紫色土区植物篱根-土复合体抗侵蚀性对微地形变化的响应机理

Soil erosion and water loss of sloping farmlands in the purple soil area was very serious, and it had restricted the local social and economic development and ecological civilization construction. Hedgerow was a very efficient measure in controlling sloping farmlands’ soil erosion and water loss in the worldwide. It had ideal ecological, economic and social benefits. Currently there were too many hedgerows in the purple soil area, so as studies about hedgerow. Almost all studies concerned hedgerow’s effects on external environment, but so little about external environment’s effects on hedgerow. Especially studies of micro-topographical changes’ effects on hedgerow root-soil composite’s anti-erodibility was few. Aiming at this problem, the project planed to selected many hedgerow sloping farmlands with different micro-topographies in the purple soil area to do intensive studies. The properties of hedgerow roots and root-zone soil were the starting point of this study, and technologies of digital photogrammetry, WinRHIZO root analysis system and so on would be used to quantify the effects of micro-topographical Changes on hedgerow root-soil composite’s anti-erodibility/root mechanics properties/root-zone soil anti-erodibility. Sensitive parameters in affecting hedgerow root-soil composite’s anti-erodibility would be screened out, and the mechanism of composite’s anti-erodibility responding to micro-topographical changes would be revealed. Results of this study can provide scientific basis for hedgerow popularization, application and management, and ecological management in sloping farmlands.

紫色土区坡耕地严重的水土流失制约着该区经济发展、社会进步和生态文明建设。植物篱是治理坡耕地水土流失的一项有效措施，具有良好的生态、经济和社会效益，在紫色土区具有广泛应用。但植物篱已有的研究多关注的是植物篱对外界环境的影响，而较少关注因外界环境的改变诱发的植物篱的响应，尤其是地下根-土复合体抗侵蚀性对微地形变化的响应的研究颇少。本项目针对此不足，拟在紫色土区野外选取具有不同微地形的植物篱坡耕地，从植物篱根系和根区土壤特性出发，采用数码摄影测量、WinRHIZO根系扫描分析等方法，量化坡耕地微地形变化对植物篱根-土复合体抗侵蚀性/根系力学性能/根区土壤抗蚀性的影响，筛选出影响植物篱根-土复合体抗侵蚀性的敏感性参数，阐明紫色土区坡梯演变过程中植物篱根-土复合体抗侵蚀性对微地形变化的响应机理。研究结果可为植物篱技术的推广应用和科学管理，以及坡耕地水土流失生态治理提供科学依据。

植物篱是治理坡耕地水土流失的一项有效措施，具有良好的生态、经济和社会效益，在紫色土区具有广泛应用。但植物篱已有的研究多关注的是植物篱对外界环境的影响，而较少关注因外界环境的改变诱发的植物篱的响应，尤其是地下根-土复合体抗侵蚀性对微地形变化的响应的研究颇少。本项目针对此不足，在四川遂宁水土保持试验站选取多个植物篱小区，采用WinRHIZO根系扫描分析等方法，量化微地形变化对植物篱根-土复合体抗侵蚀性/根系力学性能/根区土壤抗蚀性的影响，筛选出影响植物篱根-土复合体抗侵蚀性的敏感性参数，阐明紫色土区坡梯演变过程中植物篱根-土复合体抗侵蚀性对微地形变化的响应机理。结果表明：（1）同一篱带，篱前淤积带土壤保水贮水能力优于篱下土坎，其中篱前淤积带土壤自然含水率较之篱下土坎显著高6.52%~12.13%。（2）同一篱带，篱下土坎土壤透气性以及土壤抗剪性能均优于篱前淤积带，其中篱下土坎土壤非毛管孔隙度较之篱前淤积带显著高5.61%~57.70%。（3）同一小区，篱前淤积带保水贮水能力均表现为下坡>中坡>上坡，而篱下土坎均为上坡>中坡，其中15°香根草植物篱小区的趋势最明显。（4）同一小区，篱前淤积带土壤内摩擦角、粘聚力和抗剪强度均表现为上坡>中坡>下坡，篱下土坎均为上坡>中坡，其中10°香根草植物篱小区的趋势最明显。（5）雨季前后篱前淤积带和篱下土坎土壤透气性、保水贮水能力及抗剪性能均无显著变化。（6）同一坡度下，香根草植物篱较新银合欢植物篱更有利于篱前淤积带土壤团聚体结构稳定性的增强。研究结果可为植物篱技术的推广应用和科学管理，以及坡耕地水土流失生态治理提供科学依据。