Edaphic factors are defined as ‘ecological influences properties of the soil brought about by its physical and chemical characteristics’.

Soil: can be recognized as surface soil, sub-soil and forest soil. If a section of soil is observed from its surface to the underlying rock, horizons (layers) are seen. A vertical section with respect to the sequence of layers are called soil profile. Eg. A^oo horizon surface litter; A^o horizon-humus layer; A horizon-Uppermost layer of mineral soil; B horizon-layer formed by washing down from A horizon, etc.

Classification of Soil: Soil is classified into two major groups: Soils whose properties are influenced mainly by the parent material are called Endodynamorphic, whereas properties influenced by factors other than parent material is Ectodynamorphic.

Importance

1. The seeds germinate in the soil and the roots go inside the soil not only to anchor but also to provide nutrients & water
2. Soil provides air to the roots
3. It affects rate of growth of trees, yield of trees and natural regeneration
4. Forester can improve the productive capacity of soil, whereas climatic and topographic factors are beyond the control of foresters.
5. Species composition of a forest depends on the properties of soil