The purpose of this study was to evaluate the effects of liquid manure to increase the yield of green manure in winter season, and to investigate the effect of green manure incorporation to increase the yield of maize grain and nutrient balance improvement in upland soil. The green manure used in this experiment was barley and hairy vetch with a mixed ratio of barley and hairy vetch (75:25), respectively. Liquid manure applied 0, 26, 52, 78, and 104 Mg ha -1 , respectively, and the half of the total amount was applied as basal fertilizer, and the other half was topdressing. Nitrogen inputs through liquid manure were 0, 7.1, 15.6, 21.5 and 28.4 kg ha -1 , respectively, and the phosphorus inputs were 0, 11.3, 22.6, 33.9 and 45.2 kg ha -1 , respectively. The yield of green manure crops increased significantly with the increase of liquid manure application, but the yield of hairy vetch decreased. In the summer season, the green manure crops were incorporated, and the compost was used in the conventional treatment. The yield of maize grain increased with increasing green manure yield. The yield of maize grain of green manure crops incorporation treatments was up to 81% compared to conventional cultivation treatment, however the two-year experiments showed an increase on maize grain yields in green manure incorporation treatment. In addition, the incorporation of green manure crops greatly improved the phosphorus balance in compared to conventional cultivation. Therefore, productivity improvement of green manure crops by utilizing liquid manure is thought to have significantly contributed to the improvement of maize grain yield and nutrient balance.