Biological transformation of organic matter in soil is a crucial factor affecting the global carbon cycle. In order to understand these complex processes, soils must be investigated by a combination of various methods. This study compares the dynamics of biological mineralization of soil organic matter (SOM) determined via CO2 evolution during an 80-day laboratory incubation with their thermo-oxidative stability determined by thermogravimetry (TG). Thirty-three soil samples, originating from a wide range of geological and vegetation conditions from various German national parks were studied. The results showed a correlation between the amount and rate of respired CO2 and thermal mass losses of air-dried, conditioned soils occurring around 100 °C with linear coefficients of determination up to R2 = 0.85. Further, correlation of soil respiration with thermal mass losses around 260 °C confirmed previous observations. The comparison of TG profiles from incubated and non-incubated soils underlined the importance of thermal mass losses in these two temperature intervals. Incubated soils had reduced thermal mass losses above 240 °C and conversely an increased mass loss at 100–120 °C. Furthermore, the accurate determination of soil properties by TG such as soil organic carbon content was confirmed, and it was shown that it can be applied to a wider range of carbon contents as was previously thought. It was concluded that results of thermal analysis could be a helpful starting point for estimation of soil respiration and for development of methods revealing processes in soils.
1. Bastida, F, Zsolnay, A, Hernández, T, García, C2008Past, present and future of soil quality indices: a biological perspective. Geoderma147:159–171.
Zhang, L, LeBoeuf, E, Xing, B2007Thermal analytical investigation of biopolymers and humic- and carbonaceous-based soil and sediment organic matter. Environ Sci Technol41:4888–489410.1021/es063106o.)| false
12. Gaál, F, Szöllösy, I, Arnold, M, Paulik, F1994Determination of the organic matter, metal carbonate and mobile water in soils. Simultaneous TG, DTG, DTA and EGA techniques. J Therm Anal Cal42:1007–1016.
Gaál, F, Szöllösy, I, Arnold, M, Paulik, F1994Determination of the organic matter, metal carbonate and mobile water in soils. Simultaneous TG, DTG, DTA and EGA techniques. J Therm Anal Cal42:1007–101610.1007/BF02547123.)| false
Plante, AF, Fernández, JM, Haddix, ML, Steinweg, JM, Conant, RT2011Biological, chemical and thermal indices of soil organic matter stability in four grassland soils. Soil Biol Biochem43:1051–105810.1016/j.soilbio.2011.01.024.)| false
18. UrenNC. Types, amounts, and possible functions of compounds released into the rhizosphere by soil-grown plants. In Pinton et al., editors. The rhizosphere: biochemistry and organic substances at the soil-plant interface. Taylor and Francis group; 2007. p. 23–72.
UrenNC. Types, amounts, and possible functions of compounds released into the rhizosphere by soil-grown plants. In Pinton et al., editors. The rhizosphere: biochemistry and organic substances at the soil-plant interface. Taylor and Francis group; 2007. p. 23–72.)| false
Plante, AF, Pernes, M, Chenu, C2005Changes in clay-associated organic matter quality in a C depletion sequence as measured by differential thermal analyses. Geoderma129:186–19910.1016/j.geoderma.2004.12.043.)| false
Jaeger, F, Grohmann, E, Schaumann, GE20061H NMR relaxometry in natural humous soil samples: insight in microbial effects on relaxation time distributions. Plant Soil280:209–22210.1007/s11104-005-3035-4.)| false