Nitrogen leaching from paddy field under different fertilization rates.

cm soil layers. Results showed that during the paddy growth, NH4 + -N was the main form of nitrogen with a high environment risk. The range of NH4 + -N /TN 4 + days after three fertilizer application rates; the highest NH4 + -N concentrations were about 38.38 mg L-1 -1 or N4 were observed in the two layers between the other four fertilizer application rates.