(a) Definition of soil. Soil is defined as the topmost layer of the earth's crust on which plants grow.
(b) Functions of soil.
(1) It acts as a medium in which plant seeds, spores, etc. grow.
(2) It provides support for growing plants.
(3) It provide water and air for plant roots for enhancement of growth.
(4) Provides habitat for organisms.
(5) It provides nutrients / minerals for plant growth.
(6) Source of raw materials such as clay and sand.
(7) Aid agriculture to provide food for man an animals.
(8) Man builds on the surface of the soil.
(c) Negative effects of man's activities on soil
(i) Exhaustion of soil nutrients through overgrazing and overcropping.
(ii) Accelerated soil erosion due to deforestation and removal of vegetation cover.
(iii) Loss of ground water through capillary forces.
(iv) Soil pollution due to oil spillage and chemical fertilizers.
(v) Mining activities destroy top soil.
(d) Methods of soil conservation
(1) Afforestation.
(2) Bush fallowing.
(3) Strip cropping.
(4) Planting of shelter belts.
(5) Controlled grazing.
(6) Planting of cover crops.
(7) Shifting cultivation.
8) Gully reclamation.
(9) Terracing of slope.
(10). Practice of contour ploughing
(11) Providing good drainage to ensure that the soil is aerated and not waterlogged.
(12) Adopting good agricultural practices e.g. crop rotation.
(13) Treating soil with lime, fertilizer, organic manure, etc.