Estudo comparativo das relações entre os nutrientes dosados em folhas de café, citros e milho

Abstract

O processo de regressão e correlação simples e múltipla, medindo o grau de relação entre as variáveis, é de grande aplicação no estudo dos problemas de nutrição mineral. 1 2 Os teores dos nutrientes dosados na folha através de análise química foliar não revelam por si só o estado nutricional adequado de uma planta, sendo também de importância a relação de equilíbrio em que se encontram. Com base nos teores dos nutrientes determinados nas folhas de milho, citros e café, procurou-se estabelecer, através de um estudo de regressão e correlação múltipla, os diferentes tipos de relação entre os nutrientes nessas culturas.

From the analysis of leaves of coffee, citrus, and corn plants, comparative studies were made in order to establish relations among several elements. The leaf samples for the chemical analysis were collected from plants grown on four types of soils, as described below. 1 — Latosolic B 2 — Ortho-Red Yellow Podzolic soils 3 — Podzolized Soils on calcareous sandstone of Lins and Marília variation 4 — Ortho Dark Red Latosol Multiple correlation as well as multiple regression were determined, and the relations among the elements are described. The results confirmed relations already known through simple correlations as the antagonism between K and Ca and/or K anda M g , the latter being strong in Latosolic B. Moreover, they revealed the existence of other ones. + 2+ + 2+ Calcium and phosphorus showed antagonism in corn and coffee and syner- gism in citrus leaves. On the other hand, while sinergism ocurred between N and P in corn and coffee, there was an antagonism in citrus between these elements. Phosphorus correlated positively with K in the three crops studied. + No or few significant correlation coefficients were found for the micronu¬ trients.