen and phosphorus fertilization on N, P, K, Ca, Mg and S leaf contents of in semiarid conditions. Treatments were arranged in a factorial scheme of four N doses (0, 90, 180 and 270 kg ha^-1) and four P doses (0, 120, 240 and 360 kg ha^-1) in a randomized block design with three replicates. P and 1/3 of N were applied at sowing and the remaining nitrogen at 38 days after emergence (DAE). At 80 DAE, the leaf contents of the macronutrients were determined. The application of 215 kg ha^-1 of N provided sufficiency for N and K leaf contents to achieve high yield and nutrition. In the semiarid regions, supplying sulfur (S) to soil, or using fertilizers containing it, is necessary in order to meet the S needs for cotton crop.