『Abstract
　We conducted a greenhouse experiment to investigate the effects of nitrogenous fertilizer application on weathered particles of coal gob (WPCG). Different rates of nitrogenous fertilizer - low N (0.034 g N kg^-1 WPCG), medium N (0.068 g N kg^-1 WPCG), and high N (0.136 g N kg^-1 WPCG) - were applied, and two native grasses (Orchardgrass and Alfalfa) were mix-planted in each pot. The results showed that the biomass production were all significantly increased in low and medium N group compared with that in the control group, respectively, in aboveground or underground part (p＜0.01), but it was slightly increased in high n group. Compared with the control group, chlorophyll concentrations of Orchardgrass in medium N group and Alfalfa in low N group were all significantly increased (p＜0.05), but it was the lowest in high N group. n uptake efficiency was the highest in low N group. However, N, P, and K uptake efficiencies were all lowest in high N group. Moreover, the microorganism population in WPCG was greatly improved in low group. Compared with the control group, the numbers of bacteria, actinomycete, fungi, and nitrogen-fixing bacteria were significantly increased by 438％, 125％, 20％, and 258％, respectively (p＜0.05). After 120 days growth of Orchardgrass and Alfalfa, the percentage of particle diameter of WPCG was changed. The percentage of fine particles (＜3 mm) was increased by 99.4％. In conclusion, it will be a more efficient approach for the quick establishment of vegetation system to apply low nitrogenous fertilizer (0.034 g N kg^-1 WPCG) as an immediate treatment for nitrogen deficiency during the primary reclamation period on a large scale.

Keywords: Weathered particles of coal gob (WPCG); Nitrogenous fertilizer; Biomass; Nitrogen uptake efficiency; Microorganism population』

1. Introduction
2. Materials and methods
　2.1. WPCG and its characteristics
　2.2. Pot experiment
　　2.2.1. Particle proportion of WPCG
　　2.2.2. Experiment design
　　2.2.3. Sampling and measurement
　2.3. Statistical analysis
3. Results
　3.1. The biomass production of Orchardgrass and Alfalfa was increased significantly in low and medium N group
　3.2. The chlorophyll concentrations of Orchardgrass or Alfalfa were increased in low and medium N group
　3.3. The nitrogen uptake efficiency was the highest in low N group
　3.4. The microorganism population in WPCG was the highest in low N group
　3.5. The percentage of particle diameter of WPCG was changed after 120 days of grass growth
4. Discussion
5. Conclusion
Acknowledgments
References