氮在河北平原潮土和地下水迁移转化机制

通过室内土柱淋滤试验,揭示氨氮、硝酸盐氮、亚硝酸盐氮在潮土和地下水中的迁移转化规律,并确定迁移数学模型.结果表明:在施氮周期内,淋出液氨氮浓度最高为15.86 mg/L,最低为0.09 mg/L,平均为2.02 mg/L,超标10.1倍；亚硝酸盐氮浓度最高为37.456mg/L,最低为0.002 mg/L,平均为4.854 mg/L,超标242.7倍;硝酸盐氮浓度最高为16.35 mg/L,最低为2.12 mg/L,平均为6.51 mg/L,未超标.当潮土中硝化作用强时,硝酸盐和亚硝酸盐氮浓度升高,氨氮浓度降低.当反硝化作用增强时,硝酸盐氮浓度降低,氨氮浓度升高.地下水中主要的污染物质为氨氮和亚硝酸盐氮(硝酸盐氮低于Ⅲ类标准).氮在河北平原潮土和地下水中的迁移过程可以用所建模型进行定量预测.

Migration and Transformation of Nitrogen in Fluvo-aquic Soil and Groundwater of Hebei Plain

To reveal the migration and transformation rule of nitrogen in fluvo-aquic soil and groundwater of Hebei Plain and determine the migration mathematical model,the migration and transformation rule of ammonia nitrogen,nitrate nitrogen,nitrite nitrogen in fluvo-aquic soil and groundwater were revealed by the soil column leaching experiment.The results indicated that within nitrogen application period,the highest concentration of ammonia nitrogen is 15.86 mg/L,the lowest is 0.09 mg/L,an average of 2.02 mg/L,exceeding 10.1 times;the highest concentration of nitrite nitrogen 37.456 mg/L,the lowest concentration of 0.002 mg/L,the average concentration of 4.854 mg/L,exceeding 242.7 times;the highest concentration of nitrate nitrogen 16.35 mg/L,the lowest concentration of 2.12 mg/L,the average concentration of 6.51 mg/L,and not excessive.When the nitrification is dominant,the concentrations of nitrate and nitrite nitrogen increase and the concentration of ammonium nitrogen decrease.On the contrary,denitrification enhancements reduce the concentration of nitrate nitrogen and increase the concentration of ammonium nitrogen.The main pollutants in the groundwater for ammonium nitrogen and nitrite nitrogen(nitrate nitrogen concentration is lower than the class Ⅲ standard).The migration and transformation rule of nitrogen in fluvo-aquic soil and groundwater of Hebei Plain can be predicted quantitatively by the mathematical model.