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Periódicos Brasileiros em Medicina Veterinária e Zootecnia

p. 2493-2506

Changes in soil chemical reactions in response to straw sugar cane and vinasse

Silva de Aquino, Giselede Conti Medina, CristianeRodrigues Brito, OsmarCristina de Batista Fonseca, Inês

Sugarcane harvesting is predominantly mechanical because of environmental restrictions, reduced requirements for manpower, and the quest for improved efficiency. Therefore, large amounts of straw remain available in the soil. Vinasse, a liquid waste, is a main byproduct of the sugar and alcohol industry, in addition to sugarcane straw. Both accumulate in sugarcane fields; however, the effects of their interaction are unclear. In this study, the effects of applications of sugarcane straw and vinasse on the pH and the potassium (K), calcium (Ca), and magnesium (Mg) concentrations of a dystroferric Red Nitosol with a high base saturation were examined. The profiles of soil samples from sugarcane plantations collected at depths of 0-0.05, 0.06-0.10, 0.11-0.20, and 0.21-0.30 m were reproduced in 64 polyvinyl chloride (PVC) columns with dimensions of 0.036 × 0.30 m (diameter × height). The soils were treated with doses of 0, 125, 250, and 500 m3 ha-1 sugarcane vinasse and 0, 3, 6, and 9 t ha-1 sugarcane straw and incubated for 60 days. Following the analysis, by layer, the data were subjected to analysis of variance by partitioning the degrees of freedom into orthogonal polynomials. The pH and the Ca, Mg, and K concentrations increased throughout the soil profile upon vinasse application. An acid-base imbalance was observed in the topsoil layers in association with the high K saturat

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