Change Of Soil Organic Carbon Along Vegetation Degraded Gradient In Yak Meadow Park Of Mt. Jade Dragon

In the condition of global warming, it was the preferred solution that by increasing soil organic carbon reserves to mitigating climate change and to maintaining ecological process in the environment issues. Alpine meadow ecosystem, owes huge reserves of soil organic carbon due to its special geographical location and harsh environmental conditions of year-round low temperature and humidy. The degradation of Alpine Meadow will lead to significant changings of carbon cycle, which was caused by soil organic carbon content and reserves. The Alpine meadow was so sensitive to climate change, because its locating in the transition region that northwest monsoon region to the Tibetan Plateau. Recently years, the Alpine meadow in northwestern Yunnan is suffering different degree of degradation that was caused by human activities. In order to understanding the soil organic carbon’s changing that along the vegetation degradation gradient in northwestern Yunnan, we selected Mt. Jade Dragon Yak meadow Park as the research region and collected correlated researching data in July 2014. By using variation partitioning and generalized linear model (GLM) method, we studied the change of soil organic carbon that along the vegetation degradation gradient. The main results are summarized as follows:The soil organic carbon average density,which in Yak meadow park,was 17.01 kg/m2. Soil organic carbon stock was 2.64×108kg in the layer between 0-30cm, however it was 2.62×108kg when the meadow in Yak meadow Park had not degradated. The soil organic carbon stock in the all increased by 0.02×108kg due to the meadow vegetation degradation.In the upper layer (0-15cm) soil, organic carbon content showed a trend of decrease with the increase of degradation degree that along the meadow vegetation non degenerated(ND) into the high degradation(HD) of gradient. In the lower (15-30cm) layer soil, organic carbon content showed increased first and then decreased. In the vertical distribution of the soil layer, the soil organic carbon decreased significantly with the increase of soil depth in the three stages of non degradation(ND), light degradation(LD) and middle degradation(MD).The results of variation partitioning analysis showed that the two groups of vegetation and soil explanatory variables on both layers (0-15cm,15-30cm) of soil organic carbon changes have a high amount of explanation, respectively,95.4% and 81.4%. Specifically, in the upper soil layer,94.3% variance was explained by soil parameters and 81.1% was explained by vegetation parameters. Rrelative to the upper layer of soil, the soil parameters in the lower soil explained (74.6%) is far greater than the explained of vegetation parameters (41.8%). In upper soil organic carbon change in significant explanatory variables for soil parameters of soil bulk density(SBD) and soil total nitrogen(STN), vegetation parameters is mainly for the vegetation coverage(VTC); lower soil organic carbon dynamics in the main influence factors for soil factors of soil total nitrogen(STN) and soil pH value(SPH), vegetation coverage and vegetation parameters, vegetation height(VAH) and biomass.Along the vegetation degradation gradient, the upper (0-15cm) and soil organic carbon content in non degradation, light degradation and moderate degradation of three stages is mainly affected by the soil system, which set of soil parameters on the change of soil organic carbon in explained variance amount respectively 89.3%, 96.4% and 92.6, vegetation parameters group variance explained was respectively 9.4%,34.8% and 3.1%.For high degradation stages of vegetation system enhancement, it was explained 91.1%. Lower (15-30cm) layer soil organic carbon content in non degradation(ND) and light degradation(LD) in two stages is mainly affected by the soil, soil parameters of the amount of variance explained were 96.7% and 83.8%, vegetation parameters of explained variance were 20.5% and 18.8%. But to stage the main medium degradation,which affected by vegetation system, vegetation parameters and soil parameters of the amount of variance explained were 73.8% and 45.5%.Using the generalized linear model (GLM) changes in soil organic carbon to simulating four vegetation degradation stage and to predicting persistent vegetation degradation trend change of soil organic carbon. The results showed that the soil total nitrogen and vegetation coverage of two degradation as an independent variable regression equation simulation was the best, explaining the amount of up to 94% of the variance of upper layer soil organic carbon, the lower layer soil reaches 83%. Lasting meadow vegetation degeneration will result in continued loss of soil organic carbon content.The Yak Meadow Park management proposal was also presented in the paper: vegetation coverage could be a good indicator of soil organic carbon changes. For meadow management, we can through the observation of the vegetation coverage to evaluating the corresponding soil organic carbon content. Mild degradation vegetation was conducive to the accumulation of soil organic carbon, but light degradation meadow vegetation stage should be protected, which avoiding large losses of soil organic carbon.