Problem 19

Background and context

Soil constitutes the outermost loose layer that is present on the surface of Earth. Plants are dependent on soil for the supply of essential minerals. The quality of a soil is determined by its chemical composition, surface features of land, climate of the place, time, and the amount of organic matter present in it. 

A typical soil has four important constituents: air and water, inorganic matter, organic matter, and living matter. The cultivation practices followed on a land and the history of soil also affect the fertility of soil.