title: Contributions of wheat and maize residues to soil organic carbon under long-term rotation in north China.
abstract: Soil organic carbon (SOC) dynamics in agro-ecosystem is largely influenced by cropping. However, quantifying the contributions of various crops has been lacking. Here we employed a stable isotopic approach to evaluate the contributions of wheat and maize residues to SOC at three long-term experimental sites in north China. Soil samples were collected from 0-20, 20-40, 40-60, 60-80 and 80-100 cm after 13 and 20 years of wheat-maize rotation, and SOC and its stable (13)C composition were determined. Our data showed that the δ(13)C value of SOC varied, on average, from -22.1‰ in the 0-20 cm to -21.5‰ in the 80-100 cm. Carbon input through maize residues ranged from 35% to 68% whereas the contribution of maize residues to SOC (0-40 cm) ranged from 28% to 40%. Our analyses suggested that the retention coefficient was in the range of 8.0-13.6% for maize residues and 16.5-28.5% for wheat residues. The two-fold higher retention coefficient of wheat versus maize residues was due to the differences in the quality of residues and probably also in the temperature during the growing season. Our study highlighted the importance of crop management on carbon sequestration in agricultural lands.
authors.affiliation: 1] Ministry of Agriculture Key Laboratory of Crop Nutrition and Fertilization, Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, Beijing 100081, China [2] Earth System Science Interdisciplinary Center, University of Maryland, College Park, MD 20740, USA [3] College of Resources and Environmental Sciences, China Agricultural University, Beijing 100094, China.
authors.forename: Jinzhou
authors.initials: J
authors.lastname: Wang
authors.affiliation: 1] College of Global Change and Earth System Science, Beijing Normal University, Xinjiekouwai Street No.19, Haidian District, Beijing 100875, and Joint Center for Global Change Studies, Beijing 100875, China [2] Earth System Science Interdisciplinary Center, University of Maryland, College Park, MD 20740, USA [3] State Key Laboratory of Desert and Oasis Ecology, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi, Xinjiang 830011, China.
authors.forename: Xiujun
authors.initials: X
authors.lastname: Wang
authors.affiliation: Ministry of Agriculture Key Laboratory of Crop Nutrition and Fertilization, Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, Beijing 100081, China.
authors.forename: Minggang
authors.initials: M
authors.lastname: Xu
authors.affiliation: College of Resources and Environmental Sciences, China Agricultural University, Beijing 100094, China.
authors.forename: Gu
authors.initials: G
authors.lastname: Feng
authors.affiliation: Ministry of Agriculture Key Laboratory of Crop Nutrition and Fertilization, Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, Beijing 100081, China.
authors.forename: Wenju
authors.initials: W
authors.lastname: Zhang
authors.affiliation: College of Natural Resources and Environment, Northwest Agricultural and Forestry Science and Technology University, Yangling, Shaanxi 712100, China.
authors.forename: Xueyun
authors.initials: X
authors.lastname: Yang
authors.affiliation: Institute of Plant Nutrition, Resources and Environment, Henan Academy of Agricultural Sciences, Zhengzhou, Henan 450002, China.
authors.forename: Shaomin
authors.initials: S
authors.lastname: Huang
mesh_terms: D002244:Carbon / Q000032:analysis*; D002247:Carbon Isotopes; D002681:China; D002980:Climate; D009930:Organic Chemicals / Q000032:analysis*; D018517:Plant Roots / Q000737:chemistry; D018520:Plant Shoots / Q000737:chemistry; D012399:Rotation; D012987:Soil / Q000737:chemistry*; D013997:Time Factors; D014908:Triticum / Q000254:growth & development*; D035501:Uncertainty; D003313:Zea mays / Q000254:growth & development*
chemical_list: D002247:Carbon Isotopes; D009930:Organic Chemicals; D012987:Soil; D002244:Carbon