六盘山叠叠沟小流域土壤稳渗速率及其影响因子

Final Soil Infiltration Rate and Its Influencing Factors in the Small Catchment of Diediegou,Liupan Mountains

采用小区漫流法研究叠叠沟小流域内4种典型植被下的土壤稳渗速率及其影响因子。结果表明:不同植被类型的土壤稳渗速率平均值表现为天然草地>虎榛子灌丛>沙棘灌丛>华北落叶松林地。坡向影响土壤稳渗速率表现为阴坡>半阴坡>阳坡,坡位对土壤稳渗速率的影响表现为中坡位>下坡位>上坡位,坡度对土壤稳渗速率的影响表现为中坡>陡坡>缓坡,当坡度小于25°时土壤稳渗速率随坡度增大而增大,当坡度大于25°时土壤稳渗速率随坡度增大而减小。因此,以坡度25°为分界点,找到了影响土壤稳渗速率的主导因子,并经多元逐步回归得到土壤稳渗速率与主要影响因素的分段函数。

By using a method of overflowing in a slope plot, a final infiltration rate on hillslopes under 4 typical vegetation forms and the influencing factors were investigated in the small watershed of Diediegou. The result showed that the final infiltration rate of different vegetation types were： natural grassland 〉 shrub of Ostryyopsis davidiana 〉 shrub of Hippophae rhamnoides 〉 plantation of Larix principis-rupprechtii. The final soil infiltration rate on different slope aspects showed shady slope 〉 semi-shady slope 〉 semi-sunny slope. The final soil infiltration rate under different slope position exhibited midst slope position 〉 lower slope position 〉 upper slope position. The final soil infiltration rate under different slope gradient showed middle slope gradient 〉 steep slope 〉 gentle slope. The final infiltration rate increased with rising slope gradient as the slope gradient is smaller than 25°, and decreases with slope gradient as it is higher than 25°. Based on the data, the dominant influencing factors were discovered, and the relations between infiltration rate and influencing factors were obtained by step-wise regressing analyses for the cases below or above the slope gradient to 25°.