Soil acidity correction on a Red-Yellow Distrophic Latosol from the west of Parana state (Brazil)

Abstract

Quantities of lime to be applied on a Red-Yellow Distrophic Latosol, from Western Paraná to either correct the exchangeable acidity or raise the original pH to 6,5 were determined by incubations. This study allowed also to show the effects of the different soil acidity levels on the amount of chemically extracted AI³ , Ca²⁺ + Mg²⁺, P and K⁺ on the soil. The rate of 2,0 ton/ha of lime for each eq. mg of AI³⁺ was adequate to neutralise the exchangeable acidity and to increase the soil pH to 5,4 while 12,0 t/ha were required to increase the soil pH to 5,5. In cases in which soil pH was greater than 5,4 the exchangeable AI³⁺ was equal to 0, and Ca² + Mg² content greater than 4,7 eq., g/100 ml of soiL. Liming, at any soil acidity level studied, did not influence the weak acid extractable soil P, but there was a slight decrease on the amount of exchangeable K.