川中紫色土区农作型小流域水土保持措施设计策略及减蚀效益

水土保持措施设计策略影响到水土流失调控的效益。以“长治”工程农作型小流域为研究对象，采用偏最小二乘等建模方法，分析小流域不同水土保持措施的设计策略和不同措施单位面积的减蚀量和减蚀比，进而对小流域治理措施面积设计策略提出建议。研究表明：①小流域治理面积主要取决于小流域水土流失面积，占后者的90．4％，其他治理措施面积主要取决于治理面积，占水土流失治理面积的8％-31．9％，但是封禁治理面积除外，其面积主要受灌幼林地和荒草地面积影响；②坡改梯、水土保持林、经果林、封禁治理、保土耕作措施的单位面积减蚀量分别为：2430t／km^2·a、4275t／km^2·a、3994t／km^2·a、3614t／km^2·a、2191t／km^2·a，减蚀比分别为8．4％、30．3％、24．8％、22．7％、13．8％，水土保持林的减蚀效益最大；③根据对治理后侵蚀模数大于1000t／km^2·a的小流域治理措施分析，提出1种改进策略，即确保该类小流域的水土保持林造林面积比例高于治理措施总面积的24％，相应地减小坡改梯面积，根据模型计算结果，减蚀效益有明显改善。表1，参18。

Design Strategies and Soft Erosion Reduction Effect of Soft and Water Conservation Measures in Hilly Area of Central Sichuan Basin

Soil and water conservation (SWC) strategy is one of the most important issues for soil erosion control.Designing strategies and soft erosion reduction effect (SERE) of SWC measures are modeled for fanning-type small watershed of "Changzhi project".Tbe results show that:controlling measures mainly depend on the controlling area,taking up 8% - 31.9% of the latter. But enclosed area was mainly affected by low-building cash forest, closing hillside for erosion control, conservation tillage reached 2430 t/km2a, 4275 t/km2 a, 3994 t/km2 a,BWSCF ratio should be higher than 24% for the study watershed.