Temporal changes in soil organic carbon contents and 未¹³C values under long-term maize-wheat rotation systems with various soil and climate conditions

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• 作者：Xu Tang^a ; Benjamin H. Ellert^b ; Xiying Hao^b ; Yibing Ma^c ; ^{ybma@caas.ac.cn} ; Elaine Nakonechny^b ; Jumei Li^c
• 关键词：Soil organic carbon ; 未13C ; Carbon cycling ; Maize ; Wheat
• 刊名：Geoderma
• 出版年：2012
• 期刊代码：28_00167061
• 类别：ear
• 出版时间：August, 2012
• 卷：183-184
• 期：Complete
• 页码：67-73
• 文件大小：336 K

摘要

Understanding soil organic carbon (SOC) decomposition and its replenishment by contrasting plant residues is critical to rationally manage soil carbon pools. Long-term (15 years) field experiments in maize-wheat (Zea mays L.-Triticum aestivum L.) rotation systems at diverse sites with contrasting climates and soil properties were conducted to evaluate the temporal dynamics of the C inputs, SOC concentrations and 未¹³C values. In the non-fertilized Control treatments mean annual C inputs (mainly roots) at the various sites ranged from 0.39 to 1.24 Mg ha^鈭?#xA0;1, and SOC contents remained largely unchanged during the 15 years study. However, results for the fertilized treatments indicated that SOC concentration increased by 1 g kg^鈭?#xA0;1 for every 24.3 (5.4-45.2) Mg C ha^鈭?#xA0;1 from roots alone in the NPK treatment and for every 29.4 (11.1-52.6) Mg C ha^鈭?#xA0;1 from crop roots plus straws in the NPKSt treatment. Furthermore, there was a positive correlation among changes in SOC, C₄-derived C and C₃-derived C and the 未¹³C values in all treatments across the four sites. Our results suggest that the 未¹³C value was a useful tool to quantify temporal changes of SOC from C₄ and C₃ plants, even when actual changes in soil C stock were small in these wheat-maize rotation cropping systems.