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Ammonia volatilization from nitrogen fertilizers applied to sugarcane straw

2017; UNIVERSIDADE FEDERAL DO CEARÁ; Volume: 48; Issue: 3 Linguagem: Inglês

10.5935/1806-6690.20170048

1982-9329

Rafael Otto, Eduardo Zavaschi, Gerson Marquesi de Souza Netto, Bianca de Almeida Machado, Acácio Bezerra de Mira,

Soil Management and Crop Yield

Maintenance of crop residues over soil surface under conservational systems limits incorporation of nitrogen fertilizers into the soil.Application of urea over crop residues enhance N-NH 3 volatilization losses, justifying the usage of urease inhibitors or N sources less susceptible to volatilization under such conditions.This study aimed to evaluate volatilization losses from N sources applied over sugarcane straw.A field trial was carried out in a sugarcane field in Iracemapolis, Sao Paulo on a Typic Kandiudox in June 2014.We used a complete block experimental design, with seven treatments and four replications.Treatments included Control [CO], ammonium nitrate [AN], NS30 TM (ammonium nitrate-75% and ammonium sulfate-25% fused mixture) [NS30 TM ], ammonium nitrate plus ammonium sulfate (ammonium nitrate-75% and ammonium sulfate-25% physical mixture) [AN-AS], urea [UR], urea treated with 0.4% Cu and 0.15% B [UR-CuB], urea treated with 530 mg kg -1 of NBPT [UR-NBPT].Treatments were applied at rate of 100 kg ha -1 N (except CO).Volatilization losses were quantified up to 30 days after fertilization (DAF).Maximum N-NH 3 occurred 16 DAF for UR and UR-CuB and 20 DAF for UR-NBPT.Accumulated N-NH 3 losses ranged from 20% (UR), 17% (UR-CuB), and 14% (UR-NBPT) of applied N; nonamidic sources showed losses lower than 1%.Adding urease inhibitor to urea shows potential in reducing volatilization losses even under application over large amounts of straw.