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The effect of N fertilizer application in rice field on the environmental quality of groundwater was evaluated using large undisturbed monolith lysimeters. Soil in lysimeters was silty-clay-loamy paddy soil (Haplaquept)with a pH of 6.5, 15.4g/kg organic C, 1.55g/kg total N, 88 mg/kg available N, 399 mg/kg Alabbas-P, 67.5 mg/kg exchangeable K, and 14.1 cmol/kg CEC. The lysimetry experiment was laid out at Hangzhou during the early-rice season (ER, May-Jul) and late-rice season (LR, Jul-Oct) in 1991—1994. Three plot treatments were established, i.e., urea plot (UN_(150), applied urea 150 kgN/ha per cropping season), ammonium bicarbonate plot (CN_(150), applied ammonium bicarbonate 150 kgN/ha per cropping season), and control plot (CK, no N application). All of the plots also received single superphosphate at 45kg P/ha and KCl at 75 kg K/ha. The
The effect of N fertilizer application in rice field on the environmental quality of groundwater was evaluated using large undisturbed monolith lysimeters. Soil in lysimeters was silty-clay-loamy paddy soil (Haplaquept) with a pH of 6.5, 15.4 g / kg organic C, 1.55 g / kg total N, 88 mg / kg available N, 399 mg / kg Alabbas-P, 67.5 mg / kg exchangeable K, and 14.1 cmol / kg CEC. The lysimetry experiment was laid out in Hangzhou during the early-rice season (ER, May-Jul) and late-rice season (LR, Jul-Oct) in 1991-1994. Three plot treatments were established, ie, urea plot , ammonium bicarbonate plot (CN 150, applied ammonium bicarbonate 150 kg N / ha per cropping season), and control plot (CK, no N application). All of the plots also received single superphosphate at 45 kg P / ha and KCl at 75 kg K / ha