伊犁河谷5种土壤管理措施减流减沙效果分析

伊犁河谷区域水力侵蚀等级中等偏强,分析土壤管理措施的减流减沙效果为土地资源的可持续利用和防治水土流失提供参考.本文采用野外人工模拟降雨试验,研究在10、20和36 mm/h 3种降雨强度条件下裸地、角果藜覆盖、木地肤覆盖、鱼鳞坑、水平沟等5种典型土壤管理措施的产流产沙过程,并分析比较不同土壤管理措施的减流减沙效果.结果表明:不同降雨强度下,裸地初始产流时间最短,水平沟未产流;降雨强度是影响产流产沙的关键因素之一,径流速率和含沙量随降雨强度的增大而增大;减流减沙效果由高到低的顺序为:水平沟＞木地肤覆盖＞鱼鳞坑＞角果藜覆盖＞裸地,木地肤覆盖、鱼鳞坑措施减沙效果明显.水平沟、木地肤覆盖措施减流减沙效果较好,可以在该区域防治水土流失中推广应用.

Effects of five soil management measures on runoff and sediment reduction in Ili Valley of Xinjiang

Background]The grade of water erosion is moderately strong in Ili Valley of Xinjiang.This work aims to explore the effects of different soil management measures on runoff and sediment reduction,and to provide sustainable utilization of land resources and effective measurement of soil and water conservation.Methods] Artificial rainfall simulation experiments with 3 rainfall intensities (20 mm/h,10 mm/h and 36 mm/h),5 soil management measures (bare land,Ceratocarpus arenarius L.covered,Kochia prostrate (L.) Schrad.covered,fish scale pit,and horizontal ditch),and totally 15 times of experiments were conducted to analyze runoff and sediment process in the field.Meanwhile,with Excel 2007 and SPSS 19.0,we analyzed the relationship between sediment concentration and runoff rate,and compared the effects of runoff and sediment reduction under different rainfall intensities.Results] The initial runoff time of bare land was so short that suffered rainfall erosion easily,while runoff of horizontal ditch was never happened under 3 artificial rainfall simulations.Although C.arenarius L.covered measure did not produce runoff under 20 mm/h rainfall intensity,there was runoff when the rainfall intensity was 10 mm/h.The reason for this phenomenon was due to higher antecedent soil moisture for the second rain,i.e.,10 mm/h rainfall.The runoff rate and sediment concentration increased as rainfall intensity increased for all experiments.By using linear regression analysis in SPSS 19.0,we found that the relationship between the sediment concentrations and the runoff rates under the measures of bare land,C.arenarius L.covered,K.prostrate (L.) Schrad.covered and fish scale pit were all linearly significant.And we did not obtain the data of horizontal ditch because it was never happened runoff under 3 rainfall intensities.However,the sediment concentration decreased with the increase of the runoff rate under K.prostrate (L.) Schrad.covered measure.Sediment and runoff reduction of all measures listed in the following order:horizontal ditch ＞ K.prostrate (L.) Schrad.covered ＞ fish scale pit ＞ C.arenarius L.covered ＞ bare land.Therefore,the measures of fish scale pit and K.prostrate (L.) Schrad.covered showed more obvious effects on runoff and sediment reduction than the other soil management measures.Conclusions] This study demonstrated that the measures of horizontal ditch and K.prostrate (L.) Schrad.covered effectively reduced runoff rate and sediment concentration in Ili Valley of Xinjiang and should be applied in soil and water conservation in this area.