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Nitrous Oxide Emissions from an Ultisol of the Humid Tropics under Maize–Groundnut Rotation
Author(s) -
Khalil M.I.,
Rosenani A.B.,
Van Cleemput O.,
Fauziah C.I.,
Shamshuddin J.
Publication year - 2002
Publication title -
journal of environmental quality
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.888
H-Index - 171
eISSN - 1537-2537
pISSN - 0047-2425
DOI - 10.2134/jeq2002.1071
Subject(s) - nitrous oxide , ultisol , agronomy , tropics , soil water , sowing , nitrogen , crop , humid subtropical climate , crop rotation , manure , chemistry , environmental science , green manure , biology , ecology , soil science , medicine , organic chemistry , pathology
Nitrous oxide (N 2 O) contributes to global climate change and agricultural soils seem to be the major source. Lack of information led to this study on the influence of different amounts and sources of nitrogen on N 2 O emission from a maize ( Zea mays L.)–groundnut ( Arachis hypogae L.) crop rotation in an Ultisol of the humid tropics. The treatments were: inorganic N + crop residues (NC), inorganic N only (RN), and half of inorganic N + crop residues + chicken manure (NCM). The corresponding amount of N applied was 322, 180, and 400 kg ha −1 yr −1 , respectively. The N 2 O emissions depended on the amounts and types of N. A maximum peak (9889 ± 2106 μg N 2 O‐N m −2 d −1 ) was detected at 2 wk before maize sowing amended with chicken manure, showing a persistent influence on N transformations and N 2 O release. The mineral N from either applied source became low by 2 to 4 wk, coinciding with the small N 2 O fluxes or its consumption to a few isolated instances. The N 2 O flux significantly correlated with the mineral N and water‐filled pore spaces. The direct annual N 2 O emission was 3.94 ± 0.23, 1.90 ± 0.08, and 1.41 ± 0.07 kg N 2 O‐N ha −1 from the NCM, NC, and RN treatments, respectively. The corresponding N 2 O‐N loss of the applied N plus N fixed by groundnut was 0.83, 0.49, and 0.59%. Overestimations of direct annual N 2 O emission using the Intergovernmental Panel on Climate Change (IPCC) methodology suggest a location‐specific emission factor for variable N sources to be considered.