Increase in soil organic carbon stock over the last two decades in China's Jiangsu Province
Increase in soil organic carbon stock over the last two decades in China's Jiangsu Province
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DOI：
10.1111/j.1365-2486.2008.01792.x
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发表时间：
2009-04-01
影响因子：
11.6
通讯作者：
Wu, Xinmin
中科院分区：
文献类型：
--
作者：
Liao, Qilin;Zhang, Xuhui;Wu, Xinmin
对区域和国家表土有机碳 (SOC) 库变化的估计可能有助于评估土壤通过土壤固碳 (C) 来减缓温室气体 (GHG) 排放的作用。然而，对确切缓解作用的理解常常受到与不同方法相关的库存估计的不确定性的限制。本文利用1982年土壤调查和2004年地质调查获得的中国江苏省表土（0-20 cm）SOC测量数据的土壤数据库，分析了土壤组间和土壤区域间表土SOC的变异性，并估算了该省过去20年发生的SOC库变化。土壤调查数据来自随机采集的 662 690 个样品的测量，而地质调查数据则来自使用 2 km x 2 km 网格采集的 24 167 个样品。分别对1982年和2004年不同类别土类、土区和行政城市的SOC值进行了统计分析。然后计算表土 SOC 储存量，并估算每个采样时间的省表土 SOC 储存量。土壤组别、土壤区域和不同城市之间的SOC水平存在显着差异。与 1982 年使用的随机抽样方法相比，2004 年地质调查的网格抽样得出的表土 SOC 平均值随土壤组和土壤空间分布的变化较小。在两个采样时间中，土壤组的 SOC 变化均大于土壤区域的变化，尽管土壤分类类别之间的 SOC 变化小于空间类别内的变化。土壤有机碳水平随土壤类别的变化很小，可以用粘土含量来解释。然而，稻田占耕地总面积的比例决定了地区和市的平均 SOC 水平。全省平均表土 SOC 含量由 1982 年的 9.45 g kg(-1) 增加到 2004 年的 10.9 g kg(-1)，全省表土 SOC 总储量由 1982 年的 149.0 ± 58.1 Tg C 提高到 2004 年的 173.2 ± 51.4 Tg C，相当于全省平均 SOC 固存率0.16 +/- 0.09 ℃ 公顷(-1)年(-1)。过去二十年的有机碳固存趋势部分归因于农业生产的提高，以每公顷粮食产量为标志。 SOC库变化的结果表明，1980-2000年期间，中国江苏土壤存在显着的碳固存，水稻管理在区域SOC储存和固存能力中发挥着重要作用。
Estimates of regional and national topsoil soil organic carbon (SOC) stock change may help evaluating the soil role in mitigation of greenhouse gas (GHG) emissions through carbon (C) sequestration in soils. However, understanding of the exact mitigation role is often constrained by the uncertainty of the stock estimation associated with different methodologies. In this paper, a soil database of topsoil (0-20 cm) SOC measurements of Jiangsu Province, China, obtained from a soil survey in 1982, and from a geological survey in 2004, was used to analyze the variability of topsoil SOC among soil groups and among soil regions, and to estimate the change in SOC stocks that have occurred in the province over the last two decades. The soil survey data was obtained from measurements of 662 690 randomly collected samples, while the geological survey data was from 24 167 samples taken using a 2 km x 2 km grid. Statistical analysis was conducted on SOC values for 1982 and 2004 for different categories of soil groups, soil regions, and administrative municipalities, respectively. Topsoil SOC storage was then calculated and the provincial topsoil SOC stock was estimated for each sampling time. There were remarkable differences in SOC levels between soil groups and soil regions and different municipalities. The grid sampling with the geological survey in 2004 yielded smaller variability of topsoil SOC averages, both with soil groups and with soil spatial distribution than the random sampling method used in 1982. Variation of SOC was greater with soil groups than with soil regions in both sampling times, although it was less variable across soil taxonomic categories than within a spatial category. Little variance of the SOC level with soil groups could be explained by clay content. However, the prevalence of paddy fields in the total cropland area governed the regional and municipal average SOC levels. The average provincial topsoil SOC content increased from 9.45 g kg(-1) in 1982 to 10.9 g kg(-1) in 2004, and the total provincial topsoil SOC stock was enhanced from 149.0 +/- 58.1 Tg C in 1982 to 173.2 +/- 51.4 Tg C in 2004, corresponding to a provincial average SOC sequestration rate of 0.16 +/- 0.09 t C ha(-1) yr(-1). The SOC sequestration trend for the last two decades could be, in part, attributed to the enhanced agricultural production, symbolized by the grain yield per hectare. The results of SOC stock changes suggest a significant C sequestration in soils of Jiangsu, China, during 1980-2000, with paddy management playing an important role in regional SOC storage and sequestration capacity.