Origins of Major N Compounds Identified

As to the origins of the major N compounds identified, it is possible that at least a portion of some of these compounds are pyrolysis products of amino acids, peptides, proteins, [18] and porphyrins (a component of chlorophyll), [19] or originate from the microbial decomposition of plant lignins and other phenolics in the presence of ammonia. [20] Of considerable interest are the identifications aromatic and aliphatic nitriles. Nitriles can be formed from amines with the loss of 2 H2, from amides with the loss of H20, and also by reacting n-alkanoic acid with NH3. [21] The detection of long-chain alkyl- and dialkyl-nitriles points to the presence in the soil or SOM of long-chain amines 

Further research is needed to identify additional N-heterocyclics in soils and to determine whether the N-heterocydics are present in the soil in the forms in which they were identified or whether they originate from more complex structures. If the latter is the case, we need to isolate these complex N-containing molecules and attempt to identify them. 

In contrast to the finding by 1SN NMR that 85 % of the total soil N occurs in proteins or peptides, chemical methods show that only about 40 % of the total soil N occurs in proteins. [4] What are the reasons for these wide divergencies To provide answers to these questions, it may be useful to consider the following  

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