Study On Properties Of Succession And Artificial Control Measures Of Elymus Nutans Griseb Community

Based on the study on the correlation between vegetation characteristics and soil properties of degradation succession of natural Elymus nutans Griseb community, then study on the community characteristics after using ripping, fertilizing, resowing and other comprehensive agronomic measures to improve directly the natural grassland communities. The results showed that: a. With the degradation succession of Elymus nutans Griseb community, the dominance of Elymus nutans Griseb decreased significantly, species richness and species diversity index increased significantly; grasses functional group gradually declined, sedges and forbs functional group became prosperity gradually; in late succession, community characters tended to stabilize. b. The main features of the soil properties showed that soil organic matter, total N, total phosphor, NH+4-N, N03-N, soil moisture and bulk density increased gradually, in which total N, soil organic matter and NH+4-N increased significantly c. The dominance of Elymus nutans Griseb depended on the minimization of interspecific competition and the sustainable stability of soil fertility level, N elements in which had a leading role. The best time to add N to the soil that is at the peak period or pre-peak period of Elymus nutans Griseb dominance. d. After ripping, fertilizing, resowing and other comprehensive agronomic measures on the natural grassland, the proportion of Elymus nutans Griseb increased, species diversity changed from high to low, then from slow recovery to high, soil nutrient especially the available nutrient increased suddenly, followed by a sharp decline. e. Ripping and fertilizing play an important role in improving the important value of Elymus nutans Griseb, the role of resowing is relatively small, but the rational combination of three measures may extend the dominant position of Elymus nutans Griseb in the community; to maintain the higher weight and biomass of grasses in the community, it need to add the missing nutrition to the soil promptly.