Abstract: 【Objective】This study was to investigate the potential of decreasing plant for different plant species and cropping system to reduce nitrate accumulation in soil profile such as meadow cinnamon soil on North China plain. 【Method】 Crop, forage, forest and catch crops were used as materials in a field experiment, the soil, plant and root samples were collected and measured, and the reduction effects of several plant cultivation systems were analyzed. 【Result】 The results indicated that biomass and N uptake of grass monoculture or intercropping on the ground increased significantly with the cultivation period, and was significantly higher than crop rotation and catch crops after 2 years. Although poplar had the greatest biomass, N uptake was reduced significantly in the following year and less than grass monoculture or intercropping and close to crop rotation catch crops. Amount of nitrate reduction (0-200 cm) showed popla＜catch crops＜alfalfa and alfalfa+bromus and crop rotation＜tall fescue. Root zone and the deep nitrate accumulation of poplar had a strong leaching downward trend. The peak appeared in the depth of 80-100 cm and 120-180 cm where it was leaching 60 cm below the labeled place. Under catch crops, leaching of nitrate occurred to some extent for deep accumulation in the profile. There was a significant positive correlation between plant root length density and soil nitrate decrease in 0-100 cm soil layer.【Conclusion】 In the high nitrate accumulation soil, grass monoculture or intercropping can reduce soil nitrate content rapidly. Nitrogen absorption in the topsoil of tall fescue was more than other plants. Alfalfa had a advantage in the relatively long term restoration.

Key words: grass , crop , poplar , accumulative NO3--N , catch crops