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Methane Emissions from Drill‐Seeded, Delayed‐Flood Rice Production on a Silt‐Loam Soil in Arkansas
Author(s) -
Rogers Christopher W.,
Brye Kristofor R.,
Norman Richard J.,
Gbur Edward E.,
Mattice John D.,
Parkin Timothy B.,
Roberts Trenton L.
Publication year - 2013
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/jeq2012.0502
Subject(s) - loam , environmental science , growing season , agronomy , methane , silt , vegetation (pathology) , nitrogen , hydrology (agriculture) , soil water , chemistry , soil science , geology , biology , medicine , paleontology , geotechnical engineering , organic chemistry , pathology
Rice ( Oryza sativa L.) production is unique among staple food crops because the majority of the growing season typically occurs under flooded‐soil conditions. Flooding the soil leads to anaerobic conditions, which are a precursor to methane (CH 4 ) production. However, no known research has investigated CH 4 emissions from the drill‐seeded, delayed‐flood rice production system common in Arkansas, the leading rice‐producing state in the United States. Therefore, research was conducted in 2011 to determine the effects of vegetation (rice and bare soil), chamber location (in‐ and between‐rice rows), and nitrogen (N) fertilization (optimal and no N) on CH 4 emissions from a silt‐loam soil. Methane fluxes measured weekly from flooding until flood release were affected by vegetation, chamber location, and sample date ( P < 0.05). In‐row CH 4 fluxes were <0.7 mg CH 4 –C m −2 h −1 until 20 d after flooding (DAF) and <1.0 mg CH 4 –C m −2 h −1 from between‐row and bare soil until 41 DAF and were unaffected by fertilization over time. The largest weekly measured CH 4 flux (31.9 mg CH 4 –C m −2 h −1 ) was observed from in‐row rice at 41 DAF. Post–flood‐release CH 4 fluxes were affected by vegetation, fertilization, chamber placement, and sample date ( P < 0.05) and accounted for approximately 3 to 7% of the season‐long CH 4 emissions. Methane emissions averaged 195 kg CH 4 –C ha −1 per growing season and were unaffected by fertilization. Direct measurement of CH 4 emissions from drill‐seeded, delayed‐flood rice grown on a silt‐loam soil will improve the accuracy of assessments of the carbon footprint and long‐term sustainability of rice.