Abstract: Leymus chinensis can grows in different typical steppe in the Inner Mongolian Plateau. In the same season, we invested and contrasted different typical Leymus chinensis which grows in different regions, such as desert grassland, typical grassland and meadow grassland etc. The number of leaves was basically stable, whereas heigh of plant, length of leaf, width of leaf,leng th/ width of leaf, dry weight per m2 and their energy value etc. Were all increased with the increase of precipitation from west to east . In order to protect the resource of grassland,we must attach importance to the practical productivity of the grassland, as well as area of grassland, when we estimate the maximum capacity of carring livestock on grassland.

Key words: microorganism, PCBs, dechlorination, sediment, soil.