The Effect Of Simulation Clipping And Fertilizing Level On Plant Community And Function In Qinghai-Tibetan

This study, at the Pasture Land Station of Maqu in southern Gansu, setting 4 fertilizer addition levels and 6 mowing intensities, Our result showed that species richness decreased along fertilizing gradients, and the soil fertility treatments significantly affected aboveground biomass, with 30g/m²(NH₄)₂HPO₄ resulting in the highest levels of aboveground biomass.2) The species richness-productivity relationships change with temporal and spatial scales, There is an overall loglinear increase in species richness-productivity pattern on unfertilizing and 30g/m²(NH₄) ₂HPO₄. With 60g/m²(NH₄)₂HPO₄ resulting community structure severity change, there is an overall loglinear decrease in species richness-productivity pattern. There is no significantly affected with 120g/m²(NH₄)₂HPO₄ fertilizing. The mowing treatment did not significantly affect aboveground biomass. The soil fertility and mowing treatments significantly affected community compensation ability. These results indicated that community compensation ability was directly related to the soil fertility levels, so that fertilizer can enhanced community compensation. Different fertilizer levels and mowing treatments had different effects on compensatory responseswith compensation ablity increasing along fertilizing gradients. The least fertile soil and 30g/m² (NH₄)₂HPO₄ with one mowing event had a compensation ability two times greater than other treatment combinations. The 60g/m² (NH₄)₂HPO₄ soil fertility treatment and 120g/m²(NH₄)₂HPO₄ with two mowing events resulted in lower compensation ability.These above results provided valuable evidences for the studies on plants at meadows ecosystem and the researches of resource and grazing, and further knew that the natural ecosystem had different effects on the limited factors of environment and grazing. Meanwhile, the adaptive strategies of plants on limited nutrient were well discussed by measured correlated parameters. Our results indicated the adaptive mechanism of plants at different environments through three kinds of levels: species, functional groups and communities, and further showed the effects of disturbance, especial over-grazing, on the ecosystem of meadows. These researches had an important significance on the biological diversity protection, the global changes and regional continual development.