School of Geography and Tourism, Anhui Normal University
Key Laboratory of Earth Surface Processes and Regional Response in the Yangtze-Huaihe Basin

在全球“碳中和”背景下，土壤碳积累与转化研究成为学术界研究的热点问题。潜水影响下的采煤塌陷地复垦恢复过程中土壤碳库变化及机制较为复杂。复垦土壤碳动力学过程研究是实现复垦土壤生态系统科学恢复的重要基础。利用年龄时间序列方法和定位监测法分别于2012年和2020年采集徐州柳新镇高潜水位煤矿区塌陷地不同复垦年限的土壤，对土壤总碳(CTC)、总有机碳(CTOC)、总无机碳质量分数(CTIC)，总碳库(STC)、总有机碳库(STOC)和总无机碳库储量(STIC)进行了测算，同时分析了各类碳与相关土壤性质的关系。结果表明：① 研究区未塌陷地土壤(CK)STC、STOC和STIC分别为268.34、81.63、186.70 t/hm2。土地塌陷引起土壤碳质量分数及碳库储量下降，主要表现为STIC和CTC下降，STOC变化不明显。② 复垦土壤恢复过程中土壤碳质量分数及碳库储量变化呈正二次方程曲线特征，0～20 cm层土壤CTC和CTIC在复垦14～18 a达到最大，并超过CK。土壤STOC在复垦13～14 a可以超过CK。③ 新复垦土壤0～40 cm层内碳质量分数及碳库储量在上下层次间差异不显著。复垦后恢复过程中，以表层(0～10 cm)土壤碳质量分数和碳库储量增加量最大，CTIC在剖面上的变化特征不明显。④ 土壤CTOC和STOC及CTC均与土壤孔隙度、土壤黏粒、分形维数(D)及 > 3.2 mm团聚体质量分数呈显著正相关，与土壤密度、紧实度、pH及2～0.50 mm团聚体质量分数呈负相关关系。塌陷地复垦土壤在恢复过程中表现出巨大的固碳潜力。高潜水位地区，土壤水分通过影响土壤通气状况、团聚体形成及颗粒变化来影响复垦土壤碳固定和转化。塌陷地复垦耕作利用通过土壤翻耕、破碎、有机肥配施及潜水位调节，改善了土壤结构及通气状况，促进了植物及土壤微生物生长，增加了土壤有机碳来源，推动了复垦土壤有机碳积累。

Under the background of global carbon neutrality, soil carbon accumulation and transformation become a hot topic in academic circles. In the process of land reclamation and restoration, the change and its mechanism of soil carbon pool in coal mining subsidence area under the influence of groundwater are complicated. The study of carbon dynamics in reclaimed soil is an important basis for a scientific restoration of reclaimed soil ecosystem. In this study, the age chronosequense approach and the location-monitoring method were used to study the change of soil carbon pool after the reclamation of coal mining subsidence area in the area with higher level of underground water. Soil samples from the study areas were collected twice, respectively in 2012 and 2020. The content of soil total carbon (CTC, total organic carbon (CTOC), total inorganic carbon (CTIC) were measured, and soil carbon storage of TC pool (STC), TOC pool (STOC), TIC pool (STIC) and rates of carbon sequestration were calculated. The soil properties (i.e., soil bulk density, compaction, porosity and soil structure, etc.) associated with the change of soil carbon were also analyzed simultaneously. The results show that: ① the STC, STOC and STIC of soil in non-subsidence area (CK) were 268.34, 81.63, 186.70 t/hm2 respectively. Land subsidence caused the decrease of STC and STIC, but with no significant change of STOC. ② A quadratic equation curve was shown in the change of soil carbon density and carbon storage in the restoration process of reclaimed soil, the CTC and CTIC of 0−20 cm layer reaching the maximum in 14−18 years after reclamation, and exceeding CK. The STOC could exceed CK in 13−14 years of reclamation. ③ There was no significant difference in carbon density and carbon pool between layers in 0−40 cm of newly reclaimed soil. In the process of restoration after reclamation, the largest increase of carbon density and carbon storage was found in the surface layer (0−10 cm), and there was no regular variation of soil CTIC in the profile for study. ④ The soil CTOC, STOC and CTC were positively correlated with soil porosity, soil clay, fractal dimension (D) and content of aggregate larger than 3.2 mm, but negatively correlated with bulk density, compactness, pH and aggregate content of 2−0.50 mm. There was great potential for carbon sequestration in the reclaimed soil. Soil moisture affected the carbon fixation and transformation of reclaimed soil by influencing soil aeration, aggregate formation and particle change in the area with higher level of underground water. The cultivation could improve soil structure and ventilation condition, promote the growth of plants and soil microorganisms, increase the source of soil organic carbon, and promote the accumulation of reclaimed soil organic carbon by ploughing, crushing, applying organic fertilizer and water level adjustment.

国家自然科学基金资助项目(41101529，42271060)；安徽省教育厅科研资助项目(YJS20210183)

余健，房莉，方凤满，等. 徐州高潜水位区采煤塌陷地及其复垦土壤碳变化[J]. 煤炭学报，2023，48(7)：2881−2892.

YU Jian，FANG Li，FANG Fengman，et al. Change of carbon of reclamation soil in coal mining subsidence areas with high groundwater in Xuzhou[J]. Journal of China Coal Society，2023，48(7)：2881−2892.