摘要
农田非点源污染是最普遍的非点源污染类型之一,直接威胁北京市密云水库的水质状况;施用化肥是农田非点源污染物的主要来源。以北京市山区的农田化肥施用现状为基础,紧邻密云水库布设径流试验小区,种植当地的主要作物——夏玉米,设置常规(施肥)和对照(不施肥)2种处理,分析天然降雨条件下,施肥对农田地表氮和磷流失的影响。结果表明:施肥显著提高地表径流中氨态氮的浓度,但对径流硝态氮、总氮、可溶磷和总磷的影响有限;附着于泥沙上的颗粒态磷质量分数因施肥显著增加,但颗粒态氮质量分数仅在底肥施用后的首次产流中,表现出较大差异;泥沙是地表径流中氮和磷流失的主要载体,试验期间常规和对照小区,氮随泥沙流失负荷分别占氮流失总量的58.6%和53.6%,磷随泥沙流失负荷占比分别为97.2%和96.5%。研究结果可为密云水库流域农业生产管理和非点源污染治理提供参考。
[Background] Agricultural non-point source pollution is one of the most common non-point source pollution types, posing a great threat on the water quality of Miyun Reservoir in Beijing.Fertilization is the primary source of agricultural non-point source pollutants. The current study is aimed to analyze the impact of fertilization on nitrogen（ N） and phosphorous（ P） losses due to agricultural surface runoff and soil erosion. [Methods] Six 5 × 2 m runoff plots were established next to the Miyun Reservoir,on which summer corn was planted. Half of them received no fertilizer and the other half were fertilized according to the local customs,i. e.,applying compound fertilizer（ N∶ P2O5∶ K2 O = 15∶ 15∶ 15）as the base fertilizer at the day of sawing and topdressing urea after the elongation stage. Runoff sampleswere collected and analyzed for the determination of different forms of N and P pollutants for seven natural rainfall events during the growing season of summer corn in 2009. [Results] According to the contrast experiment, fertilization, especially topdressing urea, significantly increased the concentration of ammonia-N in surface runoff,but exerted little impact on nitrate-N,total N,and dissolved P or total P.The contents of sediment-bound P were significantly higher in the runoff from the fertilized plots,compared to the ones without fertilization. In contrast,obvious difference in sediment-bound N was only observed in the first runoff event after the application of base fertilizer. It was apparent that N losses with surface runoff and soil erosion was not only influenced by fertilization,but also closely related to the method of fertilizer application. For instance,topdressing urea obviously increased runoff N; whereas,sediment-bound N was typically regulated by the application of base fertilizer. The more losses of N from the fertilized plots,compared to the non-fertilized ones,were mainly originated from their elevated runoff and erosion modulus. Both N and P were mainly transported with sediments. Sediment-bound N accounted for 58. 6% and 53. 6% of total N losses for the fertilized and unfertilized plots,respectively.The contributions of sediment-bound P were even higher,and the corresponding percentages were 97. 2%and 96. 5% for the fertilized and unfertilized plots,respectively. [Conclusions] These findings hold important implications for the agricultural management and non-point source pollution regulation in the Miyun Reservoir Watershed. Both the rate and method of fertilization are critical for the management of croplands there,thereby for the water quality of Miyun Reservoir. Furthermore,it is necessary to adopt appropriate soil and water conservation measures to reduce surface runoff and soil erosion,especially the latter,from the mountainous areas of the watershed.
作者
王丽娟
杨扬
郑娟娟
刘瑛娜
郭乾坤
王大安
刘宝元
WANG Lijuan YANG Yang ZHENG Juanjuan LIU Yingna GUO Qiankun WANG Da＇an LIU Baoyuan(State Key Laboratory of Earth Surface Processes and Resource Ecology, School of Geography, Beijing Normal University, 100875, Beijing, China China Institute of Water Resources and Hydropower Research, 100048, Beijing, China)
出处
《中国水土保持科学》
CSCD
北大核心
2017年第1期97-104,共8页
Science of Soil and Water Conservation
基金
北京师范大学青年教师基金项目"坡面养分流失过程的室内模拟试验研究"(2014NT04)
国家自然科学基金创新研究群体项目"地表过程模型与模拟"(41621061)
关键词
施肥
农田
地表径流
氮
磷
天然降雨
密云水库
fertilization
cropland
surface runoff
nitrogen
phosphorous
natural rainfall
Miyun Reservoir
