Changed Trend Of Mountain Tall Grass Meadow Community Under Different Utilization Form

The mountain tall grass meadow is cream of Xinjiang natural grassland which is used mostly mowing in production. It is the important base of mowing and storage winter grass. It occupied very important position in traditional seasonal stockbreeding of Xinjiang. However, people ignored reasonably utilization of mountain tall grass meadow in past; and lacked scientific management for mountain meadow. The much mountain meadow which is fitted mowing was used grazing pasture in summer and autumn; the forage was trampled by livestock and fell down. It did not fully exert its production potential because of waste and low use. Presently, mowing, mowing + grazing and grazing are basic utilization form in Xinjiang mountain tall grass meadow. Are there utilization forms reasonable? What problems dose it exist? These questions needed scientific and reasonable conclusion. So, to counter the existing problems in mountain tall grass meadow utilization in Xinjiang, the 3 different utilization forms (mowing form, mowing+grazing form, and grazing form) of mountain tall grass meadow have been researched in Ju Hua Tai, Urumqi City with field measure and laboratory analysis. The community characteristic, plant chemical compositions and soil nutrients have been measured in field and laboratory. Community diversity and quantitative structure have been analyzed in laboratory. For all these, the purposes are: (1) evaluating mountain meadow degenerate reason in same vegetation type with different utilization form. (2) providing scientific basis for reasonable utilization, prevention and restoration mountain meadow.The results are showed as follows:(1)After through 24 years utilization, in mowing form, Elytrigia repense + Bromus inermis + Geranium pratense + Phlomis pratensis succession Phlomis pratensis + Alchemilla tianschanica + Achillea millefolium; in grazing form, Geranium pratense + Alchemilla tianschanica + Dactylis gglomerata succession Phlomis pratensis + Elytrigia repense + Achillea millefolium + Trifolium repens; in mowing + grazing form, Geranium pratense + Bromus inermis + Alchemilla Tianschanica succession Phlomis pratensis + Bromus inermis + Achillea millefolium.(2)In 2006, above-ground biomass of mowing + grazing form is 789.4 g/m2, higher than 1982. Above-ground biomass in 2006 is lower than 1982 in other utilization forms.(3)In mowing + grazing form and grazing form, Shannon-Wiener index, Simpson index and Pielou index in 1982 are bigger than in 2006. But, in mowing form, Shannon-Wiener index, Simpson index and Pielou index in 1982 are smaller than in 2006. In 2006, Shannon-Wiener index, Simpson index and Pielou index of mowing form are bigger than other utilization forms.(4)In mowing + grazing form, crude protein content is 11.16%, crude fat content is 3.3%, and they are the highest; Crude fiber content is 22.2% and is the lowest. Nitrogen-free extract content is 44% and highest in grazing form.(5)In mowing form, soil organic matter contents is the highest in 0~5 cm, 5~10 cm and 20~30 cm, they are 171.5595 g/kg, 151.5664 g/kg and 85.2842 g/kg, respectively. In grazing form, soil total N and available N content are highest in each layer, and soil available K and available P are the biggest in 0~5 cm. Total P content and total K content are not significant change.