Study On Degraded Succession Characters Of Artemisia Desert Grassland At Northern Slope Middle Part In Tianshan Mountain

This study focuses on artemisia desert grassland degraded succession at northern slope middle part in Tianshan Mountain, and cluster analysis is adopted to divide the degraded stages. Applying diversity index in the different degraded stages, the soil seed bank and main species nutrition is analyzed. The result show:1,The degraded succession series may be divided into four stages, that is non-degradation, media-degradation, heavy-degradation and over-degradation. With the increase of succession degree, the main plant species change.2,From non-degradation to over-degradation,αdiversity firstly increases and then falls, it is highest in media-degradation stage. And the plant species substitute is few in neighbor stages, grazing disturbance affects species diversity and it is in accordance with"media disturbance theory". Grassland productivity decreases while the diversity increases.3,With the increase of degraded succession degree, the CP content increases and the CF decreases in the main plant species. The feeding value becomes increasingly from bad to worse with the increasing degree of degradation because of the decrease of grass nutrient concent.4,The quantity sequence of soil seed bank in different stages is that non-degradation>over-degradation>media-degradation>heavy-degradation. There is greatly dissimilarity in different degraded stages soil banks and the seed of artemisia only exists in non-degraded stages. The number of the soil seed falls while the soil's deep increases. The similarity of plant vegetation and soil seed bank is small.