Soil Physical Characteristics and the Effects on Gully Development. Soil erosion is a naturally occurring process that affects all the land form. In agriculture soil erosion to as the wearing away of the fields top soil by the natural physical forces of water and wind. The activities associated with farming help particularly tillage. Erosion by water and wind involves three distinct actions:soil detachment transportation and deposition. Posen et al (1999) said that the soil erosion can be a slow process that continues relatively unnoticed or can occur at an alarming rate causing serious loss of top soil, soil compaction low organic matter and loss drainage.
Salinisation and soil acidity problems are other serious soil degradation conditions that can accelerate the soil erosion process. The physical characteristics of the soil such as structure of the soil, the permeability of soil the shear strength, colour and soil credibility play major roles in soil erosion and degradation. Soil erodibility is the vulnerability of the soil to erosion and it is one of the erosion process. Texture is one of the character is one of principle soil characteristics affecting erodibility while soil structure, organic matter and permeability also contribute immensely on soli erosion.
Generally soil with an increased infiltration rate, higher levels of organic matter and improved soil structure have greater rsistance to erosion (korener 1957) sand, sandy, loam, and loam, textured soil tend to be less erodible than silt, very fine sand and certain day-textured soil. The slope gradient and the length greater roles in erosion process longer the slope of a field the higher the risk for erosion. Soil erosion by water increases due to the greater accumulation of runoff that more as higher velocity on the surface. Consolidation of small slopes lengths with increased velocity of water with permits a greater degree of scouring (carrying capacity for sediment) all these parameter determine the strength of the soil and their ability to resist detachment and soil flow which may result to gully erosion. The nature of the soil affects both soil detachment, transported and deposition.