PROPERTIES OF NIGERIA SOILS

PROPERTIES OF NIGERIA SOILS

  

 LOCATION

Nigeria is a country in West Africa. The country takes its name from its most prominent river, the Niger. It has a land area of about 923,769Km² The geographic coordinate of Nigeria on the World map is Latitude 4⁰ and 14⁰ N and Longitude 2⁰ E. Nigeria as a country has a vast savannah vegetation and is located in the tropical zone.

It is bounded in the North by Niger Republic and Chad; in the west by Benin Republic, in the East by Cameroon Republic and to the South by the Atlantic ocean.

INTRODUCTION

Soil is defined as the top layer of the earth's crust. It is formed by mineral particles, organic matter, water, air and living organisms.

It can also be defined as the mixture of minerals, organic matter, gases, liquids and the countless organisms that together support life on earth.

Functions of soil

1.     A habitat for organisms.

2.     A medium for plant growth.

3.     A means of water storage, supply and purification.

4.     Acts as an engineering medium.

Soil is the end product of the influence of the climate, relief, organisms and parent materials interacting over time.

Soils are characterized and classified based on its unique inherent properties in the natural horizons of its pedon (a generic name for basic soil entities. It is the smallest volume that can be called a soil).

CLASSIFICATION OF NIGERIA SOILS

                                               i.          Northern zone of sandy soils

                                             ii.          Interior zone of laterite soils

                                          iii.          Southern belt of forest soils

                                          iv.          zone of alluvial soils

The interior zone of laterite soils is made up of sands and clays. The soil in this zone is:

a.     deeply corroded

b.     generally sticky

c.      has low fertility

d.     impervious to water

The soils in this zone is most suitable for road paving and wall construction than for farming.

Zone of alluvial soils: These soils are found on deltas, along the coastal flats or on the flooded plains of rivers. The soils found in this zone do not depend highly on climate and vegetation for their formation. This zone extends from the coastal inland and runs along the valleys of the Niger and the Benue rivers.

GROUPS OF NIGERIAN SOILS

Ø Soils with a high base saturation under savanna vegetation (grassland) - Alfisols, Inceptisols, Vertisols, Cambisols. They are formed from metamorphic, igneous rocks, volcanic and sedimentary parent material.

The soils in the savanna grassland are generally low in organic matter, total nitrogen and available phosphorus.

Ø Soils with a high base saturation under forest vegetation (semi-arid tropics) - Alfisols, Inceptisols, Gleysols and Cambisols. Has high organic matter and high rainfall.

Ø Soils in the semi-arid zone - Inceptisols, Entisols and Andosols. Soils in this zone are derived from Aeolians and are often young soils (Entisols). Have a high base status.

SOIL TYPES

·   Fluvisols

·   Regosols

·   Gleysols

·   Acrisols

·   Ferrasols

·   Alisols

·   Lixisols

·   Cambisols

·   Luvisols

·   Nitosols

·   Arenosols

·   Vertisols

PROPERTIES  OF  SOIL  TYPES

Properties of Fluvisols

- Alluvial and floodplain soils with little profile development.

- The soils have a clear evidence of stratification.

- By and large fluvisols are fertile depending on the deposited   materials.

- Wet in all or parts of the profile due to stagnating ground water and/or flood water from rivers or tides.

- Neutral pH, good to high base saturation.

Properties of regosol

- accumulates organic matter in the top soil.

- has a high or a low base status.

- the parent material is an unconsolidated finely grained weathering material.

- used for extensive grazing.

- has coarse texture.

- occur mainly in poor and desert regions.

Properties of Gleysols

- They are water saturated.

- They are formed under waterlogged conditions produced by rising ground water.

- They are not salty.

Properties of Acrisols

- They are acidic soils with a layer of clay accumulation.

- Their natural vegetation is woodland.

- Low nutrient availability.

- Characterized by their argic B- horizon, dominance of stable low activity clays and low base saturation.

- Low structural stability.

Properties of ferrasols

- Red and Yellow weathered soils with colours which result from an     accumulation of metal oxides, particularly iron and aluminium.

- they have low fertility.

- rich in sesquioxide clays.

- low cation exchange capacities.

Properties of Alisols

- Has high Cation Exchange Capacity.

 - The presence of a dense subsurface layer of accumulated clay of mixed mineralogy containing a significant amount of readily soluble aluminium ions.

- Highly acidic.

Properties of Lixisols

- Strongly weathered soils in which clay has washed out down to an argic B horizon which has a moderate to high base saturation.

- Low aggregate stability.

- Develop on old landscapes in a tropical climate with a pronounced dry season.

- Have low cation exchange capacity.

- Low nutrient availability.

Properties of Cambisols

- High content of weatherable minerals.

- Not dark in colour.

- Absence of a layer of accumulated clay, humus, soluble salts or iron and aluminium oxides.

- They differ from unweathered parent material in their aggregate structure, colour, clay content, carbonate content.

Properties of Luvisols

- Characterized by a surface accumulation of humus overlying an extensively leached lager that is nearly devoid of clay and iron-bearing minerals.

- Have strong accumulation of clay in the B- horizon.

- Not dark in colour.

- Presence of a leafy, humus surface horizon that is seperated from the mineral horizon.

Properties of Nitosols

- Have a thick layer of clay accumulation.

- They are acid soils.

- Strongly weathered kaolinitic soils having an argillic B horizon.

- Deep, permeable structure.

- High nutrient content.

- Have moderate resilience and moderate to low sensitivity. 

Properties of Arenosols

- Low in humus.

- They have excess permeability.

- They have little profile development.

- Occur from arid to humid, from extremely cold to extremely hot regions.

- Have weak capillary transport due to prevailing coarse sand texture.

- Consist of sandy soils developed in a) residual sands, in situ after weathering of old, usually quartz  rich soil material or rock. b) aeolian sands that is recently deposited sands as occur in deserts and beach land.

Properties of Vertisols

- Soils with high content of swelling clays.

- Deep, wide cracks develop during dry periods.

- The vegetation is dominantly tall grasses and scattered trees and shrubs.

- It is always clear where A-horizon ends and B-horizon begins.

- A more brownish or reddish colour in vertisols is attributed to the    presence of Fe-oxides or oxyhydroxides.

- The majority of vertisols is neutral or alkaline (pH) because they are mostly derived from base-rich parent materials. 

 

 CONCLUSION

The mixed mineralogy, high nutrient content, and good drainage of these soils make them suitable for a wide range of agriculture, from grains to orchards to vineyards.

REFERENCE

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Available at www.britannica.com/science/Arenosol. (accessed on

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Joe Tabor. (2001). FAO/UNESCO system of soil classification.

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