The one element required in large amounts by organisms is Carbon. Carbon is taken up by the plant as carbon dioxide, a compound found in the atmosphere in very low levels, and thus is often one of most limiting factors in foliage development. It is taken in by plants for the manufacture of carbohydrates, proteins, and oils. When too much Nitrogen is applied to the soil, it induces a carbohydrate deficiency which in turn reduces bacterial populations.
Most microbial forms oxidize organic carbons as a source of nutrition.
Nitrogen is used by plants to synthesize amino acids which in turn form proteins, which are part of the protoplasm of all living cells. Nitrogen is also required by plants for utilizing other vital compounds such as chlorophyll, nucleic acids, and enzymes. Elemental nutrients, because of the nature of the electrical charges of their molecular makeup, can have a dramatic affect on plant health. Micro-organisms can alter these compounds to allow ready availability. It is also used in the storage and transfer of energy.