Definition of Soil

The soil is a natural medium that acts as a basement for all other materials and living entities. Normally the definition of soil has a variation person to person according to the point of view of their perspective. The definition of soil to a farmer is not similar to the definition of soil to an engineer. However, the soil composition can also be understood from the definition of soil.

Two Definitions of Soil

According to Kellogg (1960),

“Soil is the collection of natural bodies occupying portions of the earth’s surface that support plants and that have properties due to the integrated effect of climate and living matter, acting upon parent material, as conditioned by relief, over periods of time (Hartemink, 2016).”

According to Hilgard (1892),

“Soil is more or less a loose & friable material in which plants, by means of their roots find a foothold for nourishment as well as for other conditions of growth.”

Soil Composition

The soil is a combination of different types of minerals, organic matter, different gases together with the water portion. Because of this, soil can be termed as a heterogeneous body. The percentage of different compounds of soil are given below:

1. Soil Organic Matter

A very small amount of organic substance can be found in soil. The source of organic matter is almost plant and animal (Kheyrodin, 2014). Based on the decomposition stage,  there are three types of organic matter:

a. Undecomposed organic matter

b. Partially decomposed organic matter

c. Completely decomposed organic matter

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