模拟降雨对亚热带阔叶林土壤坡面产沙产流及养分流失的影响

发布时间：2019-01-20 14:23

【摘要】：采用人工降雨方法,研究了不同降雨强度和坡度对亚热带阔叶林土壤坡面产沙产流及养分流失的影响。结果表明:(1)在不同降雨强度下,初始产流时间随坡度的增加趋于提前,随降雨强度的增大产流时间提前,降雨强度对初始产流时间的影响大于坡度变化的影响。(2)在同一坡度条件下,产流强度和平均入渗强度随降雨强度的增加而增加;曲线拟合的结果表明产流强度随时间遵循幂函数变化规律,而坡面入渗强度随时间呈对数函数变化。(3)不同降雨强度下,径流量随降雨历时的变化趋势基本一致,径流量均随降雨历时呈"增加—稳定"趋势,在整个降雨过程中,径流量随坡度的增加而增加,相同坡度下,径流量随着降雨量的增加而增加;降雨初始时刻,坡度对径流量的影响较小,而在降雨后期,降雨强度和坡度对径流量的影响较大;产流率与径流量的变化趋势相反,随降雨历时呈"降低—稳定"趋势,在整个降雨过程中,土壤产流率随坡度的增加而降低,在相同坡度下,产流率随着降雨量的增加而增加。(4)侵蚀泥沙量的变化特征表现为坡度越大,坡面侵蚀泥沙的流失量越大;泥沙侵蚀量随降雨历时的增加而增加,在降雨10min左右达到峰值;在相同坡度和降雨历时下,泥沙侵蚀量随降雨强度的增加而增加;不同坡度下的侵蚀泥沙量在峰值前后与产流历时均呈乘幕函数变化,不同坡度下侵蚀泥沙养分含量与产流历时间的关系均可用幂函数表达。(5)不同坡度条件下,泥沙量与侵蚀泥沙中养分的含量均存在不同程度的正相关关系,其中坡度为15°,20°和25°时,侵蚀泥沙养分含量与泥沙流失量间的相关性明显优于坡度为5°和10°时,说明侵蚀泥沙量的增加会引起泥沙中各类养分含量的增加效应,而不同坡度下的全磷与侵蚀量没有显著的相关关系(P0.05)。
[Abstract]:The effects of different rainfall intensity and slope on sediment yield and nutrient loss in subtropical broadleaved forest were studied by artificial rainfall method. The results are as follows: (1) under different rainfall intensity, the initial runoff yield time tends to advance with the increase of slope, and the runoff generation time increases with the increase of rainfall intensity. The effect of rainfall intensity on the initial runoff yield time is greater than that on the slope change. (2) under the same slope condition, the runoff yield intensity and the average infiltration intensity increase with the increase of rainfall intensity. The curve fitting results show that the runoff yield intensity follows the law of power function with time, while the infiltration intensity of slope surface changes with time logarithmic function. (3) under different rainfall intensity, the variation trend of runoff with rainfall duration is basically the same. In the whole rainfall process, the runoff increased with the increase of the slope, and the runoff increased with the increase of rainfall at the same slope. At the beginning of rainfall, the effect of slope on runoff is small, but in the later stage of rainfall, the influence of rainfall intensity and slope on runoff is greater. The trend of runoff yield is opposite to that of runoff. With the duration of rainfall, the runoff yield of soil decreases with the increase of slope, and with the same slope, the runoff yield of soil decreases with the increase of slope. The runoff yield increases with the increase of rainfall. (4) the change characteristic of erosion sediment quantity is that the bigger the slope is, the larger the erosion sediment loss is; The amount of sediment erosion increases with the increase of rainfall duration, and reaches the peak value at the 10min of rainfall, and increases with the increase of rainfall intensity under the same slope and duration. Under different slopes, the amount of erosion sediment varies with the peak value and the duration of runoff, and the relationship between the nutrient content of erosion sediment and the time of runoff under different slopes can be expressed by power function. (5) under different slope conditions, the relationship between the nutrient content of eroded sediment and the time of runoff yield can be expressed by power function. There was a positive correlation between sediment content and nutrient content in eroded sediment. When the slope was 15 掳, 20 掳and 25 掳, the correlation between sediment nutrient content and sediment loss was better than that in 5 掳and 10 掳slope. The results showed that the increase of sediment amount would cause the increase of nutrient content in sediment, but there was no significant correlation between total phosphorus and erosion at different slopes (P0.05).
【作者单位】：长沙理工大学水利工程学院;湖南国地水利水电设计咨询有限公司;中国科学院亚热带农业生态研究所亚热带农业生态过程重点实验室;
【基金】：湖南省水利厅创新课题项目(ASX-2014011) 湖南省科技厅课题项目(2014-0306)
【分类号】：S714.7

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