Humic materials nitrogen compounds

Identification of N-, P-, and S-containing compounds is difficult, and those that are identified tend to be metabolic products, such as nucleotides and vitamins, released into the soil following the death of cells. Broadly, nitrogen is an integral part of the humic molecule, and is released as NH4 ions when the humic material is degraded. Phosphorus and sulfur are more commonly found as P and S esters, which can be released as orthophosphate and sulfate ions by the action of phosphatase and sulfatase enzymes, respectively. 

In solution NMR, the spin lattice relaxation Tin of small molecules can vary from seconds to hours.(66) Thus this contributes to even more serious sensitivity problems when one considers the need to wait 4-5 Tin between pulses. In a recent study of the relaxation behavior of nitrogen containing organic material in NaOH-extracts of plant composts with an incubation time up to 541 days, it was found that the extracted compounds behave in a similar manner to biomacro-molecules.(6i,66,75) At a resonance frequency of 30.4 MHz, the Tin s of humic substances derived from degrading plant material range from 1 to 3 s.(6i)... 

Organic materials undergo microbial enzymatic and chemical reactions in soils to form colloidal polymers called humus (Fig. 6.1). Humus is a complex and rather microbially resistant mixture of brown to almost black, amorphous and colloidal substances modified from the original plant tissues or resynthesized by soil organisms. Humus contains approximately 10% carbohydrates, 10% nitrogen components (proteins, amino acids, and cyclical N compounds), 10% lipids (including alkanes, alkenes, fatty acids, and esters), and 70% humic substances. 

---