Disponibilidade de K e P a partir de pó de Kamafugito em solos de diferentes classes texturais

Abstract

The feasibility of alternative sources of nutrients such as potassium (K) and phosphorus (P) are important for agricultural crops in Brazil. In this sense, the use of rock powders as a source of nutrients can be an alternative to national agricultural production. The objective of this work was to evaluate the release of K and P from kamafugite powder in soils of contrasting textural classes present in the Brazilian cerrado (Latossolo Vermelho Clay textured acric and Sandy textured Quartzite Neosol). In the experiment, four doses of K-K2O were tested from kamafugite powder, which was previously milled with granulometry smaller than 0.3 mm. The following doses were considered: K-K2O from rock dust: 0, 5, 10 and 15 g/dm3. The experimental unit was constituted per 100 g of air-dried fine earth, treatments being arranged in a factorial scheme 2x4x2 which were distributed in experimental design entirely randomized, with four replications. After 60 and 120 days of rock dust incubation, the soils were subjected to the extraction of exchangeable levels of K (ammonium acetate) and, available from P (Mehlich 1). The rock dust was evaluated by chemical mapping of surface and mineralogical composition. The contents of K, P, Ca, Mg, Al (exchangeable), acidity active and potential were submitted to analysis of variance and test of means in the software R. Regarding the availability of nutrients, the kamafugite powder was released for the variables K, Ca, Mg, P, H+Al and active acidity, with Al neutralization. both soils in their respective incubation periods showed significant interaction for the K – Mehlich 1 and ammonium acetate extraction methods, with the highest levels being found for the first extractor. The use of kamafugite as a source of nutrients seems to be unfeasible, due to the little release in relation to the ton of product applied.