Soil organic carbon loss and selective transportation under field simulated rainfall events.
Soil organic carbon loss and selective transportation under field simulated rainfall events.
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现场模拟降雨事件下的土壤有机碳损失和选择性运输
DOI：
10.1371/journal.pone.0105927
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发表时间：
2014
期刊：
影响因子：
3.7
通讯作者：
Zeng G
中科院分区：
文献类型：
--
作者：
Nie X;Li Z;Huang J;Huang B;Zhang Y;Ma W;Hu Y;Zeng G
研究土壤侵蚀过程中土壤有机碳的横向迁移规律，有助于加深对全球碳收支的认识。通过田间小区模拟降雨试验，研究了不同降雨强度和耕作措施下土壤有机碳的侧向迁移规律。在宽2 m ×长5 m的HI-NT、LI-NT和LI-CT三个试验小区中，设置两种降雨强度（高强度（HI）和低强度（LI））和两种耕作措施（免耕（NT）和常规耕作（CT））。降雨持续60 min后，产流，产沙量和径流量的测量和采样，在6 min的时间间隔。测定了泥沙和径流中有机碳含量以及泥沙粒径分布。结果表明，在所有事件中，大部分侵蚀有机碳（OC）以沉积物结合态有机碳的形式流失。LI-NT事件的SOC丢失量是LI-CT事件的12.76倍，而HI-NT事件的SOC丢失量是LI-NT事件的3.25倍。这些结果表明，传统耕作以及较低的降雨强度可以减少短期土壤侵蚀过程中的SOC流失量。同时，各事件侵蚀沉积物中有机碳均富集，LI事件沉积物中有机碳的富集率（ERoc）高于HI事件，而LI-CT和LI-NT事件沉积物中的ERoc曲线相似。此外，ERoc和不同粒径的泥沙颗粒之间的显着的相关性只观察到在HI-NT事件。这表明，有机碳的富集是依赖于侵蚀过程，并针对不同的侵蚀过程的具体富集机制，应在未来的研究。
The study on the lateral movement of soil organic carbon (SOC) during soil erosion can improve the understanding of global carbon budget. Simulated rainfall experiments on small field plots were conducted to investigate the SOC lateral movement under different rainfall intensities and tillage practices. Two rainfall intensities (High intensity (HI) and Low intensity (LI)) and two tillage practices (No tillage (NT) and Conventional tillage (CT)) were maintained on three plots (2 m width × 5 m length): HI-NT, LI-NT and LI-CT. The rainfall lasted 60 minutes after the runoff generated, the sediment yield and runoff volume were measured and sampled at 6-min intervals. SOC concentration of sediment and runoff as well as the sediment particle size distribution were measured. The results showed that most of the eroded organic carbon (OC) was lost in form of sediment-bound organic carbon in all events. The amount of lost SOC in LI-NT event was 12.76 times greater than that in LI-CT event, whereas this measure in HI-NT event was 3.25 times greater than that in LI-NT event. These results suggest that conventional tillage as well as lower rainfall intensity can reduce the amount of lost SOC during short-term soil erosion. Meanwhile, the eroded sediment in all events was enriched in OC, and higher enrichment ratio of OC (ERoc) in sediment was observed in LI events than that in HI event, whereas similar ERoc curves were found in LI-CT and LI-NT events. Furthermore, significant correlations between ERoc and different size sediment particles were only observed in HI-NT event. This indicates that the enrichment of OC is dependent on the erosion process, and the specific enrichment mechanisms with respect to different erosion processes should be studied in future.