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Fallow Effects on Soil Carbon and Greenhouse Gas Flux in Central North Dakota
Author(s) -
Liebig M. A.,
Tanaka D. L.,
Gross J. R.
Publication year - 2010
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/sssaj2008.0368
Subject(s) - secale , summer fallow , agronomy , environmental science , greenhouse gas , cropping system , crop rotation , flux (metallurgy) , soil water , cropping , cover crop , soil carbon , chemistry , crop , biology , soil science , ecology , agriculture , organic chemistry
The inclusion of cover crops during fallow (i.e., green fallow) may mitigate greenhouse gas (GHG) emissions from dryland cropping systems. An investigation was conducted to quantify the effects of chemical and green fallow on soil organic C (SOC) and CO 2 , CH 4 , and N 2 O flux within spring wheat ( Triticum aestivum L.)–fallow (chemical fallow) and spring wheat–safflower ( Carthamus tinctorius L.)–rye ( Secale cereale L.) (green fallow) under no‐till management in west‐central North Dakota. Using static chamber methodology, flux measurements were made during 19 mo of the fallow period of each cropping system. Soil samples collected before initiation of flux measurements indicated no difference in SOC in the surface 10 cm between cropping systems. Additionally, differences in gas flux between cropping systems were few. Emission of CO 2 was greater under green fallow than chemical fallow during spring thaw until the termination of rye ( P = 0.0071). Uptake of atmospheric CH 4 was the dominant exchange process during the evaluation period, and was significantly ( P = 0.0124) greater under chemical fallow (−2.7 g CH 4 –C ha −1 d −1 ) than green fallow (−1.5 g CH 4 –C ha −1 d −1 ) following the termination of rye. Cumulative fluxes of CO 2 , CH 4 , and N 2 O did not differ between the chemical‐ and green‐fallow phases during the 19‐mo period ( P = 0.1293, 0.2629, and 0.9979, respectively). The results from this evaluation suggest there was no net GHG benefit from incorporating a rye cover crop during the fallow phase of a dryland cropping system under no‐till management.