Avaliação de cinco calcários em diferentes granulometrias na cultura do sorgo

Abstract

Soil acidity in tropical and subtropical regions poses a challenge to agricultural productivity, especially due to the presence of toxic aluminum and deficiencies in calcium (Ca) and magnesium (Mg). Liming is a widely used practice to address this situation, correcting soil acidity, providing calcium and magnesium to plants, promoting root development, and thus favoring nutrient absorption. This study aimed to evaluate the effect of different types of limestone, with varying particle sizes, on sorghum (Sorghum bicolor (L.) Moench) grown in a greenhouse. The experiment was conducted at the Federal University of Uberlândia (UFU), in Uberlândia-MG, using a completely randomized design (CRD) in a 5x5 + 1 factorial scheme, with four replications. Five types of soil amendments with different CaO and MgO contents were evaluated (44.23% CaO and 7.68% MgO; 31.73% CaO and 20.26% MgO; 55.58% CaO and 1.84% MgO; 34.62% CaO and 23.79% MgO; 46.17% CaO and 13.44% MgO) and five particle size ranges (<0.297; 0.297-0.500; 0.500-0.840; 0.840-1.000 and 1.000-1.700 mm). The variables analyzed included shoot dry weight, calcium and magnesium content in the plant and soil, soil pH (in water and CaCl₂), potential acidity, and base saturation. The data were subjected to statistical analysis using Tukey's and Dunnett's tests at a 5% significance level, using RStudio software. The results demonstrated that the corrective with 44.23% CaO and 7.68% MgO provided the highest levels of foliar calcium, while the limestone with 31.73% CaO and 20.26% MgO resulted in the highest levels of magnesium in the soil in particle diameters <0.297 mm and 1.000-1.700 mm, in addition to foliar magnesium, which obtained superior results in particles smaller than 1.0 mm. Thus, it is concluded that both the type of limestone and its particle size significantly influence the nutrient dynamics in the soil and the development of the sorghum crop.