土质地埂对紫色土坡耕地梯化过程的作用机理

Ridges were the important component of the traditional sloping cultivated lands, especially for the steep sloping cultivated lands. Not only soil and water were intercepted by the ridge, but also the rainfall runoff erosion and tillage erosion were used by the ridge and the terracing process were occurred on the sloping cultivated lands, then the stable terrace land were formed. However, there were less study on the mechanism and function of the terracing process. Taking the sloping cultivated lands with soil ridge of the purple soil as the study object, study on lots of investigation of the cultivated history, combined with artifical ploughing migration experiment and artificial simulated rainfall experiment and used the nuclide tracing technology to clarify the terracing process and mechanism of the sloping cultivated lands with soil ridges. then, analyzed the relationshiop between the soil erosion intensity and slope soil redistribution, terracing velocity, tillage intensity, slope gradient, soil redige height, soil ridge distance to further modelling the terracing velocity and the soil erosion intensity, then testing this model. Final, proposed the reasonal height and distance of the soil ridge on slopoing cultivated lands with different slope gradients in the condition of less soil erosion intensity. This study could offer the theory and data supports on sustained developed of the sloping cultivated lands in the purple soils regions.

地埂是传统坡耕地、特别是陡坡耕地的重要组成部分，不仅具有防治水土流失的作用，而且有效地利用了降雨径流侵蚀和耕作侵蚀，使坡地逐步梯化，形成较稳定坡式梯地，但其梯化过程机理与结构功能的优化研究较少。本项目拟通过大量紫色土土质地埂坡耕地梯化历史的勘察，开展野外大田试验和长期定位监测小区试验，运用人工降雨模拟、耕作侵蚀模拟与核素示踪技术，阐明土质地埂对坡耕地梯化过程的作用与梯化速度，揭示犁耕侵蚀和降雨侵蚀共同作用下地埂对坡耕地的梯化机理；分析坡面土壤侵蚀强度与土壤再分布通量、梯化速度、耕作强度、田面坡度、地埂高度、地埂间距的关系，建立紫色土坡耕地坡面梯化速度和土壤侵蚀强度模型，提出紫色土坡耕地土壤流失量最小条件下的最适宜坡耕地土质地埂高度和地埂间距，为紫色土坡耕地整治和可持续利用提供科学依据和数据支持。

地埂是传统坡耕地、特别是陡坡耕地的重要组成部分，不仅具有防治水土流失的作用.，而且有效地利用了降雨径流侵蚀和耕作侵蚀，使坡地逐步梯化，形成较稳定坡式梯地，.但其梯化过程机理与结构功能的优化研究较少。本项目拟通过大量紫色土土质地埂坡耕地.梯化历史的勘察，开展野外大田试验和长期定位监测小区试验，运用人工降雨模拟、耕作.侵蚀模拟与核素示踪技术，阐明土质地埂对坡耕地梯化过程的作用与梯化速度，揭示犁耕.侵蚀和降雨侵蚀共同作用下地埂对坡耕地的梯化机理；分析坡面土壤侵蚀强度与土壤再分.布通量、梯化速度、耕作强度、田面坡度、地埂高度、地埂间距的关系，建立紫色土坡耕.地坡面梯化速度和土壤侵蚀强度模型，提出紫色土坡耕地土壤流失量最小条件下的最适宜.坡耕地土质地埂高度和地埂间距，为紫色土坡耕地整治和可持续利用提供科学依据和数据.支持。