Humic material/substances formation

Humic materials. The so-called humic substances are probably the most abundant polymers in nature. The standing crop of humic materials in the soil has been estimated to be approximately 2-3 x 10 tons (Bazilevitch, 1974). They are brown, acidic materials which bear no immediately apparent resemblance to conceivable precursor materials, and appear to be formed by oxidation and condensation reactions between polyphenols, polysaccharides, and polyamino acids of plant and microbial origin. As Hurst and Burges (1967) pointed out, This situation is undoubtedly the most complicated and variable existing in nature. Despite nearly two centuries of investigation, environmental chemists still cannot agree on a rational structure for humic substances or on mechanisms for their formation. 

The rate of cadaver decomposition in soil can be affected by how often a particular site is subjected to cadaveric material. Microbial degradation is typically described as having three phases. The initial lag phase is defined by microbial or enzymatic enrichment. During the second phase the substrate is rapidly degraded. This is followed by a declining phase that results from a lack of readily available substrate or formation of humic substances (Ajwa and Tabatabai 1994). Forensic taphonomy holds that the burial of a number of cadavers in soil over time will result in an increased number of soil microorganisms (Janaway 1996). Experiments using controlled burial environment... 

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