By using in situ leaching device, a field experiment was conducted to study the nitrate leaching amount and density at 60 cm soil depth, nitrate accumulation in soil profile (0-80 cm) of poplar-wheat intercropping ecosystem. Four treatments were installed, no fertilization (N 0, 0 kg/hm 2) conventional fertilization (N 140, 140 kg/hm 2), reduced N application (N 70, 70 kg/hm 2), increased N application (N 210, 210 kg/hm 2). The results indicated a positive correlation between quantity of leachate water and precipitation, the poplar-wheat intercropping ecosystem can reduce the quantity of eluviate solution. The nitrate leaching loss increased according to the increasing N fertilization rate. In treatment spot N 210, the nitrate nitrogen loss from N fertilization at 60 cm soil depth was the greatest (13.89 kg/hm 2), it declined by 60.27% and 50.11% in poplar-wheat intercropping ecosystem away from the poplar row 0.5 m and 1.5 m, respectively. The nitrogen leaching and accumulation were significantly lower in poplar-wheat intercropping ecosystem, and variances of the distribution for soil nitrate nitrogen were significant.
