Soil and Land

Soil is defined as natural substances covering the surface of the earth. It is evolutionary derived from rocks and minerals combining with organic matters, water, and air. Soil is divided into levels parallel to the surface of the earth. The evolutionary process takes thousands of years to become a thin level of soil. The newly made soil has specific characteristics of color, composition, quality and usage depending on the parent materials, minerals, geographic and environment.

Land is ground or soil used for a particular purpose.

 

Soil Composition.

The primary composition of soil is minerals(45%), while water(25%) and air(25%) are secondary whereas organic materials (5%)are the least.

Layer of Soil

1. Top Soil. It is the surface down to 6-15 inches deep. It contains plant nutrients, microorganisms, water, and air which are suitable for plant growth.
2. Sub Soil. This is the next lower layer of top sub soil soil where roots cannot reach. parent materials It is thick and sticky in texture, rocks thereby, less suitable for plant growth.Lower Soil which lies deeper continue from top soil. Some root plant cannot reach. It may be harder than top soil. In general it is less appropriate for plant.

Between these two layers of soil there is a level of soil where erosion of minerals and nutrients are accumulated and could not disperse further to the sub soil layer.