Field experiments were conducted in the wetland reservoir sub-irrigation system (WRSIS) in Gaochun County, Jiangsu Province, in order to study the characteristics of dynamic change of nitrogen in the surface water and underground drainage water in paddy fields with different amounts of N fertilizer. The results show that the concentrations of TN and NH4+ -N in the surface water reached the maximum values one day after fertilization, and decreased rapidly seven days after fertilization by 70% to 76% and 83.5% to 85.5% , respectively. The rates of ρ(NH4+-N)/ρ(TN) and ,ρ(N展开▼
