• 关键词：外源盐  无机碳  土柱淋溶  运移转化  盐碱土壤

• 基金项目：国家自然科学基金（No.41865010，41675140）；2019年内蒙古自治区高等学校青年科技英才领军人才项目（No.NJYT-20-A04）；第十批内蒙古自治区草原英才项目（2020）；2016内蒙古自治区青年创新人才计划项目

• 于俊霞
• 内蒙古师范大学化学与环境科学学院, 内蒙古自治区环境化学重点实验室, 呼和浩特 010022

• 焦燕
• 内蒙古师范大学化学与环境科学学院, 内蒙古自治区环境化学重点实验室, 呼和浩特 010022

• 杨文柱
• 内蒙古师范大学化学与环境科学学院, 内蒙古自治区环境化学重点实验室, 呼和浩特 010022

• 刘立家
• 内蒙古师范大学化学与环境科学学院, 内蒙古自治区环境化学重点实验室, 呼和浩特 010022

• 宋春妮
• 内蒙古师范大学化学与环境科学学院, 内蒙古自治区环境化学重点实验室, 呼和浩特 010022

• 于亚泽
• 内蒙古师范大学化学与环境科学学院, 内蒙古自治区环境化学重点实验室, 呼和浩特 010022

• 摘要：为探究干旱盐碱区高风化土壤-地下水无机碳的固存机制，利用室内土柱淋溶模拟实验结合相关与回归分析，设置5个土壤电导率（EC=0.899、10、20、40、80 mS·cm^-1）处理，依次编号为S₀、S₁、S₂、S₃、S₄，每个处理重复2次，共计10个土柱（内径7.5 cm，高120 cm），研究无机碳在不同盐碱程度土壤及淋出液中的分布、运移转化及其影响因素.结果表明：①土壤及淋出液无机碳含量均随土壤电导率的增加呈先增后降的变化趋势，其中，淋出液溶解性无机碳（DIC）和土壤难溶性无机碳（SIC）含量在电导率为10 mS·cm^-1处理下最高（淋溶后分别可达431.58 mg·L^-1和128.91 g·kg^-1），且该处理下淋出液DIC含量随淋溶时间延长持续增加；土壤可溶性无机碳（SDIC）含量在电导率为20 mS·cm^-1处理下高于其他处理，在表层（0~30 cm）有最高值（淋溶后可达0.66 g·kg^-1），随深度增加而降低.电导率为0~20 mS·cm^-1处理下，表层土壤SIC含量低于深层（60~100 cm）土壤；电导率为40和80 mS·cm^-1处理下，土壤及淋出液无机碳含量均降低，土壤SIC在表层聚积，随深度增加而降低.②淋出液DIC与EC呈显著负相关（r=-0.928，p<0.01），与pH呈显著正相关（r=0.958，p<0.01）；土壤SDIC与土壤EC呈显著负相关（r=-0.582，p<0.05），与土壤pH呈显著正相关（r=0.899，p<0.01）；土壤SIC与土壤EC呈显著负相关（r=-0.58，p<0.05），与土壤pH无明显相关性（r=0.236，p>0.05）.pH和EC都是影响土壤及淋出液中无机碳含量的重要因素，pH对溶解性无机碳的影响高于EC，土壤难溶性无机碳主要受EC影响.总而言之，在干旱盐碱区高风化土壤的淋溶过程中，无机碳一部分以DIC的形式随淋溶液淋出到地下水中，另一部分以SDIC和SIC的形式存在于土壤中.

• Abstract：To investigate the sequestration mechanism of inorganic carbon in highly weathered soil-groundwater system in arid saline-alkali area, we conducted soil column leaching experiments with five soils of different electrical conductivity (EC) treatments (0.899, 10, 20, 40, 80 mS·cm^-1, S₀~S₄). Each treatment was repeated twice and 10 soil columns (inner radium 7.5 cm, height 120 cm) were used. The distribution, migration and transformation of inorganic carbon in soil and leaching solution of different salinity and potential influencing factors were deeply explored. The results showed that:①inorganic carbon in soil and leaching solution first increased with soil conductance, and then decreased. After leaching, dissolved inorganic carbon (DIC) in leaching solutions and insoluble inorganic carbon (SIC) in soils in treatments of 10 mS·cm^-1 were the highest (431.58 mg·L^-1 and 128.91 g·kg^-1, respectively), and the DIC in leaching solution increased continuously with leaching. After leaching, dissolved inorganic carbon in soil (SDIC) of 0~30 cm surface layer was the highest(0.66 g·kg^-1) in treatments of 20 mS·cm^-1, and decreased with soil depth increasing. In the treatments of 0~20 mS·cm^-1, SIC accumulated in deep soil (60~100 cm). In the treatments of 40 and 80 mS·cm^-1, inorganic carbon in soil and leaching solution decreased, and SIC enriched in 0~30 cm surface layer.②Correlation analysis showed a significant negative correlation (r=-0.928, p<0.01) between DIC and EC, a significant positive correlation between DIC and pH (r=0.958, p<0.01), a negative correlation (r=-0.582, p<0.05) between soil SDIC and EC, a significant positive correlation between SDIC and soil pH (r=0.899, p<0.01), a negative correlation (r=-0.58, p<0.05) between soil SIC and EC and no obvious correlation between soil SIC and pH (r=0.236, p>0.05). pH and EC are important factors affecting inorganic carbon in soil and leaching solution, and the former was more important; however, soil insoluble inorganic carbon was mainly controlled by EC. Therefore, in the leaching process of highly weathered soil in arid saline-alkali area, some inorganic carbon leached into groundwater with leaching solution in the form of DIC, the others remained in the soil in the form of SDIC and SIC.

• Key words：exogenous salt  inorganic carbon  soil column leaching  migration and transformation  saline-alkali soil

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