Stabilization of Soil Organic Matter

Mikutta, R., Kleber, M.,Torn, M. S., and Jahn, R. (2006). Stabilization of soil organic matter association with minerals or chemical recalcitrance Biogeochem. 77, 25-56. 

Soil minerals play a stabilizing role in organic matter. The Al and Fe that complex and stabilize organic matter against microbial decomposition are released from soil minerals during soil formation. The supply rates apparently control the content of soil organic matter to a great extent. This is demonstrated by the relationship between pyrophosphate-extractable C and pyrophosphate-extractable Al plus Fe (Wada 1995). 

Sollins P, Homann P, Caldwell BA (1996) Stabilization and destabilization of soil organic matter mechanisms and controls. Geoderma 74 65-105... 

Wolters, V. (2000). Invertebrate control of soil organic matter stability. Biol. Fertil Soils, 31, 1-19. 

Kalbitz, K., Schwesig, D., Rethemeyer, J., and Matzner, E. (2005). Stabilization of dissolved organic matter by sorption to the mineral soil. Soil Biol. Biochem. 37,1319-1331. 

Six, J., Conant, R. T., Paul, E. A., and Paustian, K. (2002). Stabilization mechanism of soil organic matter Implications for C-saturation of soils. Plant Soil 241,155-176. 

Figure 14.8. Thermograms for the volatilization of peptide-derived compounds in freeze-dried rhizodeposits leached from a soil cropped with maize after a daytime and a nighttime growth period and thermogram for the volatilization of L-glutamic acid. Reprinted from Leinweber, P., Jandl, G., Baum, C., Eckhardt, K.-U., and Kandeler, E. (2008). Stability and composition of soil organic matter control respiration and soil enzyme activities. Soil Biology and Biochemistry 40,1496-1505, with permission from Elsevier.

Pefferkorn E. Structure and stability of natural organic matter/soil complexes and related synthetic and mixed analogues. Adv Colloid Interface Sci 1997 73 127-200. 

The increase in atmospheric COi because of fossil fuel emissions has been identified as a major driving force for global climate change. Soil organic matter (SOM) is expected to be an important sink for this carbon (Ciais et ciL, 1995 Schimel, 1995 Steffen et aL, 1998). However, at higher mean temperatures, this sink may act as additional source for CO2 if it is accessible to microbial decomposition. To understand these complex interactions between stabilization and decomposition of SOM, it is crucial to investigate not only the turnover and stability, but also the chemical nature of soil organic matter. 

Stabilization mechanisms of soil organic matter implications for C-saturation of soils. Plant and Soil 241,155-1 76. 

The resistance of soil organic matter to biological decomposition under natural conditions has long been known but probably somewhat underestimated until the advent of C dating. Results obtained recently by this technique show quantitatively the age of soil carbon, and by selection of samples and their fractionation the technique can be used to throw light on the reasons for the stability. 

The stability, or resistance of soil organic matter to biological and chemical attack, constitutes one of its most important and puzzling characteristics. In the numerous chemical studies that have been conducted it is common for only 20—50% of the organic C and N substances to be released as comparatively simple compounds that can be identified. The percentage of the C and N that is apparently bound up in complexes is dependent to some extent on the organic matter itself (proportion of humic and non-humic materials), and even more on the methods used to fractionate the organic matter, and to separate it from colloidal clay. 

For stabilization of heavy metals at contaminated sites, the unavoidable biogeochemistry of soil organic matter and particularly humic substances (HS), not just their static properties, in relation to heavy metal binding is critically inq)ortant for long-term sustainability. Yet this fiictor is poorly understood at the moleculm level Soil widi... 

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