Alterações químicas de um latossolo vermelho aluminoférrico típico submetido à calagem e gessagem

Abstract

The fertility of tropical soils, particularly the Red Alumino-ferric Latosols found in Southern Brazil, is intrinsically dependent on the interactions between soil acidity, nutrient availability, and soil amendments. Consequently, elucidating the effects of liming and gypsum application on these factors is crucial for establishing a chemical environment conducive to root development and essential nutrient uptake. This study aimed to evaluate the effects of limestone and agricultural gypsum, applied both individually and in combination, on the chemical properties of a Red Alumino-ferric Latosol. It was hypothesized that limestone acts predominantly in the surface layers by increasing pH and phosphorus availability, whereas gypsum facilitates the vertical translocation of calcium, magnesium, and sulfur, while also indirectly affecting potassium dynamics. Results indicated higher pH and SMP index values in the 0-10 cm layer, consistent with the low mobility of limestone. Phosphorus exhibited marked surface stratification due to intense fixation by iron and aluminum oxides. Incorporated liming elevated P concentrations, aligning with the known effects of pH on nutrient desorption. Conversely, sulfur levels increased significantly in gypsum-treated plots, reflecting the high mobility of sulfate and confirming the amendment's efficacy in supplying Ca and S to the subsoil. In conclusion, liming and gypsum application function complementarily: liming neutralizes acidity and enhances phosphorus availability in the topsoil, while gypsum ameliorates subsoil fertility by supplying calcium and sulfur and influencing cation movement. Therefore, the combined use of these practices represents an efficient strategy for optimizing soil chemical conditions and fostering a balanced environment for plant growth.