Uso de águas salobras na produção de amendoim irrigado por pulsos

Abstract

The use of pulse irrigation with brackish water can provide higher yields for the peanut crop compared to continuous irrigation with brackish water, promoting greater accumulation of nutrients and greater crop production. Studies that relate this technique to salinity are scarce, especially with regard to mineral nutrition. The objective of this study was to evaluate the effect of the use of brackish water and pulsed and continuous drip irrigation on the production and accumulation of nutrients in the peanut culture. The research was carried out between September and November 2019 in the experimental area of the Agricultural Engineering Department of the Federal Rural University of Pernambuco, Recife-PE, Brazil, in open field lysimeters. The experimental design used was completely randomized blocks, in a 6 x 2 factorial scheme, the first being composed of six electrical conductivities of irrigation water (0.2; 1.6; 2.8; 4.0; 5 , 2 and 6.4 dS m-1) and the second factor for two forms of irrigation application (with pulses and continuous), with four repetitions. The harvest was carried out at 63 days after sowing (DAS). With the exception of the percentage of hatched pods and percentage of perfect grains, salinity negatively influenced all the production variables studied (fresh and dry mass of the aerial part, 10 grains, pods, grains, production, in addition to the number of pods and the number of grains). The lowest percentages of hatching pods were obtained with pulsed irrigation. Fruit and peanut grain production were the variables most affected by salinity. With regard to nutrients, the salinity of the water provided decreases in the accumulations of all studied nutrients (N, P, K, Ca, Mg, S, Fe, Mn, Cu and Zn) and increases in the accumulations of the elements chloride and sodium. Pulse irrigation provited greater production and greater accumulation of nutrients in the peanut crop compared to continuous irrigation. The decreasing order in the accumulation of nutrients by the pulse irrigated peanut culture was: K> N> Ca> Mg> P> S> Mn> Fe> Zn> Cu, and for continuous management it was: K> N> Ca> Mg> P> Mn> S> Fe> Zn> Cu.