A field experiment was established on a representative sandy soil field to evaluate the effect of nitrogen(N) fertilizer
and irrigation application rates on nitrate (NO3--N) present in the soil profile during two consecutive years (2006-
2007). The results revealed that crop yields were not significantly enhanced at N application rate over than 225 kg/ha
and were not significantly reduced when 75% of traditional irrigation rates (12000 m3/ha) were supplied. The
amounts of NO3--N accumulation in soil ranged from 9.81 to 87.83 kg/ha significantly increased with N application
rates. Compared with reduced irrigation rates, NO3--N accumulations were obviously decreased in the 0-100cm soil
layer but increased in the 200-300 cm soil layer on traditional irrigation rate. The results of this study indicate that
excess N fertilizer and irrigation application rates have been provide for crop, and cause more NO3--N leaching.
However, there was a great potential for reducing N fertilizer and irrigation water inputs to mitigate nitrate
accumulation and leaching in the profiles of this sandy farmland region.