贵州省黔南区不同侵蚀性雨型条件下生物措施对坡面产流产沙的响应

为探讨不同降雨条件下的生物措施对坡面产流产沙特征的影响,分析了贵州省黔南自治州云雾水土保持监测站2014—2017年4年6个小区104次侵蚀性降雨下的实测产流产沙数据。结果表明：（1）侵蚀性降雨按历时、雨强和雨量可分为3类,包括A雨型（中历时、中雨强、中雨量）,B雨型（长历时、小雨强、大雨量）,C雨型（短历时、大雨强、小雨量）。C雨型为引起区域水土流失的主要雨型。（2）较坡耕地而言,A雨型和C雨型条件下减流量均呈水平阶整地+经果林 > 水保林 > 人工草地 > 自然恢复草地 > 经果林的趋势;减沙量均为水平阶整地+经果林 > 人工草地 > 水保林 > 自然恢复草地 > 经果林。B雨型减流量为水平阶整地+经果林 > 自然恢复草地 > 水保林 > 人工草地 > 经果林;减沙量为水平阶整地+经果林 > 自然恢复草地 > 人工草地 > 水保林 > 经果林。除自然恢复草地外B型雨条件下各措施对水土流失的调控作用不如A雨型和C雨型。不同措施对坡面产沙量的调控作用优于产流量,自然恢复草地在B型雨下具有良好的水土保持效果。（3）坡耕地水土流失最为严重,多年平均土壤侵蚀模数为365.33 t/（km²·a）,水平阶整地+经果林措施水土保持效果最优,其土壤侵蚀模数为3 t/（km²·a）,较坡耕地可降低土壤侵蚀率达99.2%。同时,水平阶整地+经果林措施在A、B、C雨型下较坡耕地可分别减少产流62.7%,53.0%和63.2%。（4）坡面产流同降雨一样,集中在5—8月;C雨型与产沙量集中分布在5—6月。根据研究结果,研究区每年的5—8月为水土流失高发期,尤其是5,6月,这个时段应为水土流失治理的重点时段,在治理同时要针对不同雨型条件采取不同生物治理措施,并且要对C雨型进行重点防范。

Response of Runoff and Sediment Yield to Biological Measures on Slopes Under Different Erosive Rain Patterns in Southern Guizhou

In order to explore the soil and water conservation benefit of different ecological restoration measures on sloping land under different rainfall conditions, this study analyzed the runoff and sediment under six ecological restoration measures (Ecological restoration grassland, ERG; Level terrace and preparation+fruit forest, LF; Fruit forest, FF; Sloping land, SL; Cultivated pastures, CP; Soil and water conservation forest, SWF) under the 104 erosive rainfalls. The observation data from 2014 to 2017 of runoff plots located in the Yunwu Water and soil conservation monitoring station, Guizhou province were used. The results showed that: (1) According to rainfall duration, rainfall intensity and rainfall, erosive rainfall could be divided into three types: A-type (medium duration, medium rainfall intensity and medium rainfall); B-type (long duration, light rainfall intensity and large rainfall); C-type (short duration, heavy rainfall intensity and small rainfall), and C-type was the main cause of regional soil erosion. (2) Compared with sloping farmland, the runoff reduction under the A-type and C-type showed the trend of LF > SWF > CP > ERG > FF, and the sediment reduction showed the trend of LF > CP > SWF > ERG > FF. The runoff reduction under the B-type showed the trend of LF > ERG > SWF > CP > FF, and the sediment reduction showed the trend of LF > ERG > CP > SWF > FF. Except ERG, the control effect of different measures on soil and water loss under A-type and C-type was better than that B-type. The control effect of different measures on slope sediment yield was better than that of runoff. ERG had good soil and water conservation effect under B-type. (3) The soil erosion of sloping land was the most serious. Compared with sloping farmland, the runoff reduction rate of LF was 62.7%, 53.0% and 63.2% under A-type, B-type and C-type respectively. The soil erosion modulus of LF was 3 t/(km²·a), which could reduce the soil erosion rate by 99.2% compared with the sloping farmland. (4) Slope runoff and rainfall were concentrated from May to August. Slope sediment and C-type were concentrated in May and June.