Teor de nutrientes, propriedades físicas do solo e produtividade de soja após a aplicação de pó de rocha associado a plantas de cobertura

Abstract

The use of rock dust is an alternative to seek fertility balance, soil recovery and sustainable productivity. Thus, the objective of this research was to evaluate the effect of applying different doses of rock dust associated with cover crops, on the availability of nutrients, soybean yield and the physical properties of the soil. The experimental design used was randomized blocks in a split-plot scheme, with four replications. The main plots consisted of three crops: black oat, black oat + forage turnip intercrop, and no cover crop (no soil cover). The subplots were composed of five doses of rock dust: 0, 3, 6, 9 and 12 t ha-1. The following were evaluated: pH, H+Al, P, K, Ca and Mg in soil samples collected 6 and 12 months after the application of rock dust in the layers 0.00-0.05, 0.05-0.10 and 0.10-0.15 m; macroporosity, microporosity, total porosity and soil density in the layers 0.00-0.05, 0.05-0.10 and 0.10-0.15 m; and soybean yield. The results showed that the cultivation of the cover crops (black oat and black oat + forage turnip) increased the P and K contents by 29 and 92%, respectively, compared to the area without cultivation, which resulted in a 22% increase in soybean yields. Six months after the application of basalt rock dust there was an increase in the P content of the soil; and after 12 months when the rock dust was associated with cover crops there was an increase in the P and Ca content and a reduction in soil pH. The use of basalt rock dust at a dose of 8.4 t ha-1 resulted in a yield increase of 16%. Cultivation with cover crops did not promote improvements in soil porosity and density. The highest dose of basalt dust applied in this study (12 t ha-1) did not change soil porosity and density. The results demonstrate the potential of using rock dust as an input for sustainable agriculture.