Effects of different grazing intensities on salinization grassland plant economic groups in Northern Shanxi Province

Through setting up five grazing levels: no grazing (CK), light grazing (LG), moderate grazing (MG), heavy grazing (HG) and extreme grazing(EG), species changes of grassland communities in Northern Shanxi Province were studied to determine a reasonable grazing capacity and further optimize the utilized patterns and efficiency of the grassland. The research showed that with the grazing intensity increasing, the proportion of Gramineae grasses were decreased and there were significant differences (P<0.05) in CK compared with in LG, MG, HG and EG; the proportion of legume forages were increased, the differences among CK, LG, MG, HG, and EG were not obvious; the proportion of Compositae plants were decreased and the differences in EG compared with in CK, LG, MG and HG were significant(P<0.05); the proportion of Potentilla plants were increased and there were significant differences (P<0.05) between CK and LG; and the proportion of forb group was decreased and there were significant differences (P<0.05) in CK compared with in LG, HG and EG. The grassland quality indexes of grasses, legume forages and Compositae plants were decreased, while those of Potentilla plants and forbs were increased with the grazing intensity increase.