ABSTRACT
This chapter considers the interrelationships among soil organic matter, carbon and nitrogen transformations as influenced by temperature and water, and tillage and residue management in the rhizosphere of mineral soils. Agricultural production systems that control and manage soil organic matter levels can directly influence the environment and ecology of the rhizosphere. Amounts and distribution of soil organic matter are regulated by the so-called "factors of soil formation," that is, time, climate, vegetation, parent material, and topography. Tillage, through its impact on soil structure, significantly affects water and heat transfer in the soil and gaseous exchange with the atmosphere. Abandonment of conventional tillage for a reduced or no-tillage system results in a concentration of roots near the soil surface. The relationship between soil tillage and management of crop residues, as mediated through soil organic matter, is seen as a direct influence on plant root development and the rhizosphere environment.
