(a) Define soil (b) Outline three characteristics of the following soil types: (i) Sandy soil; (ii) Clay (c) Highlight four ways in which soil is important

Answer Details

(a) Definition of soil

Soil is the thin, loose, uppermost layer of the earth's surface made up of weathered rock particles (mineral matter) mixed with decayed organic matter (humus), water, air and living organisms, in which plants grow.

(b) Characteristics of soil types

(i) Sandy soil

• Made of large, coarse particles with wide air spaces.
• Well drained and well aerated, but dries out quickly and holds little water.
• Light, loose and easy to till, but generally low in humus and nutrients (infertile).

(ii) Clay

• Made of very fine, tiny particles packed closely with little air space.
• Poorly drained and poorly aerated; it holds much water and becomes waterlogged.
• Heavy and sticky when wet, hard and cracked when dry, and difficult to cultivate.

(c) Four ways in which soil is important

• It supports plant growth by supplying nutrients, water and anchorage for roots.
• It is the basis of agriculture (crop farming) and grazing, supporting food production.
• It provides a habitat for soil organisms such as earthworms and bacteria.
• It supplies raw materials (clay for pottery/bricks, laterite for building) and helps store and filter water.