title: [Dynamics of three kinds of nitrogen in surface water of rice field with an independent irrigation system].
abstract: Studies on the dynamics of NH4+, NO3- and TN concentrations in the surface water of paddy field with an independent irrigation system showed that the concentration of NH4+ and TN in surface water was increased to the maximum after 1day of each urea application, and then decreased rapidly with time. The ratio of NH4+/TN, NO3-/TN and (NH4+ + NO3-)/TN was increased firstly, and then decreased. NH4+ and TN could be used as the main indexes for the water pollution of the paddy field, and NO3- used as the assistant one. There existed a positive relation between the concentration of these three kinds of nitrogen and N application amount. Nine days after urea application was the key time to prevent the gross loss of the three kinds of nitrogen in the water surface of the paddy field. The simulation expressions of NH4+ and TN with time factor could be exponential, logarithmic, power or binomial, while NO3- had no appropriate expression. The simulation with factors of time and N application amount showed that the simulation expressions of NH4+ and TN were the same.
authors.affiliation: Ecology Research Institute, Zhejiang University, Hangzhou 310029, China. wqwwzju@163.com
authors.forename: Qiang
authors.initials: Q
authors.lastname: Wang
authors.forename: Jingping
authors.initials: J
authors.lastname: Yang
authors.forename: Jun
authors.initials: J
authors.lastname: Chen
authors.forename: Hongxing
authors.initials: H
authors.lastname: Shi
authors.forename: Chunfen
authors.initials: C
authors.lastname: Xu
mesh_terms: D000641:Ammonia / Q000032:analysis; D004784:Environmental Monitoring; D005308:Fertilizers; D009566:Nitrates / Q000032:analysis; D009584:Nitrogen / Q000032:analysis* / Q000737:chemistry; D012275:Oryza / Q000254:growth & development; D012987:Soil / Q000032:analysis*; D014867:Water / Q000032:analysis*; D014873:Water Pollutants / Q000032:analysis
chemical_list: D005308:Fertilizers; D009566:Nitrates; D012987:Soil; D014873:Water Pollutants; D014867:Water; D000641:Ammonia; D009584:Nitrogen