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The Extent of Soil Drying and Rewetting Affects Nitrous Oxide Emissions, Denitrification, and Nitrogen Mineralization
Author(s) -
Guo Xiaobin,
Drury Craig F.,
Yang Xueming,
Daniel Reynolds W.,
Fan Ruqin
Publication year - 2014
Publication title -
soil science society of america journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.836
H-Index - 168
eISSN - 1435-0661
pISSN - 0361-5995
DOI - 10.2136/sssaj2013.06.0219
Subject(s) - mineralization (soil science) , denitrification , soil water , nitrous oxide , nitrogen cycle , agronomy , nitrogen , characterisation of pore space in soil , environmental science , chemistry , water content , environmental chemistry , zoology , soil science , biology , porosity , organic chemistry , geotechnical engineering , engineering
Soil drying and subsequent rewetting induces N mineralization and denitrification, but the effects of the “extent” or “degree” of drying and rewetting remains poorly understood. The impacts of different degrees of soil drying (drying to 45, 30, 20, or 10% water‐filled pore space, WFPS) and subsequent rewetting (rewetting to 75 or 90% WFPS) on N 2 O emissions, denitrification, and net N mineralization were investigated. The highest N 2 O emissions (201 µg N 2 O‐N kg ‐1 ) occurred when the soils were dried to 10% WFPS followed by rewetting to 90% WFPS, whereas the lowest emissions (4.72 µg N 2 O‐N kg ‐1 ) occurred when the soil was dried to 45% WFPS followed by rewetting to 75% WFPS. When soil was rewetted from 10 to 90% WFPS, cumulative N 2 O emissions over 120 h were 7.4 times greater than when the soil was rewetted from 10 to 75% WFPS. The proportion of N 2 O evolved [N 2 O/(N 2 O+N 2 )] generally increased as the soil dried. Soil rewetting to 75% WFPS generally produced greater N 2 O/(N 2 O+N 2 ) ratios than rewetting to 90% WFPS. Net N mineralization rates in soils rewetted to 75% WFPS significantly increased from 0.78 mg N kg ‐1 d ‐1 for the soils dried to 45% WFPS to 1.69 mg N kg ‐1 d ‐1 for the soils dried to 10% WFPS. More extensive soil drying and more extensive rewetting stimulated N 2 O emissions and total denitrification losses, whereas net N mineralization rates were stimulated only by more extensive drying. Management practices which reduce extreme fluctuations in soil water content may consequently reduce N 2 O and total denitrification losses.