People depend upon soils to meet a variety of societal and human needs such as the production of food and fiber. Soils also are important in the hydrologic cycle storing water for plant growth and purifying drinking water by percolation. Humans use soil to stabilize and store human wastes, reducing exposure to disease and other hazards. Even though soils are an important resource they are generally overlooked and their chronic loss and degradation goes unnoticed. Soil is continually being lost by wind and water erosion, or rendered unusable and unproductive by chemical and physical degradation. Rates of soil loss caused by human activities are greater than rates of replacement.