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Volume 106, Issue 3 p. 968-980
Agronomy, Soils & Environmental Quality

Nitrogen Management and Methane Emissions in Direct-Seeded Rice Systems

Cameron M. Pittelkow

Corresponding Author

Cameron M. Pittelkow

Dep. of Plant Sciences, Univ. of California, Davis, One Shields Ave., Davis, CA, 95616

Corresponding author ([email protected]).

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Yacov Assa

Yacov Assa

Dep. of Land, Air and Water Resources, Univ. of California, Davis, One Shields Ave., Davis, CA, 95616

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Martin Burger

Martin Burger

Dep. of Land, Air and Water Resources, Univ. of California, Davis, One Shields Ave., Davis, CA, 95616

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Randall G. Mutters

Randall G. Mutters

Univ. of California Cooperative Extension, Division of Agriculture and Natural Resources, 1111 Franklin St., Oakland, CA, 94607

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Chris A. Greer

Chris A. Greer

Univ. of California Cooperative Extension, Division of Agriculture and Natural Resources, 1111 Franklin St., Oakland, CA, 94607

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Luis A. Espino

Luis A. Espino

Univ. of California Cooperative Extension, Division of Agriculture and Natural Resources, 1111 Franklin St., Oakland, CA, 94607

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James E. Hill

James E. Hill

Dep. of Plant Sciences, Univ. of California, Davis, One Shields Ave., Davis, CA, 95616

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William R. Horwath

William R. Horwath

Dep. of Land, Air and Water Resources, Univ. of California, Davis, One Shields Ave., Davis, CA, 95616

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Chris van Kessel

Chris van Kessel

Dep. of Plant Sciences, Univ. of California, Davis, One Shields Ave., Davis, CA, 95616

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Bruce A. Linquist

Bruce A. Linquist

Dep. of Plant Sciences, Univ. of California, Davis, One Shields Ave., Davis, CA, 95616

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First published: 01 May 2014
Citations: 20

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Abstract

Rice (Oryza sativa L.) establishment systems based on resource-conserving production practices are gaining popularity globally. To investigate the potential for improved N management and mitigation of methane (CH4) emissions, field experiments were conducted in California on three crop establishment systems: water-seeded (WS) conventional, WS stale seedbed, and drill-seeded (DS) stale seedbed. Fertilizer nitrogen recovery efficiency (NRE) and rice yield as affected by N rate, source, and application timing were evaluated for 2 yr in each system. Methane emissions were monitored over a full annual rice production cycle (growing season plus fallow period). Results indicated that neither split N applications nor ammonium sulfate increased yields or NRE compared with a single application of urea, regardless of system. However, the economic optimum N rate increased by approximately 30 kg N ha−1 in WS stale seedbed compared with the conventional system. Since NRE generally remained similar across N treatments that maximized yields, applying the appropriate N rate as a single dose before the permanent flood would satisfy both agronomic and environmental goals of N management within each system. Both WS systems resulted in similar growing season CH4 emissions. However, the DS system reduced CH4 emissions by 47% compared with the conventional WS system, possibly due to a decreased period of anaerobic soil conditions. This study highlights the importance of assessing benefits as well as tradeoffs when evaluating opportunities for increasing the sustainability of direct-seeded establishment systems with respect to N management and CH4 emissions.