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Impacts of Early‐ and Late‐Terminated Cover Crops on Gas Fluxes
Author(s) -
Ruis Sabrina J.,
BlancoCanqui Humberto,
Jasa Paul J.,
Ferguson Richard B.,
Slater Glen
Publication year - 2018
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/jeq2018.02.0066
Subject(s) - loam , agronomy , secale , environmental science , sowing , cover crop , soil water , particulate organic matter , biomass (ecology) , organic matter , hydrology (agriculture) , chemistry , soil science , biology , organic chemistry , geotechnical engineering , engineering
Cover crops (CCs) could alter soil processes, but the effects of early versus late termination of CCs on gas fluxes are not well known. We evaluated temporal changes in fluxes of CO 2 , N 2 O, and CH 4 and related soil properties in no‐till corn ( Zea mays L.) with and without winter rye ( Secale cereale L.) CCs that were terminated early (30 d before planting) or late (at planting) in a rainfed silty clay loam and an irrigated silt loam in Nebraska from April 2016 to June 2017. Gas fluxes, soil temperature, and soil water content were measured biweekly to monthly, and wet aggregate stability and particulate organic matter concentrations were measured seasonally. We also compared our results with a global literature review. Late‐terminated CCs did not affect CH 4 fluxes but increased daily CO 2 fluxes by 59% compared with no CC at both sites and N 2 O fluxes by 92% at the rainfed site only. Early termination did not affect gas fluxes. Termination date did not affect cumulative fluxes and had minimal effects on soil properties. The literature review supports our study results, which indicate that CC effects on (i) CO 2 fluxes are driven by plant respiration during the CC growing period, and (ii) N 2 O and CH 4 fluxes are minimal under grass CCs. Overall, under no‐till, CC termination date has small effects on N 2 O and CH 4 fluxes, but late CC termination can increase CO 2 fluxes in spring due to greater biomass yield compared with early termination. Core Ideas Early‐terminated cover crops had limited effects on CO 2 fluxes in this study. Late‐terminated cover crops increased CO 2 flux mainly in spring due to higher cover crop biomass yield. Cover crop termination effects on N 2 O and CH 4 fluxes were generally nonsignificant. Our literature review showed cover crops affected CO 2 mostly during their growing period. Our literature results also showed grass cover crops had limited effects on N 2 O.