AVALIAÇÃO DE MÉTODOS DE NECESSIDADE DE CALAGEM NO BRASIL

Abstract

Considering soil acidity importance under tropical conditions and the existence of several limingrequirement evaluation methods, this work aimed to evaluate liming requirement methods in use in Brazil. Experimental units were plastic cups with 0, 1, 2, 3 and 4 t ha-1 of CaCO3, in a factorial arrangement with three soil classes, under a block design with five replicates. pH readings were obtained each seven days for eight weeks. Regression analysis and model selection was done for pH, Al3+ and Ca2++Mg2+, considering CaCO3 levels as independent variables, for each soil. Obtained equations were used to estimate pH, Al3+ and Ca2++Mg2+ which would be obtained if liming was conducted according to the liming requirement methods. Data estimated for each soil was submitted to analysis of variance, with each soil being a replicate. Base saturation, exchangeable aluminum neutralization, or exchangeable calcium and magnesium content increase had the best results for pH. These methods achieved liming goals, while the remaining resulted in pH below desirable.