ABSTRACT
This chapter describes the awareness of the soil inorganic carbon (SIC) pool in soil. Most soil organic carbon (SOC) is the product of photosynthesis, driven by solar energy, in the chloroplasts of higher plants, algae and some bacteria including the cyanobacteria and lichens. There are three main types of SIC: lithogenic carbonates derived directly from parent calcareous geology, biogenic carbonates formed by organisms and pedogenic carbonates formed by dissolution. The mean residence time of soil carbon (C) is modulated by a complex and interacting set of biotic and abiotic processes all of which are likely to be affected by climate change to some extent. Physical protection of SOC is recognized as a dominant control on longer-term residence times of SOC at the decadal-to-millennial scale. The classical DLVO theory (Derjaguin, Landau, Verwey, and Overbeek) assumes soil colloids have flat surfaces, but recently Bradford et al. have proposed that for rough and irregular colloid surfaces.
