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以仙鱼小流域为例,通过对各项措施图斑的平均坡度、坡长、保土措施、植被覆盖度、土地利用方式等调查,采用USLE方程的各参数因子,计算土壤流失减少比例.仙鱼小流域通过治理后,水土流失减少比例为28.19%,水土流失防治达到目标要求;通过对不同措施图斑水土流失减少比例分析,水土流失减少比例随着坡度或坡长的增加而增加,以25°坡度、70 m坡长作为变化的分界点,当坡度在25°以下或坡长小于70 m时土壤流失减少比例变化趋势较缓,当坡度在25°以上或坡长大于70 m时土壤流失减少比例增长趋势较快;各项水土保持措施中,以石坎坡改梯防治水土流失的效果最好,坡面水系工程措施可有效提高坡耕地抵御季节性干旱的能力.该研究结果可为今后开展小流域综合治理提供实践经验.
Taking the Xianyu small watershed as an example, through the investigation of the average gradient, slope length, soil conservation measures, vegetation coverage and land use patterns of each measure plot, the reduction proportion of soil loss was calculated by using the parameters of USLE equation. After the treatment of Xianyu small watershed, the proportion of soil erosion decreased by 28.19%, and the prevention and control of soil erosion met the target requirements. Through the analysis of the reduction proportion of soil erosion in the plan areas, the decrease proportion of soil erosion increased with the increase of slope or slope length, Taking 25 ° slope and 70 m slope length as the changing demarcation point, when the slope is less than 25 ° or the slope length is less than 70 m, the trend of decrease of soil loss tends slowly. When the slope is more than 25 ° or the slope length is more than 70 m The trend of decreasing proportion of soil loss tends to increase rapidly. Among all water and soil conservation measures, the effect of stepping on slope with steep slope to control soil and water loss is the best, and the slope water system engineering measures can effectively improve the ability of slope farmland to resist seasonal drought. Provide practical experience for the future comprehensive management of small watershed.