模拟放牧对天山北坡草甸草原生态系统碳储量的影响

为了揭示模拟放牧对天山北坡草甸草原有机碳储量的影响,在2012-2013年采用刈割模拟放牧方式设置休牧、轻牧、中牧、重牧4个处理,研究了不同放牧强度下地上活体植物、凋落物、根系和土壤的有机碳储量的变化。研究表明,随着放牧强度的增大,地上植被生物量碳储量、凋落物碳储量和总碳储量均表现为休牧轻牧中牧重牧;根系碳储量呈轻牧休牧中牧重牧,与轻牧相比,中牧和重牧分别下降了42.25%和72.41%;土壤碳储量表现为休牧中牧轻牧重牧。随着土壤深度的增加,根系碳储量逐渐减小;土壤有机碳密度随土壤深度增加则呈现不同的变化,总体呈现下降趋势;根系和土壤碳储量表层化趋势显著,0-20cm土层约占总碳密度的40%。碳储量的含量表现为土壤根系地上生物量,土壤有机碳密度最多,占85%以上;凋落物碳储量最少。

Effect of simulated grazing on carbon storage of meadow grassland ecosystem in the north slope of Tianshan Mountain

In order to evaluate the potential effects of grazing intensity on organic carbon storage in the north slope of Tianshan Mountain meadow grassland,organic carbon storage in plant biomass,litter,root and soil were analysis in the steppes with four simulated grazing intensities (no grazing,light grazing,moderate graz-ing,heavy grazing)in 2012—2013.The results showed that the organic carbon storage in total,plant biomass and litter decreased with the increase of intensity.The carbon storage in root decreased in the following order:light grazing > no grazing > moderate grazing > heavy grazing and moderate grazing decreased by 42.25%and heavy grazing decreased by 72.41% compared with light grazing.The carbon storage in soil decreased in the following order:no grazing > moderate grazing > light grazing > heavy grazing.With the increase of soil depth,the carbon storage in roots gradually reduced and the changes of organic carbon density in soil varied which had an overall decline trend.The organic carbon storage in root and soil surfaced significantly.The car-bon storage in the 0—20 cm soil layer account for 40% of the total carbon and the carbon storage decreased in the following order:soil > root > ground biomass.The organic carbon storage in soil was highest which ac-count for more than 85% whereas the carbon storage in litter was the least.