SOIL SLOPE/(Catena)?

Question

Does anyone have any good websites on soil slopes or soi catenas or just know any ifformation on them at all?

Answer 1

Soil Catena:

A catena (Latin for `chain') is a sequence of soils down a slope where each facet is different from, but linked to, its adjacent facets. Catenas therefore illustrate the way in which soils can change down a slope where there are no marked changes in climate or parent rock. Each catena is an example of a small-scale, open system involving inputs, processes and outputs. The slope itself is in a delicate state of dynamic equilibrium with the soils and landforms being in a state of flux and when the ratio of erosion and deposition varies between the different slope facets.

Soil Slope:

Slope has a scale connotation. It refers to the ground surface configuration for scales that exceed about 10 meters upward to the landscape as a whole. Slope has gradient, complexity, length, and aspect.

Slope gradient is the inclination of the surface of the soil from the horizontal. It is generally measured with a hand level. The difference in elevation between two points is expressed as a percentage of the distance between those points.

If the difference in elevation is 1 meter over a horizontal distance of 100 meters, slope gradient is 1 percent. A slope of 45 degrees is a slope of 100 percent because at this angle, the difference in elevation between two points 100 meters apart horizontally is 100 meters. Overland flow gradient is the slope of the soil surface in the direction of flow of surface water if it were present.

Slope Complexity refers to surface form on the scale of a mapping unit delineation. In many places internal soil properties are more closely related to the slope complexity than to the gradient. Slope complexity has an important influence on the amount and rate of runoff and on sedimentation associated with runoff as well as cost to excavate and develop.

Terms are provided for both simple and complex slopes in some classes. Complex slopes are groups of slopes that have definite breaks in several different directions and in most cases markedly different slope gradients within the areas delineated.

Slope length has considerable control over runoff and potential accelerated water erosion. Terms such as "long" and "short" can be used to describe slope lengths that are typical of certain kinds of soils. A "long" slope in one place might be "short" in another. If such terms are used, they are defined locally. For observations at a particular point, it may be useful to record the length of the slope that contributes water to the point, in addition to the total length of the slope. The former is called point runoff slope length. The latter, sediment transport slope length, is the distance from the expected or observed initiation upslope of runoff to the highest where deposition of sediment would be expected to occur. This distance may be less than or more than the point runoff slope length.

Slope aspect is the direction toward which the surface of the soil faces. The direction is expressed as an angle between 0 and 360 degrees (measured clockwise from true north) or as a compass point such as east or north-northwest. Where slope aspect is a principal variable, it may affect soil temperature, evapotranspiration, and winds received.