Organic Soil Substances

the complex of the organic compounds that make up soil.

The presence of organic soil substances is one of the main criteria that distinguishes soil from its parent rock. Organic soil substances are formed in the process of decomposition of plant and animal matter and are the most important link in the cycle of matter. The quantity and nature of organic soil substances largely determine the direction of the process of soil formation. They also determine the biological, physical, and chemical properties of the soil and the fertility of the soil. Organic soil substances contain plant and animal residues in varying quantities and extents of decomposition, always with the predominance of humic substances.