AVALIAÇÃO DO ESTADO NUTRICIONAL DO COQUEIRO ANÃO VERDE FERTIRRIGADO COM NITROGÊNIO E POTÁSSIO

Abstract

A field experiment was developed in the period of April of 2000 to May of 2002, at the Experimental Station of Jiqui pertaining to the Empresa de Pesquisa Agropecuária do Rio Grande do Norte - EMPARN, Parnamirim city, state of Rio Grande do Norte. The work had as objective to evaluate the effects of nitrogen and potassium applied through irrigation water on the nutritional state of green dwarf coconut tree (Cocos nucifera L). The treatments had consisted of the combination through the experimental matrix of Plan Puebla III, 5 doses of N and 5 doses of K2O both oscillating of 135 the 2565 g plant -1 year -1 derived of the urea and white potassium chloride. The used experimental A field experiment was developed in the period of April of 2000 to May of 2002, at the Experimental Station of Jiqui pertaining to the Empresa de Pesquisa Agropecuária do Rio Grande do Norte - EMPARN, Parnamirim city, state of Rio Grande do Norte. The work had as objective to evaluate the effects of nitrogen and potassium applied through irrigation water on the nutritional state of green dwarf coconut tree (Cocos nucifera L). The treatments had consisted of the combination through the experimental matrix of Plan Puebla III, 5 doses of N and 5 doses of K2O both oscillating of 135 the 2565 g plant -1 year -1 derived of the urea and white potassium chloride. The used experimental delineation was of blocks at random with 4 repetitions and 5 plants for plots totalizing 40 experimental units. The plantation was made in the triangular spacing of 7.5 m between plants and 7.5 m between lines. When the plants were with 4, 4.5 and 5 years had been made three foliar material collections in two plants for parcel in 9 and 14 number leaves. With the results of the analyses proceeding from these collections they had extracted to the averages and was made the statistics analysis. In the samples, they were determined the N, K, P, Ca, Mg and Cl concentrations. Only the N presented concentration below of the critical level, the other P, K, Ca, Mg and Cl nutrients had presented its concentrations above of this level. There was not trend defined between 9 and 14 levels in relation to the N, P, K, Ca, Mg and Cl concentration. The N concentrations had increased proportionally and linearly and to the amount of N applied. The K concentrations had increased proportionally of quadratic form to the amount of applied N. The K concentrations had increased of quadratic form proportionally to the K doses and linearly to the N doses. There was no effect of the N and K doses on the Ca proportions, the Mg concentrations of Mg had diminished linearly with the rise of the N and K doses. The Cl concentrations had increased with the rise in the N and K doses. Considering the evaluated nutrients and the shown leaves, it is possible affirm that the plants were nutritiously were balanced.