The C factor in Universal Soil loss Equation reflecting the effect of vegetation on soil erosion by water is one of the important parameters for estimating soil erosion rate and selecting appropriate land use patterns. In this study, the C factor for nine types of grassland and woodland was estimated from 195 plot-year observation data of six groups of soil erosion experiments on Loess Plateau. The result indicates that the effects of woodland and grassland on soil erosion keep approximately uniform after two or three years’ growth. The estimated woodland C factor ranges from 0.004 to 0.164, and the grassland C factor ranges from 0.071 to 0.377, showing that the effect of woodland and grassland on soil conservation is greatly better than that of cropland. The study results can be used to compare or estimate the soil loss from land with different vegetation cover, and are the useful references for land use pattern selection and the project of returning cropland to forest or grassland.
不同植被类型对土壤水蚀的影响
张 岩 刘宝元 张清春 谢 云
（1 . 北京师范大学资源科学研究所，北京师范大学环境演变与自然灾害教育部重点实验室，北京 1 0 0 8 7 5；2.国土资源部土地整理中心国土整治研究室，北京 100035）
摘要： 不同植被类型对土壤水蚀的影响因子是计算土壤水蚀速率以及选择适当土地利用方式的基本参数。本文以土壤侵蚀模型中的植被因子（C因子）为指标，研究不同植被类型对土壤水蚀的影响。根据6个水土保持试验项目33个小区共195个小区年的资料，计算了刺槐、柠条、沙棘、沙棘-杨树，沙棘-油松、沙打旺、红豆草、苜蓿和草木樨等9种林草植被因子值。林地植被因子介于0.004到0.164之间，以刺槐林的C值最低。草地植被因子介于0.071到0.377之间，以第一年的草木樨C值为最高。定量对比说明林草植被的水土保持效益明显优于农作物。本项研究结果可以用于定量比较不同植被类型覆盖下的土壤流失速率，对于北方农牧交错带退耕还林还草政策的实施具有参考价值。
关键词： 土壤水蚀；植被因子(C因子)；林地；草地；农作物
通讯作者。E-mail:<zhangyan628@sina.com> 。
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