跨区域量化比较3种土壤类型坡面的拦蓄径流能力

Quantitative Comparison of Runoff Retention Capacity for Hillslopes with Three Soil Types Across Regions

[目的]基于定量化数值建立一个跨区域评价不同土壤类型和管理措施坡面拦蓄径流能力的指标体系,为水土流失防治工作提供科学指导。[方法]在新疆维吾尔自治区伊宁市北山坡的灰钙土、棕红土坡面和贵州赤水市大石河小流域的紫色土坡面各布设了4种管理措施的径流小区,基于2019—2021年4—9月的自然降雨量和径流量观测数据,用径流系数、径流曲线数(CN值)和降雨产流阈值数据量化比较了12个径流小区的减流能力。[结果]不同土壤拦蓄径流能力排序为:灰钙土<棕红土<紫色土,其CN值分别为90.05,89.53和77.36;其降雨产流阈值分别为3.44,3.50和14.96 mm。不同评价指标结果均显示,灰钙土和棕红土管理措施坡面的拦蓄径流能力顺序为:枯草覆盖>水平沟>增渗孔>对照;紫色土管理措施坡面减流能力的顺序为:园地>草地>耕地>对照。对于对照小区,当径流系数增加1%时,灰钙土、棕红土和紫色土的径流深分别增加了1.73,2.61和6.79 mm;当CN值增加1时,3种土壤坡面的径流深则将分别减少1.00,1.00和0.71 mm。[结论]跨区域评价不同土壤类型坡面的减流能力时,推荐用CN值和降雨产流阈值指标,不宜使用径流系数。

[Objective]A cross-regional index system was established based on quantitative values to evaluate the runoff retention capacity for slopes of different soil types managed under different practices in order to provide scientific guidance for the prevention and control of soil erosion.[Methods]Runoff plots with four kinds of management measures were set up on a gray calcium soil slope and a brown red soil slope of the northern slope of Yining City,Xinjiang Wei Autonomous Region,and on a purple soil slope of Dashi River basin,Chishui City,Guizhou Province.Based on observed natural rainfall and runoff data from April to September in 2019 to 2021,runoff coefficient,runoff curve number(CN value),and rainfall-runoff production threshold data were used to quantitatively compare the runoff reduction capacity of 12 runoff plots.[Results]The runoff retention capacity of different soils followed the order of gray calcium soil<brown red soil<purple soil,and the CN values were 90.05,89.53 and 77.36,respectively.The rainfall-runoff production thresholds were 3.44,3.50,and 14.96 mm,respectively.The results of different evaluation indexes showed that runoff retention capacity of gray calcium soil and brown red soil management measures followed the order of dry grass cover>horizontal ditch>seepage hole>control.Slope flow reduction ability of the purple soil management measures followed the order of garden land>grassland>cultivated land>control.When the runoff coefficient for the control plot increased by 1%,the runoff depth of gray calcium soil,brown-red soil,and purple soil increased by 1.73,2.61,and 6.79 mm,respectively.When the CN value was increased by 1,the runoff depth of the three soil slopes decreased by 1.00,1.00,and 0.71 mm,respectively.[Conclusion]When evaluating runoff reduction capacity of slopes of different soil types across regions,it is recommended to use CN value and rainfall-runoff production threshold,but not runoff coefficient.