Effects of biotite syenite on the nutrient levels and electrical charges in a Brazilian savanna ferralsol1

Abstract

In the Brazilian Savanna, most of the soils have a low natural fertility. In order to overcome this limitation, farmers use large amounts of soluble fertilizers, causing environmental impacts. In the present study, finely ground biotite syenite (0; 600; 1,200; 1,800; and 2,400 kg ha-1) was evaluated as an alternative source of nutrients and electrical charges in a weathered Ferralsol from the Brazilian Savanna. Additionally, the development and nutrition of maize plants were analyzed. The values of Ca + Mg, T, t, Zn, Cu, Fe and Mn in the soil were not affected by the addition of biotite syenite, but the available P and K and the permanent charges were increased. The biotite did not increase the contents of P, Ca and Cu in the maize leaves, but it increased the contents of N and K. Increases of 103, 125 and 128% were also detected, respectively, for plant height, stem diameter and leaf dry matter. The biotite syenite was able to increase the soil P, K and permanent charges, as well as the maize uptake of N and K, thus helping in the plant growth.