Dynamics of nitrogen and phosphorus in paddy field under deep application condition of urea pill and its pollution-reducing potential
Article
Figures
Metrics
Preview PDF
Reference
Related
Cited by
Materials
Abstract:
Dynamics of the pollutants such as nitrogen, phosphorus and the suspended particulates in the field water and soil and its pollution-reducing potential are investigated in the rice plant returning-green stage using deep application technique of urea pill with the application depth of 3, 7 and 11 cm (expressed as t-3, t-7 and t-11, respectively) based on the micro-zone simulation field experiments. Results show that nitrogen content in the field water gradually decreases within 5~7 d after deep allocation of urea, and reaches the low level after the seventh day. NO-3-N concentration is higher than NH+4-N, but there is little difference between treatments. As the pollution source is concerned, NO-3-N in the field water should be considered. There isn’t any correlation between nitrogen content in the water and urea application depth in the field. By contrast with blank treatment（expressed as t-c）, NO-3-N, NH+4-N and TN contents in the field water with deep application of urea pill decrease 29%～47%, 64%~89% and 79%～97%, respectively. The TP and DP are in the high level in the field water with t-3 and t-7. The TP, DP and SS concentration in the field water with t-11 decrease 32%～73%, 92%～99% and 50%～80%, suggesting that deep application of urea pill into 11 cm layer of the field should have a significant pollution-reducing potential and become one of effective measures to control non-point source pollution of agricultural system.
