【作者】 曾繁富；

【导师】 赵同谦；

【作者基本信息】 河南理工大学 ， 地质资源与地质工程， 2010， 硕士

【摘要】 选取丹江口水库位于河南部分的最大入库河流老鹳河的支流蒿坪河小流域为研究对象,以修建的5组野外径流场等设施为依托,系统开展了自然降雨条件下不同坡度和土地利用类型非点源污染产生特征的研究。研究结果表明:(1)蒿坪河小流域降雨年度分布不均,暴雨集中型降雨产生径流和农业非点源污染的可能性最大。(2)0～5°耕地、5～10°耕地、10～15°耕地、栎林和果园平均径流系数分别为2.01%、2.98%、5.44%、16.47%和2.42%。陡坡地带的栎林在降雨侵蚀力大于0.5的时候开始产流,以超渗方式为主;果园在降雨侵蚀力大于2.5的时候开始产流,以蓄满产流为主;耕地产流受人为影响显著,产流界限不容易确定,在暴雨集中型降雨条件下以超渗产流方式为主。栎林和果园产流量与降雨侵蚀力均存在一定的线性相关性,R2分别为0.939和0.912。耕地由于受人为影响比较大,其产流与降雨侵蚀力关系波动较大,没有明显规律。暴雨集中型降雨条件下,10-15°耕地产流和0-5°、5-10°差异性显著(P<0.05),0-5°、5-10°耕地产流之间无显著差异。在小雨集中型降雨条件下,土壤结皮成为影响产流的主要因素。(3)氮的流失以溶解态为主,其来源主要是化肥的过量施用;磷的流失以颗粒态为主,主要来源于土壤侵蚀。坡耕地是产生非点源污染的主要源区。施肥后的前两次强降雨,耕地总氮的流失量表现出坡度之间的差异性,一般10～15°耕地和0～5°、5～10°之间差异性显著(p<0.05),但是在极端降雨条件下,如2008-7-18降雨,降雨侵蚀力达到了180,0～5°和5～10°耕地总氮流失量差异性也显著(p<0.05)。在暴雨集中型降雨条件下,10～15°耕地总磷流失量和0～5°、5～10°耕地之间差异性显著(p<0.05), 0～5°和5～10°耕地之间无显著差异性。此外陡坡栎林等山林地,氮磷输出总量也不容忽视,也是非点源污染产生的重要区域。(4)暴雨集中型降雨条件下,10～15°耕地泥沙流失量和0～5°、5～10°之间差异性显著(p<0.05),0～5°、5～10°之间无明显差异性,在强降雨条件下10～15°耕地水土流失严重。泥沙流失量年度差异性比较大,实验期内,2008年0～5°、5～10°、10～15°耕地、栎林和果园泥沙流失量分别为:142.54、191.50、1458.45、1253.31和211.64kg/hm2,2009年则分别为6.53、7.54、15.96、99.96和27.49 kg/hm2。10～15°耕地和陡坡栎林是土壤侵蚀的关键源区,应予以重视。(5)对大于10°的耕地实施“坡改梯”工程,在进行农事操作时,多关注天气情况,尽量避开强降雨,对于减少化肥和水土流失,降低非点源污染的产生有很重要的现实意义。更多还原

【Abstract】 In this paper, the characteristics of non-point source pollution in different slopes and land uses were studied in Haoping river watershed,which is a tributary of Laoguan river—the largest tributary of Danjiangkou Reservoir in Henan. 15 runoff ponds of five groups were built, and the rain, runoff and water quality were monitored. The results showed that:(1)the distribution of annual precipitation in Haoping watershed was variable, and the centralized storm rainfall was the main type generating non-point source pollution.(2)The average runoff coefficients of 0～5°, 5～10°, 10～15°cropland, oak forest and garden were 2.01%, 2.98%, 5.44%, 16.47% and 2.42% respectively. When rainfall erosivity (R) was greater than 0.5, oak forest in the steep slope began to generate runoff, and the main type was infliration excess runoff. When R was greater than 2.5, garden started to generate runoff, and the main type was saturation excess runoff.Cropland was dramatically affected by human, so it was not easy to determine the runoff boudary, and the main type was saturation excess runoff in centralized storm rainfall. The product of runoff and R showed a linear correlation in the oak forest(R2=0.939) and the garden(R2=0.912). The runoff and rainfall erosivity had no significant correlation in cropland, because it was significantly affected by human. In the condition of centralized storm rainfall, runoff was mainly affected by slope. The product of runoff in the cropland had significant difference between 0～5°, 5～10°and 10-15°cropland(P<0.05). In the condition of centralizd light rain, soil crust was the main factor affecting runoff.(3)The loss of nitrogen, whose main source was excessive application of fertilizer, was dominated by dissolved nitrogen, while the loss of phosphorus, whose main source was soil erosion, dominated by particulate phosphorus. Slope cropland was the major regional for generating non-point source pollution, the amount of total nitrogen loss had significant difference between 0～5°and 10-15°, 5～10°and 10-15°cropland(P<0.05) in the two previous heavy rainfalls after fertilization, and there was a significant difference between 0～5°and 5～10°cropland in extreme rainfall(R>180). In the condition of centralized storm rainfall, the amount of total phosphorus loss had significant difference between 0～5°and 10-15°, 5～10°and 10-15°cropland(P<0.05). It has a very important practical significance for implementing of terraced fields construction, taking agricultural activities to avoid heavy rain in the impaction of soil and water conservation, and reducing runoff and agricultural non-point source pollution. In addition, forest land such as oak was also important region for generating non-point source pollution, great attention should be paid.(4)In the condition of centralized storm rainfall, the amount of sediment loss had significant difference between 0～5°and 10-15°, 5～10°and 10-15°cropland(P<0.05). The sedements of different years had large difference, during the experimental period, the loss of sedements in 0～5°, 5～10°, 10～15°cropland, oak forest and garden were 142.54,191.50,1458.45,1253.31and 211.64kg/hm2 in 2008, and 6.53,7.54,15.96,99.96 and 27.49 kg/hm2 in 2009. 10～15°cropland and oak forest in steep slope are critical source area for soil erosion, great attention should be paid.(5) It has a very important practical significance for implementing of terraced fields construction, taking agricultural activities to avoid heavy rain in the impaction of soil and water conservation, and reducing runoff and agricultural non-point source pollution. In addition, forest land such as oak was also important region for generating non-point source pollution, great attention should be paid.更多还原