盐土和碱土土壤无机CO2通量的分离

Differentiating the soil inorganic CO_2 flux of saline and alkaline soils

干旱区盐碱土无机CO_2通量是一个崭新、独特的科学现象,打破了土壤CO_2通量完全来自于有机源的假设;然而,盐碱土无机CO_2通量在土壤CO_2通量和全球碳循环中的重要性还缺乏分离和量化的依据,因而存在很大的不确定性。通过采用高压灭菌的方法,将盐土和碱土的土壤无机CO_2通量从土壤CO_2通量中分离。结果表明:高压灭菌方法并不改变土壤的理化性质,并通过土壤有机CO_2通量与温度的关系验证了分离方法的有效性,从而为盐碱土无机CO_2通量的分离、量化和评估提供了一个可靠有效的方法。盐碱土的土壤无机CO_2通量是土壤CO_2通量的重要组分,土壤无机CO_2通量的分离对精确解析干旱区盐碱土生态系统的碳循环是必要的;对盐碱土土壤无机CO_2通量的研究,将促进对干旱区盐碱土土壤CO_2通量和全球碳循环的理解。

The soil inorganic CO~ flux in saline/alkaline soil of the arid land is a unique and brand-new phenome- non, which breaks the assumption that soil CO2 fluxes are purely organic in origin. However, due to lack differentia- tion standard and quantitative data, the significance of soil inorganic CO2 flux to soil CO2 flux and global carbon cy- cle is still uncertainty. The experiment was carried out from August to October in 2009 at the Fukang Station of Des- err Ecology. To determine the potential contribution of soil inorganic CO2 flux to total soil CO2 flux, the soil inorganic CO2 flux was differentiated by sterilization treatment （ 121℃ , 24 h） with pressure steam chamber. The results showed that soil properties had little change before and after sterilization treatment. Having its differentiation effect validated by the relationship between soil organic CO2 flux and temperature, it showed that the sterilization was a re- liable and valid method to differentiate soil inorganic CO2 flux. The effect of soil inorganic COs flux was larger than that of soil organic COs flux, which could dominate the saline/alkaline soil CO2 flux both in direction and magnitude. As a significant component of soil COs flux in saline/alkaline soil, the differentiation and quantification of soil inor- ganic COs flux are necessary to advance understanding of carbon cycle in arid land. Therefore, the non-negligible role of soil inorganic CO2 flux as potential contribution to the arid land ecosystem carbon cycle requires further inves- tigation towards a better understanding of arid land soil CO2 flux and global soil carbon cycle.