中文摘要：

为了探究荒漠土壤活性有机碳组分对禁牧年限的响应,以伊犁绢蒿（Seriphidium transiliense）荒漠草地为研究对象,对不同禁牧年限（禁牧时间为0 a,1 a,4 a,11 a）荒漠草地0~50 cm的土壤有机碳（SOC）、易氧化碳（ROC）、易氧化碳分配比例（PROC）、轻组组分比例（LFR）、轻组有机碳（LFOC）、颗粒组分比例（PFR）、颗粒有机碳（POC）进行对比分析。结果表明：随着禁牧年限增加,0~10 cm土层SOC含量基本呈先降后升趋势,0~50 cm土层ROC、PROC总体呈增加趋势;与对照相比,禁牧区5~10 cm土层LFR、LFOC显著增加（P〈0.05）,0~50 cm土层PFR显著降低,POC变化不明显。总之,禁牧对SOC、POC影响较小,对ROC、PROC、PFR、5~10 cm土层LFR和LFOC影响较大,可作为伊犁绢蒿荒漠土壤对禁牧响应的敏感指标。

英文摘要：

In order to explore th e response of soil active organic carbon fractions to grazing exclusion, this paper compared total soil organic carbon, readily oxidizable carbon, light fraction of organic carbon, particulate organic carbon at 0- 50 cm depth of soil in Seriphidium transiliense desert under different grazing exclusion years（including0 year, 1 year, 4 years and 11 years）. The results showed that total soil organic carbon at 0- 10 cm soil layer appeared decreased at first and then increased with increasing grazing exclusion years, while readily oxidizable carbon and its distribution ratio to the total were increased at 0- 50 cm soil layer. The light fraction organic carbon and its component ratio at 5- 10 cm soil layer were significantly higher after grazing exclusion（P〈0.05）. Particulate organic carbon at 0- 0 cm soil layer did not change significantly after grazing exclusion, while particulate component ratios decreased significantly（P〈0.05）. In a word, the responses of readily oxidizable carbon and its distribution ratio,particulate component ratio, and light fraction of organic carbon and its component ratio at 5- 10 cm soil layer to grazing exclusion were more sensitive than total soil organic carbon. Those parameters could be used as sensitive indicators to grazing exclusion in Seriphidium transiliense desert.