Relações entre doses de calcário e manganês na nutrição mineral da soja na região de Rio Verde-Go

Abstract

This study aimed to assess the effects of liming and manganese rates on mineral nutrition of soybean on two representative soils from Rio Verde-GO, Brazil. A greenhouse experiment was undertaken at the School of Agronomy (Federal University of Goiás, Brazil), using an Oxisol (Latossolo Vermelho Amarelo Distrófico fase Cerrado) and an Ultipsamment (Neossolo Quartzarênico Distrófico fase Cerrado). A completely randomized experimental design was used, in a 5x5 factorial treatment design (liming and manganese rates), with three replications. The studied soils showed serious nutritional shortcomings, due to their high acidity levels and excess of exchangeable manganese. Treatments without liming provoked widespread Ca and Mg deficiencies and manganese toxicity, with visual symptoms in soybean leaves. Close relations among Ca, Mg, and Mn accumulated in soybean leaves as functions of applied liming and manganese rates have been found. One may conclude that liming is essential both as a soil acidity neutralizer, as a nutritional source of Ca and, as well to prevent accumulation of manganese in plants at toxic levels. Application of Mn on both studied soils is unnecessary for the soybean crop.