Agronomic feasibility of using basalt powder as soil nutrient remineralizer

Tropical agriculture is highly dependent of soluble fertilizers, what raises the cost of production. An alternative to reduce the costs inputs is the use of low-cost alternative nutrient sources, such as the basic rocks. The aim of the work was to evaluate the effect of basalt powder on the soil chemical properties and plant growth. The experiment was arranged in a 2×2×2×3+4 factorial scheme: two soils (clay soil and sandy clay loam soil); two crops (maize and soybean); two agricultural inputs (basalt rock powder and limestone); three application rates (33, 66 and 99 Mg ha–1 of basalt powder or 1, 2 and 4 Mg ha–1 of limestone), and four additional control treatments, with four repetitions. The use of basalt powder resulted in greater shoots growth of maize and soybean plants when compared to the limestone. Basalt powder provided a significant increase in soil pH, Ca and P concentration; however, the higher concentration of P in the soil did not result in the greater P uptake by the plants. Even without a significant increase in the Mg concentration of the soil, basalt rock powder improved the absorption of this nutrient by the maize and soybean plants. Key words: Remineralizer, rock, soybean, maize.