脱硫石膏溶解产生的Ca2+会和土壤中含碳的阴离子(CO32-、HCO3-)发生反应，最终将CO2 吸收并固定为土壤无机碳。脱硫石膏在碱土改良中的无机固碳作用对实现"碳中和"具有重要意义。以新疆阜康三工河流域的荒漠碱土为研究对象，以脱硫石膏为钙源物对0～20 cm土层进行改良。探究不同时间0～40 t·hm-2脱硫石膏施用量下土壤无机碳(SIC)和土壤无机碳密度(SICD)的变化，从而研究碱土改良中的无机固碳作用。结果表明:施用脱硫石膏能显著减轻土壤碱害(pH下降)，增加土壤盐分，同时具有无机固碳作用(SIC和SICD上升)(P<0。05)。脱硫石膏最佳施用量为30 t·hm-2，此时改良土层pH降至最低(8。24)。改良后0～46 d SIC含量相较对照组增加0。93 g·kg-1，SICD增加0。29 kg·m-2(即CO2固定量为1。06 kg·m-2)。改良过程中，脱硫石膏施用量与SIC、SO42-和Ca2+呈显著正相关(P<0。05)，与pH、CO32-、HCO3-和Na+呈显著负相关(P<0。05)。气候因子对土壤无机固碳存在影响，增大相对湿度和降水量会抑制SIC含量和SICD增加，而增大风速、温度和太阳总辐射则有促进作用。研究结果为施用脱硫石膏改良碱土能增加土壤固碳潜力提供了直接证据。
Inorganic Carbon Sequestration Effect of Desulfurized Gypsum in Alkaline Soil Improvement
[Objective]Ca2+ produced by dissolution of desulfurized gypsum will react with carbon-containing anions(CO32-,HCO3-)in the soil,and eventually CO2 is absorbed and fixed as soil inorganic carbon.The inorganic carbon fixation of desulfurized gypsum in alkaline soil improvement is of great significance to achieving"carbon neutrality".[Method]In this study,the 0-20 cm soil layer of desert alkaline soil in the Sangong River basin of Fukang,Xinjiang,was improved by using desulfurized gypsum as a calcium source.The changes in soil inorganic carbon(SIC)and soil inorganic carbon density(SICD)were investigated under different application rates of desulfurized gypsum at different times,so as to study the role of inorganic carbon sequestration in alkaline soil improvement.[Result]The results showed that the application of desulfurized gypsum significantly reduced soil alkali damage(pH decreased)and increased soil salinity and inorganic carbon sequestration effect(SIC and SICD increased)(P<0.05).The optimal application rate of desulfurized gypsum was 30 t·hm-2,when the pH of the improved soil layer was reduced to the lowest(8.24).The SIC increased by 0.93 g·kg-1 and SICD increased by 0.29 kg·m-2(i.e.,CO2 fixation was 1.06 kg·m-2)from 0 to 46 days after the improvement.The amount of desulfurized gypsum application was significantly positively correlated with SIC,SO42-and Ca2+(P<0.05)and negatively correlated with pH,CO32-,HCO3-and Na+(P<0.05)during the improvement process.Climatic factors had an effect on soil inorganic carbon sequestration;increasing relative humidity and precipitation suppressed the increase in SIC and SICD,while increasing wind speed,temperature and total solar radiation facilitated it.[Conclusion]The results of this study provide direct evidence that the application of desulfurized gypsum to improve alkaline soils will increase the carbon sequestration potential of the soils.
万方数据
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