氧化铁对红壤溅蚀的影响及微观机制

Splash erosion is responsible for initiating water loss and soil erosion, influencing water erosion on slope greatly. Aggregate stability affected by iron oxides is a key factor influencing splash erosion. In our study, we will select typical red soil hilly regions in Jiangxi Province as study area, in which splash erosion is common. Surface red soil samples with diverse splash erosion degree will be collected. After that, aggregates in different size fractions will be firstly sorted out by dry and wet sieving methods. Then, correlation between the content of iron oxides with different crystallinity and the mechanical stability and water stability of soil aggregates will be investigated. Moreover, influences of iron oxides amendments on soil aggregates and rainfall splash erosion will be looked into using combined method of incubation and artificial stimulated rainfall. Based on this, interface interactions between iron oxides and clay minerals in the soil aggregates will be discussed by using several micro analysis techniques, and effects of their interactions on soil aggregate stability will be investigated. Then, the effect mechanisms of iron oxides on the aggregate stability of red soils and rainfall splash erosion will be elucidated. The results would contribute to expand the understanding of the rainfall splash erosion process and its mechanisms of red soils, and provide theoretical guidance for prevention and control of soil degradation, soil and water conservation in red soil region.

土壤溅蚀是水土流失的初期阶段，对坡面水蚀具有重要的影响作用。团聚体稳定性是影响土壤溅蚀的关键要素，而氧化铁又是影响团聚体稳定性的重要因素。本项目以溅蚀现象较普遍的江西典型红壤丘陵区为研究区域，采集不同溅蚀程度的红壤样品，以氧化铁的作用过程与机制为切入点，采用干筛、湿筛法分选出不同粒径团聚体，分析不同粒径团聚体中不同晶形氧化铁与力稳定性、水稳定性的定量关系；通过室内培养、人工模拟降雨相结合，研究不同晶形氧化铁添加对团聚体稳定性和降雨溅蚀的影响，建立三者的内在联系；在此基础上，综合运用环境分子手段从微观角度探讨红壤氧化铁与黏粒在界面上的交互作用过程和对红壤团聚体稳定性的影响，明确氧化铁对红壤团聚体稳定性和降雨溅蚀的内在影响机制。研究结果将有助于深化对红壤降雨溅蚀过程及其机制的理解，为红壤地区的土壤退化防治、水土保持等提供理论指导。

土壤溅蚀是水土流失的初期阶段，对坡面水蚀具有重要的影响作用。团聚体稳定性是影响土壤溅蚀的关键要素，而氧化铁/铝又是影响团聚体稳定性的重要因素。本项目以氧化铁的作用过程与机制为切入点，采用干筛、湿筛法分选出不同粒径团聚体，建立了不同粒径团聚体中不同晶形氧化铁/铝与力稳定性、水稳定性的定量关系；通过室内培养、人工模拟降雨相结合，研究了不同晶形氧化铁添加对团聚体稳定性和降雨溅蚀的影响，建立了三者的内在联系。主要研究结果包括：无定形氧化铁(Feo)含量在0.25-2和2-5 mm团聚体中最高，但无定形氧化铝(Alo)在5-10 mm团聚体中最高；非生物因素（铁/铝氧化物、粘粒含量）在稳定<0.25 mm团聚体稳定性中发挥更加重要的作用；而非生物因素和生物因素在稳定较大团聚体（0.25-2、2-5、5-10和10-15 mm）中均发挥作用；有机-矿物复合物对团聚体稳定中发挥着重要作用，尤其是对大团聚体来说这种作用更明显。向第四纪红粘土发育红壤中添加赤铁矿和针铁矿能显著降低降雨溅蚀量，且降低幅度总体呈现随氧化铁添加量增加而增加。0%和0.5%氧化铁添加量下红壤溅蚀量间没有显著性差异。添加比例为4%时，不同氧化铁添加的红壤溅蚀量间差异显著。研究结果有助于深化对红壤降雨溅蚀过程及其机制的理解，为红壤地区的土壤退化防治、水土保持等提供理论指导。在本项目的资助下共发表学术论文4篇，其中SCI2篇；EI1篇，CSCD1篇；接收CSCD论文1篇。