Both plants and animals help to create a soil. As they die, organic matter incorporates with the weathered parent material and becomes part of the soil. Living animals such as moles, earthworms, bacteria, fungi and nematodes are all busy moving through or digesting food found in the soil. All of these actions mix and enrich the soil. Topography Topography is the hilliness, flatness, or amount of slope of the land.
Soils vary with topography primarily because of the influence of moisture and erosion.
In many areas, moist, poorly drained soils are located in low areas, and depressions of the land. In contract, soils in sloping areas can be drier and well drained. These soils tend to be moderately and well developed. Erosion can remove all or part of the topsoil and subsoil, leaving weakly developed soil. Time It may take hundreds of years to form one inch of soil from parent material.