Comparative research on the influence of chemical fertilizer application and enclosure on alpine steppes in the Qinghai Lake area I structure and species diversity of the plant community

A study was conducted at the Sanjiao City Sheep Breeding Grassland Area of the Qinghai Province, which is located on natural alpine grassland on the north bank of Qinghai Lake. Nitrogen and phosphorous chemical fertilizers were applied to some of the alpine steppe, and area permanently enclosed in fences and that not enclosed was compared, to find the best approach to restore degraded grassland. After application of fertilizer, the importance value of excellent pasture showed an increasing trend, and the increase was greater within the fenced area than without. The natural alpine steppe showed the same trend with greater importance value of excellent pasture within fenced areas than that without. Man-imposed control strategies showed significant effects on the species richness of the plant communities. Plant communities with chemical fertilizer applied showed significant loss of species, and the number of species within the fenced area increased. Thus, it can be seen that both chemical fertilizer application and fencing can affect the species of plant communities.