Fontes orgânicas na composição de fertilizantes organominerais peletizados para a cultura do sorgo

Abstract

Organo-mineral fertilizers are an opportunity for technological innovation, since they allow the correct use of waste from several agroindustrial sectors, which is a global problem, to add value to the by-product generated, as prioritized in reverse logistics. In this sense, the objective of this work was to evaluate the effect of organic matter sources on the composition of organo-mineral fertilizers pelleted in relation to the exclusive use of mineral fertilizers in the cultivation of sorghum, and to verify the benefits of this fertilizer in the performance of the crop for the production of biofuel. The experiment was conducted at the Experimental Farm of the Federal Institute of the Triângulo Mineiro, located in the city of Campina Verde, State of Minas Gerais, Brazil. The experimental design was a randomized block design with four replicates in the factorial scheme 3 x 2 + 2, corresponding to three levels of fertilization with pelleted organo-mineral fertilizer (70, 100 and 160% based on the recommended dose of phosphorus) and two sources of organic matter in the composition of organo-mineral fertilizers (sewage sludge and filter cake), as well as two additional treatments (without fertilization and exclusively mineral fertilization). The evaluations were: plant height, leaf number and stem diameter at 30, 60 and 90 days after sowing (DAS); total plant height; dry mass of aerial part per plant and per hectare at 90 DAS; in vitro digestibility of organic matter at 90 DAS; the relationship of leaf area per leaf and leaf area per plant at 90 DAS. The plant height variables at 30, 60 and 90 DAS and total plant height had a significant effect between levels of organo-mineral fertilizers and among the additional treatments. Only height at 90 DAS and total plant height had a significant effect among organic sources. There was interaction between levels of fertilization with organo-mineral fertilizers and organic sources for plant height at 60 and 90 DAS, and for the total height of plants. Plant height at 30, 60 and 90 DAS, total plant height and in vitro digestibility showed quadratic effect for filter cake and sewage sludge. Sewage sludge and filter cake, used as an organic source for organo-mineral fertilizer production can be a great economic and environmental strategy for farmers and agribusiness, and for substitution to exclusively mineral fertilization.