Author(s):
Carneiro, J.P. 
; Coutinho, J. ; Trindade, H.
Date: 2013
Persistent ID: http://hdl.handle.net/10400.11/2593
Origin: Repositório Científico do Instituto Politécnico de Castelo Branco
Subject(s): GHG emissions; Nitrogen; Soil fertilization; Nitrification inhibitor
Description
N2O emissions are affected by several factors, including type of fertilizer,
edafo-climatic conditions and mitigation measures applied. A field experiment was
carried out in central Portugal for two consecutive years, to evaluate the effect over soil
N2O emissions originated from the application of cattle slurry (CS) to a double-cropping
system producing maize and oats. The use of a nitrification inhibitor (DCD) was
evaluated as emission mitigation measure. A mineral fertilizer treatment (MIN) and a
Control were included and the DCD effects were tested together with MIN (MIN+DCD)
and CS (CS+DCD). Total N input was equal for all fertilizing treatments (oat 80 kg N ha-
1; maize 170 kg N ha-1). N2O fluxes were measure on 165 sampling dates, using a photoacoustic
spectroscopic infrared gas analyzer. The most important fluxes were observed 8-
10 days after fertilizer incorporation and during the following 20-40 days. Annual N2O-N
losses were higher in the first year, with a wettest autumn and a warmer summer than
usual. The highest values were measured with the use of mineral fertilizers (4.65 and 4.21
kg N ha-1 in MIN+DCD and MIN, respectively), which were 60-70% higher than those
measured with slurry application or without fertilization (1.85, 1.55 and 1.33 kg N ha-1 in
CS+DCD, CS and Control, respectively). Mean annual values of emission factor based
on N application (EF) were 0.76, 0.63, 0.12 and 0.07%, in MIN+DCD, MIN, CS and
CS+DCD, respectively. The DCD use, namely with mineral fertilizer, didn’t produce an
evident effect on total N2O losses.
