The earth is covered with different variety of soils. It is desirable to systemize or classify the soils into broad groups of similar behavior. it is more convenient to study the behavior of groups than that of individual one. Chemical constituents present in the soil are considered in the classification based on composition. It includes the following types:
a) Black soil
b) Lateritic soil
a) Black soil
The clayey soil having colored and formed from the basic igneous rock like. Basalts is a example of black soil. It mainly consists of iron, aluminum , magnesium, calcium oxides and also some organic matter. Its capacity to retain water is high. Also it swells considerably coming in contact with water. It is highly fertile and well known for growing cotton.
b) Lateritic Soil
It is brown colored soil derived from laterite and mainly consists of iron and aluminum hydroxide having a small percentage of manganese hydroxide, titanium oxide, silica, calcium, magnesium etc. it is not much suitable for agricultural works.
it is a sandy soil of light grey color, with very small percentage of iron and organic content. Being deficient in nutritions components, this soil is not good for agricultural works.
d) Peat soil
This is a dark brownish colured soil formed by the decomposed vegetation matter. Thus, it is rich in organic content with very little sand and clay etc. it is highly porous with good water retaining capacity. For agricultural works it is not very fertile. Being soft and weak it readily subsides under loads.