Some Problems in soil Taxonomy
Distinction between Soil layer and Soil Horizon
First of all we have to consider in our mind that all the soil layers and soil horizons are the result of the interaction affect of 3 external geological processes ( Weathering, Erosion and Deposition ) , six soil forming factors(Climofactor, Biofactor , Anthropofactor, Topofactor , Lithofactor and Chronofactor ) and 29 pedogensis processes (Soil forming presses).
Secondly Soil layer is an earthy pedogenic plain continuous and parallel to soil surface ,characterized by only a morphological features distinguishing it from other layers , While the soil horizon is an one layer or more pedogenic continuous and parallel to soil surface , characterized by both morphological and micromorphological features distinguishing it from other horizons.
Thirdly soil layers can be divided in to the following :
1- Organic soil layers (formed by only a soil forming processes)
2- Mineral soil layers (formed by external geological processes, soil forming factors and soil forming processes).
3- Transitional mineral soil layers (formed by external geological processes, soil forming factors and soil forming processes).
4- Mineral soil layers (formed by only an external geological processes).
So the Soil layers are not the equivalent of the soil horizons ( Diagnostic Horizons of Soil Taxonomy). While designations of soil layers express a qualitative judgment(Color, Structure, Texture, Coarse fragments, motels and hardness) about the kinds of changes that are believed to have taken place in a soil, soil horizons ( diagnostic horizons) are quantitatively defined features that are used to differentiate between taxa. And a diagnostic horizon may encompass several soil layers.
