depth, permeability, biological activity, capacity to store water and nutrients, and the amount of organic matter contained in the soil. Soils are living, dynamic systems that are the interface between agriculture and the environment. High-quality soils promote the growth of crops and make farming systems more productive. High-quality soils also prevent water pollution by resisting erosion, absorbing and partitioning rainfall, and degrading or immobilizing agricultural chemicals, wastes, or other potential pollutants. The quality of some U.S. soils, however, is degenerating because of erosion, compaction, salinization, loss of biological activity, and other factors. The full extent of soil degradation in the United States is unknown, but current estimates of damage from erosion understate the true extent of soil degradation.
The 1990 Clean Air Act (PL 101-549) and the Clean Water Act (PL 100-104) give national recognition to the fundamental importance of air and water resources. Soil resources are equally important components of environmental quality, and national policies to protect soil resources