Abstract: The height of Aneurolepidium chinense on Songnen grassland is decreased after early and lately burning, especially in late burned plot.No significant difference in its individual weight is found, the difference in production is mainly depended on its density.After burning, leaf number is increased, leaf size is widened, but leaf length is longer in early burned plot than in late one.The height growth of Phragmites communis and Carex duriuscula is affected by buring, but difference of Carex duriuscula in later growth period is disappeared.

Key words: Songnen grassland, Burning, Individual growth, Aneurolepidium chinense, free-living nitrogen-fixing bacteria, soil, associate nitrogen-fixing bacteria, phyllosphere.