Soil carbon stock and its changes in northern China's grasslands from 1980s to 2000s
Soil carbon stock and its changes in northern China's grasslands from 1980s to 2000s
复制标题
DOI：
10.1111/j.1365-2486.2009.02123.x
复制
发表时间：
2010-11
影响因子：
11.6
通讯作者：
Yuanhe Yang;Jingyun Fang;Wenhong Ma;Pete Smith;A. Mohammat;Shaopeng Wang;Wei Wang
中科院分区：
文献类型：
--
作者：
Yuanhe Yang;Jingyun Fang;Wenhong Ma;Pete Smith;A. Mohammat;Shaopeng Wang;Wei Wang
气候变暖可能加速土壤有机碳的分解，导致土壤碳释放量增加，从而对气候变化产生正反馈作用。然而，在过去的二十年中，草地生态系统的SOC动态仍然存在争议。在这项研究中，我们估计的规模在北方中国草原使用981土壤剖面调查327个站点在全国北方部分在2001-2005年。我们还研究了SOC库存的变化，通过比较目前的测量与历史记录的275个土壤剖面来自中国的全国土壤资源清查在20世纪80年代。结果表明，中国北方草地表层30 cm土壤有机碳储量为10.5 Pg C（1 Pg=1015 g），平均密度（单位面积碳储量）为5.3 kg C m−2。土壤有机碳密度（SOCD）与年平均气温无显著相关性，但与年平均降水量呈正相关。SOCD随着土壤湿度的增加而增加，当土壤湿度超过30%时达到稳定状态。站点水平的比较表明，草地SOC储量在过去20年中没有显著变化，变化为0.08 kg C m−2，在95%置信区间范围为-0.30至0.46 kg C m−2。样带尺度的比较证实，从20世纪80年代到21世纪初，草地土壤有机碳储量保持相对稳定，这表明中国北方草地土壤在过去20年中一直处于碳中和状态。
Climate warming is likely to accelerate the decomposition of soil organic carbon (SOC) which may lead to an increase of carbon release from soils, and thus provide a positive feedback to climate change. However, SOC dynamics in grassland ecosystems over the past two decades remains controversial. In this study, we estimated the magnitude of SOC stock in northern China's grasslands using 981 soil profiles surveyed from 327 sites across the northern part of the country during 2001–2005. We also examined the changes of SOC stock by comparing current measurements with historical records of 275 soil profiles derived from China's National Soil Inventory during the 1980s. Our results showed that, SOC stock in the upper 30 cm in northern China's grasslands was estimated to be 10.5 Pg C (1 Pg=1015 g), with an average density (carbon stock per area) of 5.3 kg C m−2. SOC density (SOCD) did not show significant association with mean annual temperature, but was positively correlated with mean annual precipitation. SOCD increased with soil moisture and reached a plateau when soil moisture was above 30%. Site‐level comparison indicated that grassland SOC stock did not change significantly over the past two decades, with a change of 0.08 kg C m−2, ranging from −0.30 to 0.46 kg C m−2 at 95% confidence interval. Transect‐scale comparison confirmed that grassland SOC stock remained relatively constant from 1980s to 2000s, suggesting that soils in northern China's grasslands have been carbon neutral over the last 20 years.