Disponibilidade e lixiviação de nitrogênio em dois solos típicos de Pontes e Lacerda, MT, tratados com resíduo ruminal bovino

Abstract

High production of waste during the slaughter of cattle increases the need to promote their correct utilization. In this study, the availability and leaching of nitrogen (NO3- and NO4+) after bovine rumen residue (BRR) incorporation was evaluated in 2 typical soils of Pontes e Lacerda, MT: a distrophic Red Latosol and a eutrophic Yellow-Red Argisol. The experiment was conducted in a greenhouse at the University of State of Mato Grosso, UNEMAT, between December 2009 and March 2010. The samples were undisturbed soil in PVC tubes (length 40 cm; diameter, 10 cm), in which doses of BRR were added to provide 0, 50, 100, and 400 kg N ha-1 and urea was added to provide 400 kg N ha-1. Each treatment was performed using 4 replicates. The columns were irrigated weekly, and the leachate was collected and stored for analysis. After the experiment, soil samples were collected from 10 to 10 cm and the NO3- and NO4+ concentrations were determined. The use of BRR resulted in higher potential availability of N in distrophic Red Latosol, while in the eutrophic Yellow-Red Argisol, BRR could not supply adequate amount of nitrogen to the soil within the study period. In terms of N leaching, the distrophic Red Latosol has higher retention capacity for NO3- and lower retention capacity for NO4+ than eutrophic Yellow-Red Argisol; however, the levels of NO3- and NO4+ in the leachate collected from the 2 soils were within the standard values established by Resolution Conama 357/2005. The use of BRR as compared to the use of urea resulted in a lower risk of leaching N.