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Impact of Kura Clover Living Mulch on Nitrous Oxide Emissions in a Corn–Soybean System
Author(s) -
Turner Peter A.,
Baker John M.,
Griffis Timothy J.,
Venterea Rodney T.
Publication year - 2016
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/jeq2016.01.0036
Subject(s) - agronomy , nitrous oxide , leaching (pedology) , mulch , environmental science , greenhouse gas , perennial plant , tillage , fertilizer , pasture , soil water , chemistry , biology , ecology , organic chemistry , soil science
Nitrous oxide (N 2 O), produced primarily in agricultural soils, is a potent greenhouse gas and is the dominant ozone‐depleting substance. Efforts to reduce N 2 O emissions are underway, but mitigation results have been inconsistent. The leguminous perennial kura clover ( Trifolium ambiguum M. Bieb.) (KC) can grow side‐by‐side with cash crops in rotational corn ( Zea mays L.)–soybean ( Glycine max L.) systems. With biological nitrogen fixation, KC provides land managers an opportunity to reduce external fertilizer inputs, which may diminish problematic N 2 O emissions. To investigate the effect of a KC living mulch on N 2 O emissions, automated soil chambers coupled to a N 2 O analyzer were used to measure hourly fluxes from April through October in a 2‐yr corn–soybean (CS) rotation. Emissions from the KC treatment were significantly greater than those from the conventional CS treatment despite the fact that the KC treatment received substantially less inorganic nitrogen fertilizer. A seasonal tradeoff was observed with the KC treatment wherein emissions before strip‐tillage were reduced but were surpassed by high losses after strip‐tillage and postanthesis. These results represent the first reported measurements of N 2 O emissions from a KC‐based living mulch. The findings cast doubt on the efficacy of KC for mitigating N 2 O loss in CS systems. However, if KC reduces nitrate leaching losses, as has been reported elsewhere, it may result in lower indirect (offsite) N 2 O emissions. Core Ideas Kura clover living mulch increased total N 2 O emissions. Nitrogen scavenging by the kura clover living mulch may have reduced spring N 2 O emissions. Emissions in the kura clover treatment were affected by soil disturbance and plant stress. Corn and soybean yield were only marginally affected by kura clover living mulch.