Basics of Soil Science

Written by Ahmad Mahmood and Ali Hamed Department of Agronomy, University of Agriculture, Faisalabad

What is Soil?

A dynamic natural body composed of mineral and organic solids, gases, liquids and living organisms which can serve as a medium for plant growth.

Composition of Soil

Soil is composed of 25 % air, 25 % water, ≈ 49 % minerals and ≈ 1 % organic matter

Importance of Soil
Soil provides us food, fiber and shelter
It is a medium for plant growth

What is Soil Science?

It is a scientific discipline that deals with the study of soil as a natural resource for plant growth.

Branches of Soil Science
Soil Genesis: It is the branch of Soil Science that deals with weathering of rocks and minerals and factors and processes of soil formation.
Soil Classification: It is the branch of Soil Science that deals with the systematic arrangement of soils into groups or categories on the basis of their characteristics.
Soil Survey: It is the branch of Soil Science that deals with the systematic examination of soil in the field and laboratory, their description, classification, mapping, and interpretation according to their suitability for different management systems.
Soil Physics: It is the branch of Soil Science that deals with the mechanical behavior of soil mass, the physical properties of soil, with emphasis on the state and transport of matter (especially water) and energy in the soil.
Soil Chemistry: It is the branch of Soil Science that deals with the chemical constitution, chemical properties, and chemical processes taking place in the soil.
Soil Biology: It is the branch of Soil Science that deals with soil inhabiting organisms, their function and activities.
Soil Fertility: It is the branch of Soil Science that deals with the ability of a soil to supply the essential plant nutrients for plant growth.
Soil Salinity: It is the branch of Soil Science that deals with the excess soluble salts present in the soil, their reclamation, and soil management for saline agriculture.
Soil mineralogy: It is the branch of Soil Science that deals with the primary soil minerals and their contribution to the chemistry, physics, fertility, and biology of soils and their relationship to soil genesis.
Soil Conservation: It is the branch of Soil Science that deals with the protection of soil from physical loss by erosion (by wind and water) or chemical deterioration.

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