Soil organic carbon forcing

Figure 5.1. Fluxes of C in and out of soil and their forcing factors (SOC, soil organic carbon SIC, soil inorganic carbon NPP, net primary production).

Since sorption is primarily a surface phenomenon, its activity is a direct function of the surface area of the solid as well as the electrical forces active on that surface. Most organic chemicals are nonionic and therefore associate more readily with organic rather than with mineral particles in soils. Dispersed organic carbon found in soils has a very high surface-to-volume ratio. A small percentage of organic carbon can have a larger adsorptive capacity than the total of the mineral components. 

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. 

Schnitzer M, Khan SU (1978) Soil organic matter. Elsevier, New York, 319 pp Schultz RB (1991) Metalliferous black shales accumulation of carbon and metals in cratonic basins. In Force ER, Eidel JJ, Maynard JB (eds) Sedimentary and diagenetic mineral deposits a basin analysis approach to exploration. Society of Economic Geologists, El Paso, TX. Rev Econ Geol 5 171-176 Seewald JS, Seyfried WE (1991) Experimental determination of portlandite solubility in H2O and acetate solutions at 100-350 °C and 500 bars constraints on calcium hydroxide and calcium acetate complex stability. Geochim Cosmochim Acta 55 659-669... 

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