Classwork Series and Exercises {Agricultural Science – JSS2}: Physical Properties Of Soil

Agricultural Science, JSS 2,Second Term

Topic: Physical Properties of Soil

Physical properties of Soil

These are properties that can be easily evaluated by visual inspection or by feel. They can be easily measured by some kind of scales such as size, shape and strength or intensity.

The physical properties of the soil include;

1. Soil texture
2. Soil structure
3. Soil colour
4. Soil consistency  

Soil texture

This is the degree of fineness or coarseness of the mineral particles of a soil. This can also be defined as the relative proportions of sand, silt and clay in the soil.

Importance/effects of soil texture

• Determines the capacity of the soil to hold water and to circulate air.
• Determines the amount of surface area available for reaction.
• Influences the response of crop to fertilization

Soil structure

This is the arrangement of the soil particles into aggregates of different sizes and shapes. When there is little or no aggregation of particles, the soil is said to be structured, e.g. loose sand.

The types of soil structure include;

• Plate like structure
• Prismatic Structure
• Block like structure
• Spheroidal structure
• Crumb structure
• Single grained structure

Importance/effects of soil structure in agriculture

• Loose, friable soils are easier to cultivate.
• Facilitates the activities of micro-organisms.
• Increase the water holding capacity of the soil.
• Increases the aeration of the soil

Soil Colour

This refers to physical appearance of the soil. Soils are commonly described as

• Light e.g. White, whitish-grey etc.
• Bright e.g. Yellow, Orange, red, reddish-brown, yellow-brown.
• Dark e.g. black, dark grey, dark brown.

Soil Consistency

This refers to the ability of the soil to hold/stick together. The degree of cohesion of a soil, its resistance to deformation when worked on or its resistance to the insertion of an instrument when worked on or its resistance to the insertion of an instrument like a cutlass, shovel, knife or hoe is a measure of its consistence.

Important Effects of Soil Consistency

• It is useful in estimating the support strength under applied force.
• It also enables the farmer to plan the best time for land preparation.