Data/hora: 06/06/2024 02:35:47

Provedor de dados: 	90	
País: 	Brazil	
Título: 	Emissions of Nitrous Oxide and Methane in a Subtropical Ferralsol Subjected to Nitrogen Fertilization and Sheep Grazing in Integrated Crop-Livestock System	
Autores: 	Piva,Jonatas Thiago; Sartor,Laércio Ricardo; Sandini,Itacir Eloi; Moraes,Anibal de; Dieckow,Jeferson; Bayer,Cimélio; Rosa,Carla Machado da.	
Data: 	2019-01-01	
Ano: 	2019	
Palavras-chave: 	Nitrate; Ammonium; Water filled pore space; Sheep.	
Resumo: 	ABSTRACT Brazilian agriculture contributes significantly to nitrous oxide (N2O) and methane (CH4) emissions, so the understanding of such emissions at the field is crucial for mitigation strategies. This study quantified the impact of N application and sheep grazing on the N2O and CH4 emissions from a subtropical Ferralsol under an integrated crop-livestock (ICL) management system. In a long-term experiment in southern Brazil, gaseous fluxes were measured during a year-long cycle of ryegrass (Lolium multiflorum) plus oats (Avena sativa) winter pasture and a summer crop of common beans (Phaseolus vulgaris). Three rates of urea-nitrogen (0, 75, and 150 kg ha-1) were applied to the winter-pasture, which was subjected to two sheep grazing levels (continuously grazed, and ungrazed). The experiment had a complete randomized block design with three replicates. Soil N2O and CH4 fluxes were measured with closed static-chambers (0.20 m high × 0.25 m in diameter). Nitrous oxide emission peaks occurred 28 days after N application and increased with N application rate. Accordingly, the cumulative N2O emissions averaged across grazed and ungrazed treatments increased from 0.45 kg ha-1 in the control soil to 1.78 and 2.10 kg ha-1 after application of 75 and 150 kg ha-1, respectively. The N2O emission factors were 1.7 and 1.1 % when the N rates were 75 and 150 kg ha-1, respectively. The cumulative average N2O emission for all N rates was 2.09 kg ha-1 in ungrazed pasture, but it was reduced by 62 % with grazing to 0.80 kg ha-1, perhaps because of a possible denitrification of N2O to N2 associated with soil compaction from trampling. Overall, fertilizer-N is an important source of N2O from soil under ICL based on sheep grazing, with emission factors consistent with the IPCC’s default of 1 % (0.3-3.0 %). Grazing reduced the emission of soil N2O, but the underlying cause of that reduction needs to be better understood.	
Tipo: 	Info:eu-repo/semantics/article	
Idioma: 	Inglês	
Identificador: 	http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-06832019000100520	
Editor: 	Sociedade Brasileira de Ciência do Solo	
Relação: 	10.1590/18069657rbcs20180140	
Formato: 	text/html	
Fonte: 	Revista Brasileira de Ciência do Solo  v.43 2019	
Fonte: 	info:eu-repo/semantics/openAccess