摘要
为了探究平原河网区域氮素垂向迁移及流失情况,本研究基于平原河网区农业活动施用的氮素通过包气带发生纵向迁移的实际情况,利用HYDRUS-1D软件中的水分运动和溶质运移模块构建适用于平原河网区的水氮模型,结合野外监测和室内淋溶试验对模型参数率定和验证,利用校验过的模型对区域氮素垂向迁移及流失情况进行模拟。结果表明:尿素主要分布在0~5 cm土壤,并在表层土壤中大量水解;氨氮和硝态氮主要分布在0~15 cm和0~35 cm土壤,且随着土壤深度增加,浓度均呈现先增加后减少的趋势。土壤深度每增加10 cm,硝态氮浓度减小约10 mg·L^(-1)。相对而言,硝态氮更易流失进入深层土壤,氨氮流失则对灌溉量响应更为明显。当灌溉量高于400 mL时,氮素流失量呈指数增加趋势。在综合考虑自然降雨、外源污染输入和土壤背景值的条件下,平原河网区进入地下水的氮素将远超国家Ⅲ类水质标准。
Based on the actual situation of the study area,the HYDRUS-1D model was used to simulate the migration characteristics of water and nitrogen in a plain river network area.The model parameters were calibrated and validated by combining field monitoring and indoor leaching experiments;therefore,vertical migration and loss of nitrogen in the research area were simulated using this verified model.The results showed that urea was hydrolyzed largely in the surface soil and was mainly distributed in 0~5 cm depth of the soil layer.Ammonia nitrogen and nitrate nitrogen were mainly distributed in 0~15 cm and 0~35 cm depths of the soil layer,respectively.The concentrations of these two pollutants basically showed the same tendency:both increased first and then decreased with increasing soil depth.It was estimated that when the soil depth increased by 10 cm,the nitrate-nitrogen concentration decreased by 10 mg·L^(-1),which meant that nitrate-nitrogen entered deep soil easily.Ammonia nitrogen loss owing to irrigation was clearly observed,especially when the irrigation amount was greater than 400 mL;however,nitrogen loss increased exponentially.Meanwhile,the amount of nitrogen entering into the groundwater environment in the plain river network area was much higher than that in the typeⅢwater quality standard,considering natural rainfall,input of exogenous pollutants,and soil background value.
作者
许雪婷
班如雪
金有杰
张毅敏
高月香
徐豪杰
XU Xueting;BAN Ruxue;JIN Youjie;ZHANG Yimin;GAO Yuexiang;XU Haojie(Nanjing Institute of Environmental Science,Ministry of Ecological Environment,Nanjing 210042,China;College of Environment,Hohai University,Nanjing 210098,China;Nanjing Automation Institute of Water Conservancy and Hydrology,Nanjing 210012,China)
出处
《农业环境科学学报》
CAS
CSCD
北大核心
2022年第2期400-410,共11页
Journal of Agro-Environment Science
基金
国家重点研发计划项目(2019YFB2102003)。
