Comparison between Limestone and Silicate Corrective Associated Gypsum in the Growth of a Forage Grass

Abstract

ABSTRACT Soil acidity is one of the most limiting factors in crop yield. We evaluated the effect of soil acidity correction with magnesium limestone and calcium (Ca) and magnesium (Mg) silicate associated gypsum application, on the growth of a forage grass. The experiment was conducted in a greenhouse with a soil sample from B horizon of a Rhodic Hapludox. The experimental, design was completely randomized blocks with seven treatments each replicated four times. Two sources of amendments (magnesium limestone and calcium and magnesium silicate) were incorporated in a surface (0 to 0.20 m) soil sample using three application methods: amendment without gypsum, amendment with gypsum incorporated in the sample, amendment with superficial application of gypsum, and a control treatment without amendment and gypsum. The limestone and silicate were effective in correcting acidity and increasing exchangeable soil bases in the 0.20 m layer. The use of acidity correctors combined with gypsum, mainly incorporated, neutralized toxic aluminum and increased the levels of sulfate and Ca in depth and the concentrations of Ca, Mg, nitrogen and phosphorus in dry weight of the shoot (DWS). The silicate increased the concentrations of silicon (Si) the soil up to 0.20 m depth and Si concentration in the plant. The silicate with gypsum provided greater production of DWS, while limestone with gypsum increased the production of dry weight of roots the plant. The application of silicate in complement to limestone, combined with incorporated gypsum is the most suitable method for soil correction in the implantation of mombaça grass.