Emissão de óxidos de nitrogênio associada à aplicação de uréia sob plantio convencional e direto

Abstract

Resumo -O objetivo deste trabalho foi avaliar emissões de NO e N 2 O até cinco dias após a primeira fertilização de cobertura com uréia em milho, em Latossolo Vermelho argiloso distrófico, sob plantio convencional e direto. A adubação de cobertura foi de 60 kg ha . Não houve diferença significativa entre os plantios convencional e direto quanto à emissão dos óxidos de nitrogênio.Termos para indexação: óxido nítrico, óxido nitroso, fertilização nitrogenada, plantas de cobertura, irrigação, Cerrado. Nitrogen oxides emission related to urea broadcasting fertilization under conventional and no-tillage systemsAbstract -The objective of this work was to evaluate the NO and N 2 O emissions up to five days after the first nitrogen broadcasting fertilization with urea in a cornfield, in a Red Latosol, under conventional and no-tillage systems. The level of nitrogen broadcasting fertilization was of 60 kg ha -1. The experiment was conducted at Embrapa Cerrados, Planaltina, DF, Brazil, in a randomized block design, with three replications, beeing the third corn crop in rotation with soybean. NO and N 2 O fluxes were measured using PVC chambers installed in each plot. Higher NO fluxes were found immediately after (5.4 ng N cm -2 h -1) and three days (4.8 ng N cm -2 h -1 ) after N fertilization and irrigation. In the first day after fertilization, the NO emission decreased significantly to 1.9 ng N cm -2 h -1, and after five days, reached 1.2 ng N cm -2 h -1. N 2 O fluxes values were below the detection limit of 0.6 ng N cm -2 h -1 . No significant differences in nitrogen oxides fluxes were found between plots under conventional and no-tillage systems.

Nitrogen oxides and CO2 from an Oxisol cultivated with corn in succession to cover crops

“…N 2 O-N fluxes were calculated from the increase rate of the concentration, determined by linear regression based on the four samples taken. The detection limit of 0.6 ng N 2 O-N cm -2 h -1 was adopted in the present study, since similar system and methods were used (Carvalho et al, 2006). for three consecutive days after corn and cover crop management events and rainfall.…”

“…The use of N-fixing legumes, such as Crotalaria juncea L. and Mucuna pruriens (L.) DC., as cover crops in agricultural systems can incorporate more than 230 kg ha -1 N (Calegari et al, 2008). This practice could contribute to the reduction of the quantities of mineral N fertilizers applied, but its impacts on GHG emissions from the soil are still not widely evaluated in tropical agricultural systems (Carvalho, 2005;Carvalho et al, 2006;Metay et al, 2007;Cruvinel et al, 2011;Abdalla et al, 2014).…”

Nitrogen fluxes from irrigated common‑bean as affected by mulching and mineral fertilization

“…-and indirect ones -leaching, runoff, and atmospheric deposition (Cerri et al, 2009). Local assessment of GHG emissions from Brazilian agriculture systems have been reported (Carvalho et al, 2006;Metay et al, 2007;Jantalia et al, 2008;Zanatta et al, 2010;Cruvinel et al, 2011); however, the relative scarcity of data makes it difficult to assess the overall impact of irrigated common-bean under no-tillage on N 2 O-N and NH 3 -N fluxes in the Brazilian Cerrado.…”

Emissão de gases do efeito estufa em diferentes usos da terra no bioma Cerrado

“…Nesse sentido, alguns estudos (Varella et al, 2004;Carvalho et al, 2006;Metay et al, 2007) foram conduzidos para quantificar o fluxo dos gases em sistemas agrícolas e pastagens, comparados com a vegetação nativa. O objetivo deste estudo foi determinar a relação entre o fluxo dos GEE (CO 2 , N 2 O e CH 4 ) e as variáveis umidade, biomassa microbiana e teor de N-inorgânico em diferentes usos da terra no bioma Cerrado.…”