More persistent pesticides that have longer half-lives can pose a greater threat to the environment since they remain there longer. Pesticides are degraded into harmless compounds by sunlight, soil microorganisms and a variety of chemical and physical reactions. The rate of degradation is affected by the physical, chemical and biological characteristics of the pesticide and the associated environment. To maximize pesticide effectiveness and minimize potential environmental concerns, the properties of the pesticide must be compatible with the physical, chemical and biological conditions of the application site. Together, these four factors determine how a pesticide should be applied and influence its ultimate environmental fate.
Texture is the percent of sand, silt and clay in soil.
The rate that water moves through soil, or its permeability, is affected by texture. Sandy soils are usually highly permeable because they are coarse textured, or composed mainly of large particles. In general, the sandier the soil, the higher the permeability. Soils high in clay and silt, on the other hand, are fine textured. They are composed mainly of small particles that generally have only tiny gaps for water movement.