Abstract The quantification of soil carbon pools is a pressing topic both for the agriculture productivity and to evaluate the Greenhouse Gases (GHG) sequestration potential, therefore a rapid and precise analytical protocol for carbon speciation is needed. Temperature-dependent differentiation of soil carbon in compliance with the DIN (German Institute for Standardization) 19539 standard has been applied for the first time on 24 agricultural soil samples from the Po River Plain (Italy), with the aim of investigate their thermal behavior in the 50−900 °C interval. The results invariably show the existence of three soil carbon pools having different thermal stabilities, namely, thermally labile organic carbon (TOC400), residual oxidizable carbon (ROC) and total inorganic carbon (TIC900), in the intervals of 300−400 °C, 510−600 °C and 700−900 °C, respectively. Significant relationships have been observed between the above mentioned organic and inorganic carbon pools and the associated isotopic composition: 1) inverse correlation between TOC400/ROC and δ13C links thermal stability and soil organic matter (SOM) composition; 2) direct correlation between carbonate breakdown temperature and δ13C denotes the mineralogical association of the inorganic pool. The results give clues regarding the nature and evolution of soil carbon pools.

中文翻译：

---

土壤碳库的热稳定性：对土壤性质和演化的推论

摘要 土壤碳库的量化是农业生产力和评估温室气体（GHG）封存潜力的紧迫课题，因此需要一种快速而精确的碳形态分析方案。符合 DIN（德国标准化研究所）19539 标准的土壤碳的温度依赖性分化已首次应用于来自波河平原（意大利）的 24 个农业土壤样品，目的是研究它们在土壤中的热行为。 50−900 °C 区间。结果一致表明，在300-400°C的区间内，存在热不稳定有机碳（TOC400）、残留可氧化碳（ROC）和总无机碳（TIC900）三种不同热稳定性的土壤碳库， 510−600 °C 和 700−900 °C，分别。已经观察到上述有机和无机碳库与相关同位素组成之间存在显着关系：1) TOC400/ROC 和 δ13C 之间的负相关联系热稳定性和土壤有机质 (SOM) 组成；2) 碳酸盐分解温度与δ13C 之间的直接相关性表示无机池的矿物学关联。结果为土壤碳库的性质和演化提供了线索。2) 碳酸盐分解温度与δ13C 之间的直接相关性表示无机池的矿物学关联。结果为土壤碳库的性质和演化提供了线索。2) 碳酸盐分解温度与δ13C 之间的直接相关性表示无机池的矿物学关联。结果为土壤碳库的性质和演化提供了线索。