1. Resource & Development
Soil is a living system which takes millions of years to form.
Formation of soil : Soil is the thin upper surface layer on the earth, comprising mineral particles formed by the breaking down of rocks, weathered mineral particles, decaying organic matter, living organism, water and air.
Importance of Soil :
1. Soil is the medium in which plants grow. All living things depends directly or indirectly on soil for food.
2. Agricultural production is basically dependent on the fertility of the soil.
3. The rich deep fertile soils supports high density of population through agricultural prosperity.
Important factors of soil formation
1. Parent Material : The source of the rock fragments that make up the soil is parent material which may either be bedrock or loose sediments transported elsewhere by water wind or ice.
2. Relief : The most important being the slope of land Steep slope encourages the swift flow of the water, so steep slopes usually have a thin soil layer.
3. Climate : Temperature and moisture (rainfall) are the climatic variables of greatest significance in soil formation.
4. Natural Vegetation : Vegetation of various kinds growing in soil performs certain vital function.
(A) The decayed leaf material adds much needed humus to soil there by increasing its fertility.
(B) Roots hold the soil together and so prevent erosion.