Edaphic factors deal with the structure formation and characteristics of different types of soils.
Soil provides mechanical anchorage to plants and holds water and mineral ions for the plants. They provide a “basis for the activities of microorganisms and animals. Soil contains organic and inorganic colloids, electrolytes, organic matter and soil organism.
Soil water forms the life line of soil organisms, since proper growth of microorganisms and soil invertebrate population 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 C02, 02, and N2 while their quantity differs from soil to soil. The soil air is a very important edaphic factor that determines the types of microorganisms, soil animals and vegetation that can grow in the soil.
Similar to soil water, it also brings about morphological, physiological and anatomical changes in plants and animals.
Soil temperature is very important as it affects the growth of microorganisms, plants and animals. The soil temperature influences root growth, the ability of the roots to absorb nutrients and movement of organism.
Soil pH and salinity are also important because when the pH of the soil is very high (highly alkaline) there is no vegetation.
Soil organism like bacteria, fungi, 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 increase soil fertility.
Thus, a change in any of the soil constituents will have a tremendous effect on the whole.