Increases Soil Permeability

Infiltration is the movement of water into soil from the surface. The infiltration rate is the rate at which water will enter a soil under specified conditions. Infiltration rate is usually expressed as centimeters per hour. Water infiltration is largely governed by the surface properties of the soil. A soil high in organic matter, having good structure, and of medium to coarse texture will usually have a rapid infiltration rate. Many other factors, such as roughness of the ground surface, vegetative cover, and slope, will also affect infiltration. Water movement within soil also affects infiltration. Water already in the soil profile must move downward before more water can enter at the surface.

The ease with which water moves within a soil is termed permeability or hydraulic conductivity. Permeable soils conduct water readily through their mass. Other soils may conduct water slowly or have restricting layers or horizons which limit or prevent downward movement of water. Soils or soil layers which do not conduct water, at all, are termed impermeable. Permeability, like infiltration, is largely determined by texture, structure, and organic matter content. Other factors, such as the dominant ion on the exchange complex, presence of chemical cementing agents, and type of clay minerals present, also influence permeability.