title: Carbon accumulation in arid croplands of northwest China: pedogenic carbonate exceeding organic carbon.
abstract: Soil carbonate (SIC) exceeds organic carbon (SOC) greatly in arid lands, thus may be important for carbon sequestration. However, field data for quantifying carbonate accumulation have been lacking. This study aims to improve our understanding of SIC dynamics and its role in carbon sequestration. We analyzed two datasets of SOC and SIC and their (13)C compositions , one with over 100 soil samples collected recently from various land uses in the Yanqi Basin, Xinjiang, and the other with 18 archived soil samples from a long-term experiment (LTE) in Pingliang, Gansu. The data from the Yanqi Basin showed that SOC had a significant relationship with SIC and pedogenic carbonate (PIC); converting shrub land to cropland increased PIC stock by 5.2 kg C m(-2), which was 3.6 times of that in SOC stock. The data from the LTE showed greater accumulation of PIC (21-49 g C m(-2) year(-1)) than SOC (10-39 g C m(-2) year(-1)) over 0-20 cm. Our study points out that intensive cropping in the arid and semi-arid regions leads to an increase in both SOC and PIC. Increasing SOC through straw organic amendments enhances PIC accumulation in the arid cropland of northwestern China.
authors.affiliation: 1] State Key Laboratory of Desert and Oasis Ecology, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi, Xinjiang 830011, China [2] 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 [3] Earth System Science Interdisciplinary Center, University of Maryland, College Park, MD 20740, USA.
authors.forename: Xiujun
authors.initials: X
authors.lastname: Wang
authors.affiliation: 1] State Key Laboratory of Desert and Oasis Ecology, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi, Xinjiang 830011, China [2] College of Agriculture, Shihezi University, Shihezi 832003, Xinjiang, China.
authors.forename: Jiaping
authors.initials: J
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: 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: Dryland Agriculture Institute, Gansu Academy of Agricultural Sciences, Lanzhou 730070, Gansu, China.
authors.forename: Tinglu
authors.initials: T
authors.lastname: Fan
authors.affiliation: School of Resource and Environment, Northeast Agricultural University, Harbin Heilongjiang 150030, China.
authors.forename: Juan
authors.initials: J
authors.lastname: Zhang
mesh_terms: D002244:Carbon / Q000032:analysis*; D002247:Carbon Isotopes / Q000737:chemistry; D002681:China; D018556:Crops, Agricultural; D006863:Hydrogen-Ion Concentration; D012987:Soil / Q000737:chemistry*
chemical_list: D002247:Carbon Isotopes; D012987:Soil; D002244:Carbon