双环直径对土壤入渗速率的影响

Effects of Double-ring Diameter on Soil Infiltration Rate

双环法是测定土壤入渗速率最为广泛最为经典的方法,但双环直径可能影响土壤入渗速率测定结果,因其为地表积水有压入渗,在坡地上测定时,因整平地表时会产生很大扰动,从而产生测定误差。研究设计5组不同直径的双环入渗试验,分析双环直径对土壤初始入渗速率、稳定入渗速率、累计入渗量的影响。结果表明:当双环内环直径分别为15,20,25,30cm时,初始入渗速率分别是常规内环直径为35cm双环的88.3%,110.8%,119.9%,100.7%,稳定入渗率分别是54%,73%,85%,89%。对不同时刻入渗速率进行T值检验发现,用内环直径为20,25,30cm双环测定的入渗过程与常用内径为35cm的双环测定土壤入渗过程无显著差异。考虑地表扰动因素、试验需水量等多因素的影响,可用内环直径20cm、外环直径为35cm的双环替代目前常规内环直径为35cm,外环直径为50cm的双环,用于坡地土壤入渗速率测定,可以减少地表扰动,从而准确测定土壤入渗率,又能节约用水量。

The double-ring infiltration is widely used for measuring soil infiltration rates, and the diameter of double-ring maybe have effect on soil infiltration rates. There will be an error in measurement result because the double-ring infiltration is pressure infiltration which disturbs the land surface when leveling off the surface in the slope land. The initial infiltration rate, saturated infiltration rate and the cumulative infiltra- tion volume were studied using designing five double-ring experiments. The initial infiltration rates of the 15, 20, 25, 30 cm diameter inner rings were about 88.3%, 110.8%, 119.9%, 100.7% of the 35 cm diame- ter ring. Saturated infiltration rates were 54%, 73%, 85%, 89%respectively. Based on the results of soil infiltration rate of T-test among five double-ring experiments, there had no significant difference in the infil- tration process between the 20, 25, 30 cm diameter inner rings and the widely used 35 cm diameter ring. Considering the disturbance on land surface and water demand, the double-ring with diameters of 35 cm and 50 cm for inner and outer rings could be replaced by the double-ring with diameters of 20 cm and 35 cm for inner and outer rings for measuring the soil infiltration, which could decrease the surface disturbance to improve the accuracy of measurement and the water consumption.