Influence of current and previous crops on soil basal and potential denitrification rates |
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Authors: | Xiaobin Guo Craig F Drury Xueming Yang W Daniel Reynolds Renduo Zhang |
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Institution: | (1) School of Environmental Science and Engineering, Sun Yat-sen University, Guangzhou, 510275, People’s Republic of China;(2) Greenhouse and Processing Crops Research Centre, Agriculture & Agri-Food Canada, Harrow, ON, Canada, N0R 1G0; |
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Abstract: | Soil and crop management including crop rotation influences available organic carbon and soil nitrate levels, which may in
turn affect denitrification losses from soils. The objective of this paper was to determine how the current and previous crop
affect denitrification by comparing the basal denitrification rate (BDR), denitrification rate with added nitrate (DAN), and
potential denitrification rate (PDR) (amended with glucose and nitrate) of a clay loam soil under monoculture corn (C), soybean
(S), and winter wheat (WW) with or without underseeded red clover (RC) and under each phase of a 2-year crop rotation (C-S)
and two 3-year crop rotations (C-S-WW, C-S-WW+RC). The BDRs were greater in the 3-year C-S-WW rotation treatments than in
the 2-year C-S rotation and monoculture C, S, and WW treatments. The WW+RC phase of the C-S-WW+RC treatment was found to have
a greater BDR and DAN than the corn phase of the rotation. Available organic carbon was found to limit denitrification in
the BDR and DAN incubations as evidenced by the 2- to 21-fold increase in denitrification when glucose was added in the PDR
assay. Further, the significant relationship between soil respiration and BDR suggests that available carbon was a limiting
factor. This study found that both the current crop and previous crops in a rotation affected soil denitrification rates substantially;
and that denitrification rate was increased when a mixture of crop residues were added to soil (i.e., from growing crops in
rotation) relative to when only a single residue was added (i.e., monoculture cropping). |
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