典型喀斯特石漠化地区降雨产流产沙特征

Characteristics of rainfall runoff and sediment yield in typical Karst rocky desertification area

为分析喀斯特石漠化地区降雨对水土流失的影响,以贵州省关岭-花江石漠化治理示范区2018年雨季17次侵蚀性降雨的产流产沙数据为例,对水土流失监测径流小区的次降雨特征、降雨产流产沙特征及两者相关性进行分析。结果表明:研究区不同土地利用方式坡面次降雨径流系数平均值为0. 175,降雨大部分入渗。不同径流小区降雨产流产沙存在显著差异,5块样地产流大小为柚木(Tectona grandis)地>火龙果(Hylocereus undulatus Britt)地>裸地>花椒(Zanthoxylum bungeanum Maxim)地>荒草地,产沙大小为柚木地>火龙果地>裸地>荒草地>花椒地。植被覆盖度、土壤厚度对坡面降雨产流、产沙均影响较大,土地利用方式及植被类型对坡面降雨产沙影响次之,对降雨产流影响较小。对径流小区的次降雨径流深、次降雨产沙模数及描述次降雨特征的各指标进行相关性分析,降雨产流与次降雨量之间相关性最好,5块样地平均相关系数为0. 864;降雨产沙与降雨总动能之间相关性最好,5块样地平均相关系数为0. 785。

In order to analyze the impact of rainfall on soil erosion in karst stony desertification area,this paper takes the data of runoff and sediment yield of 17 erosive rainfalls in the 2018 rainy season of Guanling-Huajiang stony desertification control demonstration zone in Guizhou province as an example.We analyzed the characteristics of rainfall,rainfall-runoff and rainfall-sediment in the runoff plot experiment,then we also analyzed the correlation between the latter two. The results are as follows: The average rainfall-runoff coefficient in different land utilization types of the study area was 0. 175. There are significant differences in rainfall-runoff and rainfall-sediment yield in different runoff plots. The amount of rainfall-runoff in five plots are Tectona grandis > Hylocereus undulatus Britt > bare land > Zanthoxylum bungeanum Maxim > unused grassland. The amount of rainfall-sediment yield is Tectona grandis >Hylocereus undulatus Britt > bare land > unused grassland > Zanthoxylum bungeanum Maxim. Vegetation coverage and soil thickness have a great impact on rainfall-runoff and rainfall-sediment yield. The impact of vegetation types and land utilization types on sediment yield is slightly less than vegetation coverage and soil thickness,and the impact on rainfall-runoff is less. Correlation analysis was carried out for each index,and the correlation between rainfall-runoff and rainfall was the best,the average correlation coefficient of the five plots was 0. 864. The correlation between rainfall-sediment yield and rainfall kinetic energy is the best. The average correlation coefficient of the five plots is 0. 785. Our research results can provide reference for vegetation restoration and reconstruction and soil erosion prevention in karst rocky desertification areas.