三峡库区消落带农用坡地氮素流失特征及其环境效应

发布时间：2018-03-25 21:17

本文选题：三峡水库　切入点：消落带　出处：《长江流域资源与环境》2017年08期

【摘要】：三峡库区消落带坡地的自发农用较为常见,消落带的这种利用方式可能加剧养分流失并对库区水环境造成影响。通过对库区2011~2013年3个落干期消落带农用坡地的地表径流、壤中流中氮素形态与浓度进行定位监测,研究消落带农用坡地氮素流失特征及其环境效应。结果表明:常规施肥下,消落带农用坡地侵蚀模数为1 443 kg/(hm~2·a),落干期内坡地平均径流量为230 mm,径流系数为0.58,其中壤中流流量占总径流量的77%。历次降雨产流事件中常规施肥处理时,地表径流、壤中流中TN平均浓度分别是4.85±0.85、20.73±2.05 mg/L,落干期地表径流(泥沙)和壤中流的TN流失量分别为6.63±1.19、35.22±3.38 kg/hm~2,分别占当季施肥量的2.2%、11.7%。可见,随壤中流流失是三峡库区消落带农用坡地氮素流失的主要途径。与常规施肥处理相比,减量施肥处理使地表径流(泥沙)、壤中流TN流失通量分别显著降低了25%、48%,表明减少氮肥用量可以显著降低消落带农用带来的环境风险,建议消落带农用地氮肥进行减量施肥,使其既不影响作物产量,也显著降低氮流失。
[Abstract]:The spontaneous agriculture of sloping land in the three Gorges Reservoir area is more common, and this way of utilization may aggravate the nutrient loss and affect the water environment of the reservoir area. The surface runoff of the agricultural sloping land in the three declination zones in the reservoir area during the period from 2011 to 2013 is studied. Nitrogen forms and concentrations in soil flow were monitored to study the characteristics of nitrogen loss and its environmental effects on agricultural sloping land in the declination zone. The results showed that: under conventional fertilization, nitrogen loss and nitrogen loss in sloping land were studied. The erosion modulus of agricultural sloping land is 1 443 kg/(hm~2 / a, the average runoff of slope land is 230mm and the runoff coefficient is 0.58mm during the dry period, and the runoff in soil is 77% of the total runoff. The average TN concentration in soil was 4.85 卤0.85 卤0.85 卤20.73 卤2.05 mg / L, and the TN loss of surface runoff (sediment) and soil flow were 6.63 卤1.193.22 卤3.38 kg / hm ~ (-2), respectively, which accounted for 2.2g / L of fertilization in the current season. The loss of nitrogen along with soil flow is the main way of nitrogen loss in agricultural sloping land in the three Gorges Reservoir area, which is compared with conventional fertilization. The nitrogen loss fluxes of surface runoff (sediment and soil) were reduced by 25% and 48%, respectively, which indicated that reducing nitrogen fertilizer application could significantly reduce the environmental risk brought about by agriculture in the drop zone. It was suggested that nitrogen fertilizer should be reduced and fertilized. So that it will not affect crop yield, but also significantly reduce nitrogen loss.
【作者单位】：重庆师范大学地理与旅游学院;中国科学院山地表生过程与生态调控重点实验室;中国科学院成都山地灾害与环境研究所;
【基金】：国家自然科学基金重大项目(41430750)“三峡库区支流消落带土-水界面磷素流失过程与通量” 中国科学院STS项目(KFJ-SW-STS-175-02)“三峡库区生态清洁小流域建设技术体系试验示范”~~
【分类号】：X141;X143

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