Ammonia volatilization losses in Tanzania grass fertilized with urea

• Autor(a) principal: Soares Filho, Cecilio Viega [UNESP]
• Data de Publicação: 2015
• Outros Autores: Cecato, Ulysses, Ribeiro, Ossival Lolato, Roma, Claudio Fabricio da Cruz, Beloni, Tatiane
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Repositório Institucional da UNESP
• Texto Completo: http://dx.doi.org/10.1590/S1519-99402015000100005; http://hdl.handle.net/11449/132975
• topic: Panicum maximum; Nitrogen fertilizer; Pasture; Panicum maximum; Fertilizante nitrogenado; Pastagem

Gaseous losses are the main factors affecting the efficiency of nitrogenous fertilizers in pastures. To evaluate NH3-N volatilization losses in Tanzania grass fertilized with urea in autumn, spring and summer, a completely randomized design with repeated measurements over time and fifteen replicates was used. Plots were represented by urea levels (50; 100 and 150 kg ha-1 N) and subplots by time after fertilization (1; 2; 3; 6; 9; 12 and 15 days). The interaction between fertilization leveland time after urea application was significant for the accumulated NH3-N volatilization. Urea application leads to higher percentage N losses in the first three days after application. The average cumulative NH3- N loss for the three occasions (different seasons of the year) was 28%, 20% and 16% of N applied for fertilizer doses of 50; 100 and 150 kg ha-1 of N, respectively. The season of the year influenced NH3-N loss pattern and volume, with the lowest values recorded in spring, followed by summer and autumn. The cumulative NH3-N volatilization loss varies from 78 to 90% up to the third day after application of the total NNH3 loss.