title: Mass loss and chemical structures of wheat and maize straws in response to ultraviolet-B radiation and soil contact.
abstract: The role of photodegradation, an abiotic process, has been largely overlooked during straw decomposition in mesic ecosystems. We investigated the mass loss and chemical structures of straw decomposition in response to elevated UV-B radiation with or without soil contact over a 12-month litterbag experiment. Wheat and maize straw samples with and without soil contact were exposed to three radiation levels: a no-sunlight control, ambient solar UV-B, and artificially elevated UV-B radiation. A block control with soil contact was not included. Compared with the no-sunlight control, UV-B radiation increased the mass loss by 14-19% and the ambient radiation by 9-16% for wheat and maize straws without soil contact after 12 months. Elevated UV-B exposure decreased the decomposition rates of both wheat and maize straws when in contact with soil. Light exposure resulted in decreased O-alkyl carbons and increased alkyl carbons for both the wheat and maize straws compared with no-sunlight control. The difference in soil contact may influence the contribution of photodegradation to the overall straw decomposition process. These results indicate that we must take into account the effects of photodegradation when explaining the mechanisms of straw decomposition in mesic ecosystems.
authors.affiliation: State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China.|Jiujiang University, Jiujiang 332005, China.|University of Chinese Academy of Sciences, Beijing 100049, China.
authors.forename: Guixiang
authors.initials: G
authors.lastname: Zhou
authors.affiliation: State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China.
authors.forename: Jiabao
authors.initials: J
authors.lastname: Zhang
authors.affiliation: Department of Chemistry and Biochemistry, Old Dominion University, 4541 Hampton Boulevard, Norfolk, Virginia 23529, United States.
authors.forename: Jingdong
authors.initials: J
authors.lastname: Mao
authors.affiliation: State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China.
authors.forename: Congzhi
authors.initials: C
authors.lastname: Zhang
authors.affiliation: Institute of Soil and Water Resources and Environmental Science, College of Environmental &Resource Sciences, Zhejiang University, Hangzhou 310058, China.
authors.forename: Lin
authors.initials: L
authors.lastname: Chen
authors.affiliation: State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China.
authors.forename: Xiuli
authors.initials: X
authors.lastname: Xin
authors.affiliation: State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China.
authors.forename: Bingzi
authors.initials: B
authors.lastname: Zhao
mesh_terms: D018533:Biomass; D019906:Nuclear Magnetic Resonance, Biomolecular; D012987:Soil; D013997:Time Factors; D014908:Triticum / Q000737:chemistry* / Q000528:radiation effects*; D014466:Ultraviolet Rays; D003313:Zea mays / Q000737:chemistry* / Q000528:radiation effects*
chemical_list: D012987:Soil