In undisturbed soil, most nutrient cycling, roots and biological activity are found in the top 20 to 30 centimetres. This is called the rhizosphere or rooting zone. The rooting zone is the root, soil attached to the root and the adjacent soil influenced by the root. On the Prairies, the most action probably occurs in the top five cm of topsoil. Every plant has a unique rooting system and leaves behind an individual signature in the form of carbon.
Carbon is the most important element in soil.
Everything that lives near the roots depends on carbon. If something upsets the balance, it is war among the organisms as each fights to survive. This affects plant growth and productivity. Soil that smells like rotten eggs means there is not enough carbon and too much anaerobic activity happening. Crops with more roots provide a larger area for soil microbes to colonize and add more organic matter to the soil.