Influence of the foliar spraying with NPK in ca and mg levels in cotton plants (Gossypium hirsutum L. raça Latifolium)

Abstract

This research was carried out in greenhouse of Escola Superior de Agricultura "Luiz de Queiroz", Piracicaba, São Paulo State, Brazil, in 1975/76; to study the influence of NPK spraying on leaves about composition of Ca and Mg in parts of cotton plant (Gossypium hirsutum L. raça Latifolium) Cv. IAC 13-1. The experimental design was a Randomized Complete Blocks with the treatments combined in a 2 x 3³ factorial with 3 replications. The treatments were: spraying-two (4 and 8) fertilizers-three (N, P, K) in three levels (0, 1, 2). This three levels had the following averages according to the numbers of spraying, sweh as: four spraying: N0 = 0; N1 = 0,44; N2 = 0,88; P0 = 0; P1 = 0,05; P2 = 0,10; K0 = 0; K1 = 0,33; K2 = 0,66; eight spraying: N0 = 0; N1 = 0,91; N2 = 1,82; P0 = 0; P1 = 0,10; P2 = 0,20; K0 = 0; K1 = 0,70, K2 = 1,40. The levels are expressed in kg/ha and the source of fertilizers used were: NH4NO3, NaH2PO4H2O and KCl for N, P2O5 and K2O respectively. The evaluation of the treatments were done based upon the percentage of Ca and Mg in dry matter of roots, stalls, young leaves and old leaves. The following conclusions could be drawn from this research: The N caused reduction of Ca and Mg levels in old and young leaves. The nutrients sprayings did not caused the Mg levels in the stalks. The plants with four spraying treatments had graster Ca levels in stalks and Mg levels in roots than with eight spraying treatments.