Fosfato natural e resíduos da indústria de gelatina para adubação do capim BRS Zuri e capim Marandu

Abstract

The growing demand for food and national dependence on inputs provide opportunities for the use of regionalized solutions for fertilizing forage crops, to the detriment of chemical fertilizers. The general objective was to identify sustainable alternatives for fertilizing BRS Zuri and Marandu grasses. This thesis consists of four studies, and its objectives were (1) Evaluate the combinations of liming with phosphorus sources in BRS Zuri grass production; (2) Evaluate the chemical composition of the soil, leaf tissue, productivity, morphological and bromatological composition of Marandu grass and determine the dose of mixed gelatin sludge (LMG) for Marandu grass production in the rainy and dry periods; (3) Evaluate the productivity, morphological and bromatological composition of Marandu grass and determine the dose of biological gelatin sludge (LBG) during the rainy and dry periods; (4) Evaluate the chemical composition of the soil and leaf tissue of Marandu grass and determine the dose of LBG during the rainy and dry periods. Study 1 was in randomized blocks, arranged in a 3x2 factorial scheme, with three treatments applied in the presence of liming (Bayovar reactive natural phosphate - FN, monoammonium phosphate - MAP, without phosphate fertilizer) and three treatments associated with the absence of liming. Studies 2, 3 and 4 were in randomized blocks with six treatments: 0, 50, 100, 150 and 200% of the N requirement of Marandu grass, with LMG and LBG and mineral fertilizer (NPK). FN, LMG and LBG are recommended as sustainable alternatives for fertilizing tropical forage grasses, promoting increased productivity, improving the chemical characteristics of the soil and the bromatological composition of the forages. The combination of phosphates with limestone increases the productivity of green and dry matter, and plant height of BRS Zuri grass. LMG and LBG increase the productivity and quality of Marandu grass, and must be applied at doses of 200% of the N requirement, both during the rainy season and during the dry season.