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干旱区盐碱土的土壤无机CO_2通量是一个崭新、独特的科学现象,打破了土壤CO_2通量完全来自于生物源的假设。为研究温度对土壤无机CO_2通量的影响,2009年8—10月在阜康荒漠生态系统实验站,以盐土和碱土为研究对象,通过灭菌处理(121℃,24h),将土壤CO_2通量拆分为土壤无机CO_2通量和土壤有机CO_2通量,分析三者的日动态特征及其与温度的相关关系。结果表明,土壤CO_2通量、土壤无机CO_2通量和土壤有机CO_2通量均存在明显的日动态;除碱土的土壤有机CO_2通量日动态呈弱双峰曲线外,盐土和碱土的土壤CO_2通量、土壤有机CO_2通量和土壤无机CO_2通量日过程均呈单峰曲线,表现为日间CO_2通量随温度升高而增加,峰值出现在12:00—14:00,随后随温度降低而减小,谷值出现在3:00—4:00。盐土和碱土的土壤无机CO_2通量作用超过土壤有机CO_2通量,主导土壤CO_2通量的日变化。土壤CO_2通量和土壤无机CO_2通量主要受温度调控,呈直线方程关系。忽略土壤无机CO_2通量对土壤CO_2通量的贡献,将严重低估土壤有机CO_2通量,是造成干旱区碳循环评估不准确的重要因素之一。
The soil inorganic CO_2 flux of saline-alkali soil in arid area is a new and unique scientific phenomenon, which breaks the hypothesis that soil CO_2 flux completely comes from biological sources. In order to study the effect of temperature on soil inorganic CO 2 flux, soil organic carbon dioxide (CO 2) -containing soil was treated by sterilization (121 ℃, 24h) at the Fukang Desert Ecosystem Experimental Station from October to October in 2009. The quantities were divided into inorganic CO 2 fluxes and soil organic CO 2 fluxes, and the daily dynamic characteristics and their correlation with temperature were analyzed. The results showed that soil CO_2 flux, soil inorganic CO_2 flux and soil organic CO_2 flux both had obvious daily dynamic. Soil organic CO_2 flux in diaspore soil was weakly double-peaked curve. Soil CO_2 flux in saline soil and alkaline earth The daily process of soil organic CO 2 flux and soil inorganic CO 2 flux showed a single peak curve, which showed that the CO 2 flux increased with the increase of temperature during the day, the peak appeared at 12: 00-14: 00 and then decreased with the decrease of temperature While decreasing, the trough appears at 3: 00-4: 00. Soil inorganic CO 2 flux in saline soil and alkaline earth exceeded the organic CO 2 flux of soil, and dominated diurnal variation of soil CO 2 flux. Soil CO 2 flux and soil inorganic CO 2 flux were mainly controlled by temperature, showing a linear equation. Neglecting the contribution of soil inorganic CO 2 flux to soil CO 2 flux will seriously underestimate the organic CO 2 flux in soil, which is one of the most important factors contributing to the inaccurate estimation of carbon cycle in arid region.