【摘要】 云南抚仙湖流域农田面源污染日益严重,土壤污染物主要随地表径流进入湖泊,使湖泊受到污染。但目前的现场观测表明,农田区浅层地下水也已受到污染,地下水已成为污染物输移的路径之一。通过四组不同降雨强度作用下的室内土柱试验模拟土壤污染物向地下水的淋失迁移量,对降雨入渗过程中总氮、总磷、铵态氮和硝态氮的垂向迁移过程进行了分析,通过分时段处理来对各组实验中营养盐累积淋失量进行了计算。结果表明,硝态氮的垂向迁移能力和出流浓度均大于铵态氮,总氮和总磷的累积淋失量与累积降雨量呈自然对数关系;降雨强度对总氮的淋失作用明显,对总磷淋失量的影响则相对较弱。实验结果有助于揭示抚仙湖流域降雨作用下农田土壤中污染物的垂向迁移过程及其对农田浅层地下水的污染机制,并为污染物垂向迁移的数学模拟提供数据基础。更多还原

【Abstract】 Non-point source pollution in the Fuxianfu Lake catchment,Yunnan has been the main cause of eutrophication of the Fuxianfu Lake.Leaching loss of nutrients from the soil is not only one of the most important agricultural problems,but also the main factor causing nitrogen and phosphorus pollution of the water environment.Four soil columns sampled in the region were used in the laboratory experiment,which was designed to have four different rainfall intensities,to investigate migration and leaching loss of nutrients.Based on the obtained experimental data,characteristics of migration of total nitrogen,total phosphorus,nitrate-N and ammonia-N were analyzed,and cumulative leaching losses were calculated.Results show that nitrate-N moves relatively easily with water movement in the soil profile while ammonia-N can hardly do.A natural logarithm relationship was found existing between cumulative rainfall amount and cumulative leaching losses of nutrients in all the experimental conditions.Leaching loss of total nitrogen was mainly affected by rainfall intensity,while leaching loss of total phosphorus was not significantly related to rainfall intensity.The findings of this paper may help explore distribution and migration of nutrients in agricultural lands,and mechanism of agricultural activities polluting groundwater.更多还原