%0 Journal Article
%A Gomes, J.
%A Brüggemann, N.
%A Dick, D. P.
%A Pedroso, G. M.
%A Veloso, M.
%A Bayer, C.
%T Urea and legume residues as 15N-N2O sources in a subtropical soil
%J Soil research
%V 57
%N 3
%@ 1838-675X
%C Collingwood, Victoria
%I CSIRO
%M FZJ-2019-03494
%P 287 - 293
%D 2019
%X In this work, we used the 15N labelling technique to identify the sources of N2O emitted by a subtropical soil following application of mineral nitrogen (N) fertiliser (urea) and residues of a legume cover crop (cowpea). For this purpose, a 45-day incubation experiment was conducted by subjecting undisturbed soil cores from a subtropical Acrisol to five different treatments: (1) control (no crop residue or fertiliser-N application); (2) 15N-labelled cowpea residue (200 μg N g–1 soil); (3) 15N-labelled urea (200 μg N g–1 soil); (4) 15N-labelled cowpea residue (100 μg N g–1 soil) + unlabelled urea (100 μg N g–1 soil); and (5) unlabelled cowpea residue (100 μg N g–1 soil) + 15N-labelled urea (100 μg N g–1 soil). Cores were analysed for total N2O formation, δ15N-N2O and δ18O-N2O by continuous flow isotope ratio mass spectrometry, as well as for total NO3–-N and NH4+-N. Legume crop residues and mineral fertiliser increased N2O emissions from soil to 10.5 and 9.7 µg N2O-N cm–2 respectively, which was roughly six times the value for control (1.5 µg N2O-N cm–2). The amount of 15N2O emitted from labelled 15N-urea (0.40–0.45% of 15N applied) was greater than from 15N-cowpea residues (0.013–0.015% of 15N applied). Unlike N-poor crop residues, urea in combination with N-rich residues (cowpea) failed to reduce N2O emissions relative to urea alone. Legume cover crops thus provide an effective mitigation strategy for N2O emissions in relation to mineral N fertilisation in climate-smart agriculture. Judging by our inconclusive results, however, using urea in combination with N-rich residues provides no clear-cut environmental advantage.
%F PUB:(DE-HGF)16
%9 Journal Article
%U <Go to ISI:>//WOS:000463909500009
%R 10.1071/SR18300
%U https://juser.fz-juelich.de/record/863429