Soil classification refers to the grouping or organization of soil into classes according to their general characteristics. Soil are classified into two levels which are local level based on the dominant soil soil formation factors like parent rock, micro climate, vegetation, slope and drainage and global level, based on factors like climate, water and vegetation, which are dominant in the soil profile development. Their interplay produces varying soil regimes.Lateritization, calcification, podzolization and salinization are the main soil profile forming processes under different climates.
Criteria for soil classification:
There are number of factors /criteria used in classifying soils. Some of the criteria used include the following;
- Climatic variation in which soil can be classified as soil of humid tropics(like laterites) ir soils of cold regions like tundra soils
- Morphological properties of soil like depth, color, texture, structure, temperature, water content, organic matter composition and chemical composition
- Genesis (origin or mode of formation), based on soil forming processes such as gleization that produce peat, podzolisation that produce podzol and so forth.
- Time (stage), in which soil is classified as mature (zonal) soil, or immature (azonal or young or inceptisol ) soil. Immature soils include regosols, lithosols, silt, alluvium and newly formed organic soils (andosols)
- Suitability to agriculture such that there can be fertile soil and infertile soil.
- Drainage of soil, in which soil is classified as well drained or poorly drained.