| 重庆农田土壤有机碳稳定性同位素空间分布特征 |
| 摘要点击 1838 全文点击 511 投稿时间：2021-09-11 修订日期：2021-11-08 |
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| 中文关键词 农田 土壤有机碳(SOC) 稳定性同位素组成 空间分布 主控因素 |
| 英文关键词 farmland soil organic carbon (SOC) stable isotope composition spatial variation controlling factors |
| 作者 | 单位 | E-mail | | 廖宇琴 | 西南大学资源环境学院, 重庆 400716 | 1297524810@qq.com | | 龙娟 | 西南大学资源环境学院, 重庆 400716 | | | 木志坚 | 西南大学资源环境学院, 重庆 400716
重庆市农业资源与环境研究重点实验室, 重庆 400716
农业部西南耕地保育重点实验室, 重庆 400716 | muzj@swu.edu.cn | | 文首鑫 | 西南大学资源环境学院, 重庆 400716 | | | 李翠莲 | 西南大学资源环境学院, 重庆 400716 | | | 杨志敏 | 西南大学资源环境学院, 重庆 400716
重庆市农业资源与环境研究重点实验室, 重庆 400716 | | | 赵秀兰 | 西南大学资源环境学院, 重庆 400716
重庆市农业资源与环境研究重点实验室, 重庆 400716 | |
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| 中文摘要 |
| 对重庆182个典型农田土壤剖面有机碳稳定性同位素组成（δ13 CSOC）的测定结果表明，所有剖面土壤δ13 CSOC值均随采样深度增加逐渐趋正，表、中和底层均值分别为（-23.63±1.53）‰、（-22.43±1.59）‰和（-21.42±1.90）‰.就地域而言，渝东北土壤δ13 CSOC值偏负程度最高，渝中土壤则偏正.水田δ13 CSOC值明显偏负，旱地偏正，水旱轮作则居中；三者表层土壤δ13 C均值分别为（-25.32±0.93）‰、（-23.17±1.37）‰和（-24.75±1.28）‰；不同类型土壤表层δ13 C均值依序为：水稻土<潮土<紫色土<石灰（岩）土<黄壤.回归树分析表明，表层土壤δ13 CSOC值主要受作物类型控制，中底层则主要与土壤类型有关；其它因素如土壤性质（总氮、SOC和pH）和气象条件（降雨量和气温）等也有一定的影响.换言之，表层土壤稳定性碳同位素分布主要受碳源的影响，中底层主要与土壤碳循环过程有关. |
| 英文摘要 |
| Soil was sampled from 182 profiles in typical farmlands of Chongqing and analyzed for the stable carbon isotope composition of organic matter (δ13CSOC). The results showed that the values of δ13CSOC for each soil profile were gradually increasing with increasing soil depth, and the mean values were (-23.63±1.53)‰, (-22.43±1.59)‰, and (-21.42±1.90)‰ for surface, middle, and bottom layers, respectively. The δ13CSOC values in the northeastern region of Chongqing tended to be more negative, whereas those in central Chongqing were less negative. Paddy fields showed the most negative values of δ13CSOC, followed by rice-upland rotating fields and upland fields, with the average being (-25.32±0.93)‰, (-23.17±1.37)‰, and (-24.75±1.28)‰ for the surface layers, respectively. For different soil types, the δ13C values in the surface layers were in the order of paddy soilδ13CSOC in surface soils, and soil types mainly affected that in the middle- and bottom-layer soils. Other factors, such as soil properties (TN, SOC, and pH) and meteorological conditions (precipitation and air temperature) played only minor roles in the variation of δ13CSOC. In short, the stable isotope composition of organic carbon in the surface soils was primarily controlled by the input carbon source, whereas that in the deeper layers was closely linked with carbon cycling processes within the soils. |
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