(b) Characteristic features of soil Zones
(i) Northern zone of sandy soil
(1) It is found in the Northern parts of the country
(2) The soil is formed under arid condition
(3) The soil is friable, loose and porous
(4) Soil are dark in colour
(5) Soil are fertile
(6) Soil grains are coarse in texture
(7) Soils are not heavily leached
(8) Soils are sand-loam and easy to cultivate
(9) Soils support crops like groundnut, cotton, maize.
(ii) Interior zone of laterite soils
(a) Found in the interior part of the country
(b) Usually reddish or brownish in colour
(c) They are of medium fertility
(d) It is generally sticky when wet and hard when dry
(e) They are heavily leached .
(f) They are impervious
(g) They contain iron and aluminium compounds. The soil is used for growing of food crops, such as yam, cocoyam, cassava, etc.
(iii) Alluvial Soils
(i) Derived from weathered materials
(ii) Found along river valley and lake shores
(iii) Associated with river deposits
(iv) Rich in humus
(v) Colours vary according to deposits
(vi) Soils are fine grains
(vii) Underlain by clay Support growth of rice, sugarcane, cassava, etc
(iv) Forest Soils
(a) Associated with forest vegetation
(b) Found in Southern part of Nigeria
(c) Rich in humus
(d) Heavily leached
(e) Support growth of economic trees such as: Mahogany, obeche, Iroko.
(f) Some are acidic