CSLE模型中水土保持耕作措施因子研究进展

Soil and water conservation tillage measure factor T in the CSLE model:

中国土壤流失方程(Chinese soil loss equation,CSLE)是我国用于定量评价和预测区域土壤侵蚀的重要模型。水土保持耕作措施因子(T)是该模型中的7个关键因子之一,能反映水土保持耕作措施对土壤侵蚀的削减作用,其准确估算对基于CSLE模型的区域土壤侵蚀评价及动态对比分析至关重要。通过文献资料调研,总结目前获取T因子的6种方法,并对比各种方法的优缺点和适用条件。研究表明:水利普查结果查询法和区域水土流失动态监测查询法,获取便捷且应用广泛,但精度有待验证;土地利用类型划分公式法计算简便且适用于流域等大尺度,但受土地利用/覆盖类型解译的限制;径流小区公式法精度较高,适用于小区等小尺度;坡度分级法和水土保持耕作措施赋值法实际应用性强,可用于小流域、区域等尺度,但需考虑空间异质性。

[Background]The Chinese soil loss equation(CSLE)is an important tool for the quantitative evaluation and prediction of regional soil erosion in China.In this model,the soil and water conservation tillage measure factor(T)is one of the seven important factors,which reflects the potential impact of soil and water conservation tillage measures on soil erosion.It is essential to assess the T factor value in an accurate way for the regional soil erosion evaluation and dynamic comparative analysis using the CSLE model.[Methods]Numerous literature retrievals were carried out with“Chinese soil loss equation(CSLE)”and“tillage factors”as keywords,we selected the literatures for analysis and integration.Based on these references,we summarized six methods to obtain the T factor value,and compared the advantages,disadvantages and the applicable conditions of each method.[Results]1)Inquiry Method of Water Conservancy Census Results is extensively used due to its convenience,while the T factor is revised combing with the data of investigation units and runoff plots in the study areas.2)Dynamic Monitoring and Inquiry Method of Regional Soil and Water Loss is simple and easy to proceed,however it is difficult to determine the T value of other crops as it is only for 10 main crops in China.3)Land Use Classification Formula Method is easy to be used,and can be applied at small watershed,watershed and regional scale,but it requires to integrate remote sensing interpretation and query method to generate the specific factor values of various land use types and tillage measures,and it is a cumbersome,high-cost and time-consuming task while used at large scale.4)Runoff Plot Formula Method is the most fundament alway to obtain relatively accurate T factor method;however,it is difficult to compare the effects of different tillage measures on soil erosion,and sediment data in the runoff plots of control and soil and water conservation measures need regular management and long-term monitoring.Runoff,soil erosion and sediment yield vary significantly in different scale basins,thusit is difficult to compare the effects of different tillage practices on soil erosion.5)Slope Classification Method is of strong operability,and it does not rely on standard runoff plot,but accurate extraction of slope is needed.6)Value-Assigned Method of Tillage Measures for Soil and Water Conservation is simple and convenient;while the accuracy and applicability in different research areas are required to be investigated.[Conculsions]These findings are of great significance to the selection of the calculating methods of soil and water conservation tillage measures.Nevertheless,in order to ensure the accuracy of T factor values obtained in the study area,the dynamic monitoring of soil and water loss in runoff plots under different tillage measures should be carried out for a long time in combination with local rotation system.In the large-scale study area,it is necessary to assign the T factor in combination with the national rotation system regionalization,and to calculate the T factor of other tillage measures in the study area via spatial information technology and field investigation.Besides,it is necessary to fully consider the specialty of the study area and the application scope of the selected method.The selection of control plot for tillage measures varies when different researchers calculate T factor value by runoff plot formula method,which leads to the difference of T factor value actually obtained,thus,it needs further exploration.