title: Straw return reduces yield-scaled N2O plus NO emissions from annual winter wheat-based cropping systems in the North China Plain.
abstract: Straw return in combination with synthetic N fertilizer is considered to be beneficial to soil fertility and crop yield. Such practice, however, can considerably modify soil microbial activity and relative C and N availability, both of which are known to regulate soil nitrous oxide (N2O) and nitric oxide (NO) emissions. Minimizing these emissions per unit of crop yield is a prerequisite to minimize the environmental footprint of agricultural production and thus, a policy objective. In our study, we quantified N2O and NO emissions and determined fertilizer-N use efficiencies (NUE) and crop yields of two double-cropping (summer maize/Welsh onion-winter wheat) systems with and without straw incorporation in the North China Plain. Relative to the fertilized treatment without straw amendments, straw incorporation showed a significant inhibitory effect on annual N2O emissions from the maize-wheat system (-31%), but no significant effect was observed for the Welsh onion-wheat system. However, straw return significantly reduced annual NO emissions by >30% for both systems. Meanwhile, straw return in both systems significantly increased the NUE and crop yields by 34-47% and 7-16%, respectively, as compared to the treatment without straw additions. Across the double-cropping systems, annual direct emission factors of N2O, NO and N2O+NO were 0.37-0.57%, 0.08-0.78% and 0.57-1.36%, respectively. Furthermore, a negative relationship between direct emission factors of N2O+NO and crop NUE was observed, highlighting the importance of optimizing NUE for reducing environmental risks of a cropping system. When expressing emissions on a yield basis, straw return significantly reduced annual yield-scaled N2O+NO emissions by 15-42% for both systems. Overall, our results show that the combined application of crop straw and synthetic N fertilizer is a promising N management strategy for maximizing crop yields while mitigating N-trace gas emissions.
authors.affiliation: State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, PR China; Institute for Meteorology and Climate Research, Atmospheric Environmental Research, Karlsruhe Institute of Technology, D-82467 Garmisch-Partenkirchen, Germany. Electronic address: zhishengyao@mail.iap.ac.cn.
authors.forename: Zhisheng
authors.initials: Z
authors.lastname: Yao
authors.affiliation: Key Laboratory for Yellow River and Huai River Water Environment and Pollution Control, Ministry of Education, School of Environment, Henan Normal University, Xinxiang 453007, PR China.
authors.forename: Guangxuan
authors.initials: G
authors.lastname: Yan
authors.affiliation: State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, PR China; College of Earth Science, University of Chinese Academy of Sciences, Beijing 100049, PR China.
authors.forename: Xunhua
authors.initials: X
authors.lastname: Zheng
authors.affiliation: State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, PR China.
authors.forename: Rui
authors.initials: R
authors.lastname: Wang
authors.affiliation: State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, PR China.
authors.forename: Chunyan
authors.initials: C
authors.lastname: Liu
authors.affiliation: Institute for Meteorology and Climate Research, Atmospheric Environmental Research, Karlsruhe Institute of Technology, D-82467 Garmisch-Partenkirchen, Germany.
authors.forename: Klaus
authors.initials: K
authors.lastname: Butterbach-Bahl
mesh_terms: D000383:Agriculture / Q000379:methods*; D002681:China; D018556:Crops, Agricultural / Q000254:growth & development; D005308:Fertilizers; D009569:Nitric Oxide / Q000032:analysis*; D009609:Nitrous Oxide / Q000032:analysis*; D018547:Plant Stems; D012987:Soil / Q000737:chemistry*; D014908:Triticum / Q000254:growth & development*; D003313:Zea mays / Q000254:growth & development
chemical_list: D005308:Fertilizers; D012987:Soil; D009569:Nitric Oxide; D009609:Nitrous Oxide
keywords: Crop straw; Emission factor; Nitric oxide; Nitrogen management; Nitrous oxide