低山丘陵区水土保持治理与生态环境效应

分析了低山丘陵区水土流失等级分布，水土流失的形成原因及危害，指出低山丘陵区水土流失综合治理要以小流域综合治理为主，阐明小流域水土流失的规律性，以及根据小流域3个地貌单元类型按“三条带”模式进行综合治理：山顶林草防治、山腰经济林带整治、山脚坡改梯治理的技术措施，着重论述综合治理的生态环境效应：明显地保水保土保肥，在降雨量相同的情况下等高种植、坡改梯、封山育林雨强明显小于坡耕地，起始产流时间延迟，径流量减少近2/3，土壤侵蚀量明显比坡耕地少得多。土壤侵蚀携带养分，坡耕地损失量最大，等高种植全氮、全磷的损失量最小；坡改梯有机质、有效氮、速效钾流失量较少，说明坡改梯的保肥效果优于等高种植。林草植被对改善生态系统的环境效应和提高生物多样性功能，为低山丘陵区生态环境恢复和农业可持发展奠定基础。

WATER AND SOIL CONSERVATION AND MANAGEMENT WITH THE ECOLOGICAL ENVIRONMENT EFFECT IN THE DISTRICT OF LOW MOUNTAINS--TAKING XUYI COUNTY OF JIANGSU PROVINCE AS AN EXAMPLE

This text analyses the reasons and danger of soil erosion in the district of low mountains and hills,and points out that the comprehensive administration of soil erosion of low mountains and hills district should rely mainly on small basin comprehensive administration. The regularity of small basin soil \{erosion\} and the mode for comprehensive administration are explained according to small basin three ground form unit type,that is,wood-grass is prevented on the mountain top;economic forest belt is renovated on the hill-side;technological measure that slope is changed to ladder manages on the hill-foot.The paper describes the ecological environment effect of comprehensive administration. When the soil is corroded,it carries the nutrient,with the losing amount of the cultivated land being the biggest and the losing amount of all N and P of the same high planting the least. The losing amount of organic matter,effective nitrogen and quick-acting potassium of changeing slope to the ladder is better. It is proved that to protect fertile result of changing the slope to the ladder is better than the same high planting. The wood-grass vegetation improves the environment and raises the bio-diversity function of ecosystem. This text will resume and establish the foundation for ecological environment recovery and sustainable agricultural development in the district of low mountains and hills.