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. Only the top few inches are productive in the sense of being able to sustain plant growth. This is why soil conservation is so important. The result of all of these forces is soil that develops into layers known as horizons . The first or top 48 inches of these horizons and its' unique set of characteristic is used by soil scientist to classify and name a soil.