摘要
以神木六道沟小流域为例,分析10座小型淤地坝年淤积沙量、产沙地层出露分布及其土壤粒径,基于"侵蚀-沉积"相关原理和粒径对比分析,探讨了近20年来该流域坡-沟侵蚀关系的演变方向及程度。结果表明:1992到2010年,该流域侵蚀模数由150t/(hm2·a)减少到31.01t/(hm2·a),减少幅度达80%。马兰黄土、离石黄土等各侵蚀产沙地层的侵蚀模数均大幅下降约80%。近20年前后,流域坡面和沟道侵蚀量分别由78.70,298.25t/(hm2·a)减至21.23,50.74t/(hm2·a)。坡-沟侵蚀量相对比例由3.5∶6.5改变为4.6∶5.4。植被改善显著削弱了流域坡面的土壤侵蚀以及径流下沟对沟道侵蚀的增沙效应。
The investigations had been taken to map the outcrop soil stratums distribution in 1992. Surface soil samples were collected on all of outcrop soil stratums and the sediment was collected in the warping dam land in 1992. In 2010, the same field work was taken. Laboratory analyses included basic soil/sediment physical properties, all by standard methods. The sediment resource was identified with equivalent soil- particle size model. The model results indicated that, from 1992 to 2010, under Grain for Green project, the erosion modulus of this watershed reduced from 150 t/（hm~ ~ a） to 31.01 t/（hm2 - a）, the reducing rate was up to 80o/00. The erosion modulus of old loess（Lz）, new loess（L1 ） and sand（S） decreased up to 800//oo. The erosion modulus of slope and gully reduced from 78. ？0 t/（hm2 ~ a） and 298.25 t/（hm2 ~ a） in 1992 to 21.23 t/（hm2 ~ a） and 50. 74 t/（hm2 ~ a） in 2010, and the ratio of slope erosion and gully erosion turned from 3.5 = 6.5 to 4. 6 = 5. 4. Corresponding to the regularly recovering vegetation, this ratio would keep an increasing trend. These significant changes supported the positive ecological benefits of grain for Green project in the water-wind erosion crisscros~ re,finn
出处
《水土保持学报》
CSCD
北大核心
2013年第4期83-87,185,共6页
Journal of Soil and Water Conservation
基金
国家自然科学基金项目(41101265,41230852)
中国科学院知识创新项目(KZCX2-XB3-13,KZZD-EW-04-03-03)
关键词
侵蚀量
坡-沟侵蚀比例
粒径对比分析
产沙地层
小流域
水蚀风蚀交错区
erosion amount
relationship of slope and gully erosion
equivalent soil-particle-size model^outcrop soil stratums~ small watershed~ water-wind erosion crisscross region
