含水量、坡度和流量对土壤分离能力的影响

土壤分离过程为侵蚀产沙提供了物质准备,对其发生、发展的过程进行准确模拟具有重要的实践和理论意义。选取棕壤为研究对象,设计6个土壤含水量(3%,6%,9%,12%,15%,18%)、3个坡度(5°,10°,15°)和3个流量(8,12,16L/min),分析含水量、坡度和流量对土壤分离能力的影响。结果表明:(1)土壤分离能力均随含水量的增大呈下降趋势,且土壤分离能力间的差异随含水量的增大而减小,当含水量18%时,土壤分离能力几乎为0。土壤分离能力与含水量呈现二次多项式关系,在含水量3%时,土壤分离能力最高。(2)土壤分离能力在含水量6%,9%,12%,18%时均随坡度的增大而增大,并且与坡度呈二次多项式关系,在坡度15°时,土壤分离能力达到最大。(3)土壤分离能力在含水量3%~12%均随流量的增大而增大,并且与流量呈二次多项式关系,流量为16L/min时,土壤分离能力最大。(4)仅考虑两者对土壤分离能力的影响,误差的贡献率均为最高。若考虑三者的影响,坡度对土壤分离能力变异的贡献率最大(29.64%),其次为含水量(22.29%)和流量(19.72%),土壤分离能力的模拟精度分别由0.550,0.638,0.498显著提高到0.995。

Effects of Soil Moisture Content, Slope Gradient and Flow Discharge on Soil Detachment Capacity

Soil detachment process provides material for soil erosion, which is importance for understanding soil erosion process and building soil erosion model. In this study, the Brown soil was selected as the research object. Six soil moisture contents (3%, 6%, 9%, 12%, 15% and 18%), three slope gradients (5°, 10° and 15°), and three flow discharges (8, 12 and 16 L/min) were designed. The effects of soil moisture content, slope gradient and flow discharge on soil detachment capacity were explored. The results showed that: (1) As soil moisture content increased, soil detachment capacity decreased, and the differences of soil detachment capacity decreased; the detachment capacity was almost 0, when soil moisture content was 18%. There was a quadratic polynomial function between soil detachment capacity and soil moisture content, and soil detachment capacity was the highest when soil moisture content was 3%. (2) Soil detachment capacity increased with increasing of slope gradient when soil moisture content were 6%, 9%, 12% and 18%,respectively, and a quadratic polynomial relationship exsited between soil detachment capacity and slope gradient. When the slope gradient was 15°, soil detachment capacity reached the maximum. (3) Soil detachment capacity increased with increasing of flow discharge when soil moisture content was 3%~12%, and had a quadratic polynomial relationship with flow discharge. When flow discharge was 16 L/min, soil detachment capacity had the maximum value. (4) If only considered the influence of two factors, the contribution rate of the error was the largest. With three factors included, the contribution rate of slope gradient to the variation of soil detachment capacity was the largest (29.64%), followed by soil moisture content (22.29%) and flow discharge (19.72%). The simulation accuracy of soil detachment capacity could be increased from 0.550, 0.638 and 0.498 to 0.995 by including soil moisture content, flow discharge and slope gradient.