(a) Define the term soil. (b) Outline three functions of soil. C. Highlight any two negative effects c' man's activities on soil. (d) Describe any two metho...

Answer Details

(a) Definition of soil

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

(b) Three functions of soil

• It anchors plant roots and holds plants firmly in place.
• It supplies plants with water, air and mineral nutrients.
• It provides a habitat for micro-organisms and small animals that recycle nutrients.
• It serves as a medium for farming and a base for building.

(c) Two negative effects of man's activities on soil

• Soil erosion: deforestation, overgrazing and bad farming expose the soil so that water and wind wash or blow away the fertile topsoil.
• Loss of fertility/degradation: continuous cropping without rest, and burning, exhaust the nutrients and destroy the soil structure.
• Pollution of soil by chemicals, refuse and oil spillage.

(d) Two methods of conserving soil

• Contour ploughing/terracing: ploughing across the slope and building terraces to slow run-off and check erosion.
• Crop rotation and fallowing: alternating crops and resting the land, plus adding manure/fertiliser, to restore fertility.
• Afforestation and cover cropping to bind and shade the soil, and mulching to protect the surface.