Edaphic factors deal with the structure and characteristics of different types of soils. Soil is where the plants normally deve op roots. It holds water and mineral ions for the plants. It provides a basis for the activities of varieties of microorganisms. Soil, contains organic and inorganic colloids, electrolytes, organic matter and soii organisms.
Soil water forms the lifeline of soil organisms; good growth of microorganisms occurs in soil containing adequate moisture. Water is a solvent for the organic nutrients as well as minerals and thus, its contents regulate the physiological, morphological and anatomical features of plants.
Soil air, found in soil pores contains CO,, 02, and X2 and their quantity differ from soil to soil. The soil air is a very important edaphic factor that determines the types of microorganisms, soil animals and vegetation that grows in the soil. Similar to soil water it also brings about morphological, physiological and anatomical changes in plants and animals.
Soil organisms like bacteria, fungi and algae and animals like protozoa, nematodes, earthworms, modify the soil structure, increase soil fertility, and help to form humus. Nitrogen fixing bacteria and blue green algae fix atmospheric nitrogen and increases soil fertility.
The soil- air interface has numerous communities within communities of different kinds of micro-and macro- organisms. Fallen logs, temporary pools, animal nests and the excreta or stools of animals are all examples of complex microcommunities that greatly affect the type of vegetation especially on forest floor.
It should be remembered that soil formation itself is a process of ecologic maturation, although it take place at a very slow rate. Forest and grassland soils involve many centuries of organic accumulation, and they represent the stored capital of very long-term ecologic process.
The soil besides being a food bank is also and aquifer. It is composed of strata or layers, known as horizons, each with definable properties. The nature of soil profile has a major influence on plant community living within it and vice versa.