小浪底库区坡地不同利用方式入渗规律与产流产沙特征研究

坡耕地水土流失已成为小浪底库区生态环境和农业可持续性发展所面临的一个重大问题。通过饱和入渗和模拟降雨试验,对不同退耕利用方式(撂荒坡地、造林幼林地、林草间作、农林间作)和传统坡耕地利用方式(坡耕地翻耕休闲、坡耕地翻耕后种植玉米)入渗规律与产流、产沙特征做了研究。结果表明:(1)退耕后坡面饱和入渗率均高于传统方式,其四种方式平均饱和入渗率是传统利用方式的1.48倍;撂荒坡地的饱和入渗率最高;同一坡面,坡底饱和入渗率高于坡中、上部。(2)初始产流时间,撂荒坡地、造林幼林地、林草间作、农林间作分别比翻耕种玉米延迟26.16min、14.89min、13.48min、6.01min,两种传统方式差别不大。持续产流时间退耕方式也长于传统方式。(3)传统方式径流总量是上述四种退耕方式的2~5倍,平均产流速率明显高于退耕方式;产沙总量是退耕方式的3~50倍左右,平均产沙速度是其的1.72~9.4倍;产沙、产流总量和与产流降雨历时密切相关。

Infiltration Law and Runoff-sediment-yielding Characteristics in Different Land Use of Slope Land in the Xiaolangdi Reservoir Area

Water loss and soil erosion have been a serious problem and also a key point to the environment and agriculture sustainable development in the Xiaolangdi Reservoir Area.Infiltration law and runoff-sediment-generation characteristics in different land use types on slope land under Saturated soil permeability and simulated rainfall conditions were investigated.The results showed that(1) the average saturated soil permeability of four slope land use types(being wild,afforestation seedling,intercrop between agriculture and forestry,intercrop between forest and grass) was higher than that of cropland and the saturated soil permeability was increased by 1.8 times to that of cropland.The saturated soil permeability of bottom was the highest in the same slope land.(2)The runoff on being wild,afforestation seedling,intercrop between agriculture and forestry,intercrop between forest and grass started was postponed by 26.16 min,14.89min,13.48min,6.01min,respectively compared with that on corn planted land.And(3)Compared with cropland conversion program,the accumulated runoff volume and the sediment-yielding amount in the runoff increased by 2 and 5 times,respectively.The average runoff-generation was much higher than that of cropland conversion program,too.The accumulated runoff volume and sediment-yielding amount of runoff was significantly related to runoff-yielding rainfall time.