不同雨强、坡度对秸秆覆盖保持水土效果的影响

发布时间：2019-03-19 20:17

【摘要】：利用室内人工模拟降雨试验,研究了4种设计雨强(33,54,94,125mm/h)、3种设计坡度(5°,10°,25°)在覆盖条件下对紫色土坡面初始产流时间、覆盖保水率和保沙率的影响。结果表明:覆盖条件下初始产流时间相比裸地均有一定的滞后效果,且其初始产流的滞后时间随坡度、雨强的增加而减少。当坡度增大至25°,雨强在94mm/h以上时,其滞后时间逐渐趋于稳定,在1.61~2.84min范围内波动。雨强是影响秸秆覆盖保持水土作用的重要因子,与覆盖保水率、保沙率均在0.01水平上呈显著负相关,且在不同坡度条件下均可以用抛物线进行很好的描述。不同坡度条件下,覆盖的保水率随雨强的增加逐渐下降至14.5%,而其保沙率则只下降至92.25%,相比覆盖的保水作用,其保沙作用更加明显。覆盖条件下,坡度对坡面产流及产沙的贡献率均大于50%,坡度对秸秆覆盖保持水土的作用影响很大。坡度对坡面侵蚀的贡献率在裸地和覆盖条件下均随雨强的增加而呈现减小的趋势,且在相同雨强下,坡度的贡献率在覆盖条件下均大于裸地,在大雨强下(94mm/h和125mm/h)差异明显。
[Abstract]:The effects of four designed rainfall intensities (33, 54, 94125 mm / h) and three designed slopes (5 掳, 10 掳, 25 掳) on the initial yield time, water retention rate and sediment retention rate of purple soil slope under mulching conditions were studied using artificial simulated rainfall experiments in laboratory. The results show that the initial runoff production time under the condition of mulching has a certain lag effect compared with the bare soil, and the lag time of the initial runoff production decreases with the increase of slope and rain intensity. When the slope increases to 25 掳and the rain intensity is above 94mm/h, the lag time tends to stabilize gradually and fluctuates in the range of 1.61~2.84min. Rain intensity is an important factor affecting soil and water conservation by straw mulching, which is negatively correlated with water retention rate and sediment retention rate at 0.01 level, and can be described by parabola under different slope conditions. Under different slope conditions, the water retention rate of mulching decreased to 14.5% with the increase of rain intensity, while the sand retention rate only decreased to 92.25%, which was more obvious than that of mulching. Under the condition of mulching, the contribution rate of slope to runoff yield and sediment yield was more than 50%, and the slope had a great effect on soil and water conservation by straw mulching. The contribution rate of slope to slope erosion decreases with the increase of rain intensity under both bare land and cover conditions, and under the same rainfall intensity, the contribution rate of slope to slope erosion is larger than that of bare land under the same rainfall intensity, and the contribution rate of slope to slope erosion is higher than that of bare land under the same rainfall intensity. The difference was obvious in heavy rain (94mm/h and 125mm/h).
【作者单位】：四川农业大学林学院;
【基金】：国家“十二五”科技支撑计划重大项目“长江上游低山丘陵区生态综合整治技术与示范”(2011BAC09B05) 四川省高校水土保持与荒漠化防治重点实验室建设项目四川农业大学研究生社会实践和科技服务团项目
【分类号】：S157.1

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