土石混合紫色土坡面水文过程的实验研究

Effects of Rock Fragment Cover on Hydrological Processes in Purple Soils

土壤中的碎石改变了均质土壤的容重、孔隙度与孔径分布等物理性质,从而对土壤水文与侵蚀过程造成影响。该研究在室内人工模拟降雨条件下,对6种不同碎石体积含量(0,5%,10%,20%,30%,40%)紫色土坡面的水文过程进行了模拟。结果表明,径流系数与碎石含量之间差异显著(F=115,P<0.01)且呈显著正相关关系;土壤湿润锋随着碎石含量的增大呈增加的趋势;不同碎石含量的土壤坡面起始产流时间差异显著(F=208,P<0.01),且产流时间随碎石含量的增加而减小;碎石含量为20%时,土壤平均产流量最高,超过20%时,产流量反而降低;但碎石含量对径流流速没有显著影响。该研究结果可以为碎石含量在紫色土中的作用机理提供理论基础,同时为紫色土区土壤资源的合理利用提供科学依据。

Variable rock fragments in purple soil change some of the physical properties of homogeneous soil and therefore their influence is significant on the hydrological and erosional processes in purple soil regions.Considerable attention is being paid to quantitative information of the effects of rock fragment cover on soil infiltration,runoff and erosion. This research investigated six purple soil samples from a hillslope area with different rock fragment contents ranging from 0 to 5%,10%,20%,30%,and 40%. The results showed that the runoff coefficient and initial runoff rate were significantly influenced by the rock fragment content. As the rock fragment increased,the runoff coefficient（ F = 115,P 0. 01） and wetting front increased while the surface runoff rate decreased significantly（ F = 208,P 0. 01）. The average runoff rate reached its highest value with a rock fragment content of 20% and declined when rock fragment content was more than 20%. Rock fragment content had no significant effect on runoff flow velocity. The results of this research can provide empirical a case study for further exploring the mechanism of rock fragment content in purple soils and its effect on hydrological processes. Findings can also be helpful for rational utilization of soil resources and improving soil erosion models in purple soil regions.