不同电导率盐碱土壤固碳潜力

采集内蒙古河套灌区盐碱土壤(电导率EC为0.27mS/cm),利用NaCl调节土壤电导率为(0,10,20,40,80mS/cm),基于稳定碳同位素分析不同电导率土壤添加定量δ¹³C-CO₂后,土壤CO₂吸收量以及土壤难溶性无机碳含量(SIC)-δ¹³C值.结果表明,盐碱土壤能够吸收CO₂,随土壤电导率(EC)升高,土壤CO₂累积吸收量增加, S5(EC=80mS/cm) CO₂累积吸收量比S1(0.27mS/cm)高1.6640mg.土壤SIC含量(R²=0.7080,P<0.05)和土壤可溶性无机碳含量(DIC)(R²=0.6096,P<0.05)与土壤EC显著负相关关系.盐碱土壤吸收CO₂部分固存于土壤无机碳中,外源添加δ¹³C-CO₂,盐碱土壤SIC-δ¹³C值(-5.299‰ ~ -0.8341‰)显著增加.EC为20mS/cm土壤固相保存δ¹³C-CO₂总量最高1.276mg,固存δ¹³C-CO₂总量占土壤吸收¹³CO₂总量比例30.28%最高;EC为80mS/cm固碳量最低为0.2749mg,固存δ¹³C-CO₂总量占土壤吸收¹³CO₂总量比例5.579%.

Potential for fixing inorganic carbon in soils with different salinity levels

The saline-alkali soil (EC=0.27mS/cm) in hetao irrigation area of Inner Mongolia was collected, and the soil conductivity was adjusted by NaCl to (0,10,20,40,80mS/cm). Based on stable carbon isotope, the soil CO₂ uptake and insoluble inorganic carbon content (SI) of soils with different conductivity were analyzed after adding quantitative δ¹³C-CO₂) - the delta ¹³C values. The results showed that salinic-alkali soil could absorb CO₂, and the cumulative CO₂ uptake increased with the increase of soil conductivity (EC). The cumulative CO₂ uptake of S5(EC=80mS/cm) was 1.6640mg higher than that of S1(0.27ms /cm). Soil SIC content (R²=0.7080,P<0.05) and soil soluble inorganic carbon content (DIC)(R²=0.6096,P<0.05) were significantly negatively correlated with soil EC. The value of SIC-d¹³C (-5.299‰~-0.8341‰) in saline-alkali soil increased significantly with the addition of d¹³C-CO₂. In EC, the highest d¹³C-CO₂ concentration was 1.276mg in 20mS/cm soil, and the highest δ¹³C-CO₂ concentration was 30.28% in soil ¹³CO₂ absorption. When EC was 80mS/cm, the lowest carbon sequestration was 0.2749mg, and the total d¹³C-CO₂ sequestration accounted for 5.579% of the total ¹³CO₂ sequestration.