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Difficulty: Very hardSoil Types, Distribution, and Soil Conservation in Nigeria

A pedological survey conducted along a south-to-north transect from the Niger Delta through the Middle Belt to the Sokoto-Katsina plains reveals distinct regional soil characteristics, weathering regimes, and environmental vulnerabilities. Which of the following statements correctly synthesizes the spatial relationship between the predominant soil group of a zone, its primary formation process, and the appropriate soil conservation strategy in Nigeria?

  1. Ferrallitic soils in the southern rainforest zone are formed through intense leaching and silica removal under high rainfall, requiring cover cropping and minimal tillage, whereas northern Regosols derived from aeolian drift require shelterbelts to combat wind erosion.Answer
  2. B
    Regosols dominate the humid Niger Delta due to continuous alluvial deposition during river flooding, requiring hillside terracing, whereas Ferrallitic soils characterize the semi-arid Sokoto Plains where contour bunding prevents glacial runoff erosion.
  3. C
    Hydromorphic soils originate on the Jos Plateau from metamorphic slate rock deposition requiring deep subsoil ploughing, while Ferruginous tropical soils are restricted to coastal mangrove swamps where afforestation stops wind deflation.
  4. D
    Ferruginous tropical soils in the Guinea Savanna form primarily by rapid down-slope mass wasting of unweathered parent rock under gravity, requiring strip cropping to halt solifluction, while southern soils undergo zero chemical weathering.

Answer

Ferrallitic soils in the southern rainforest zone are formed through intense leaching and silica removal under high rainfall, requiring cover cropping and minimal tillage, whereas northern Regosols derived from aeolian drift require shelterbelts to combat wind erosion.
The correct answer accurately synthesizes the pedological gradient across Nigeria. High precipitation in the southern rainforest belt causes severe leaching (desilication) forming acidic, iron-rich Ferrallitic soils that need cover crops to prevent water erosion. Conversely, the dry northern fringe contains coarse Regosols derived from wind-blown desert sands where tree shelterbelts are critical to reduce wind erosion.

Step-by-Step Solution

1
Analyze the latitudinal soil distribution of Nigeria from south to north.
Southern humid zones feature Ferrallitic soils (Latosols); central savanna belts feature Ferruginous tropical soils; river valleys feature Hydromorphic soils; far northern dry zones feature Regosols and brown soils on aeolian sand drifts.
Rainfall amount and duration decrease northward, governing weathering intensity and soil organic matter.
2
Identify key soil formation processes and degradation threats per zone.
In the high-rainfall south, intense leaching (ferrallitization/desilication) strips bases and leaves iron/aluminum oxides, making topsoil vulnerable to water erosion. In the far north, wind erosion (deflation) attacks coarse, loosely consolidated Regosols.
Leaching requires heavy precipitation, while wind erosion predominates in arid regions with scanty vegetation cover.
3
Match conservation measures to specific regional degradation mechanisms.
Cover cropping and mulch protect southern soils from heavy raindrop impact and sheet wash; afforestation and shelterbelts act as windbreaks in the semi-arid northern borderlands.
Effective soil conservation must target the primary erosive agent (water in the south, wind in the north).

Key Concept

Zonal Soil Types, Weathering Processes, and Regional Soil Conservation in Nigeria
Estimated Time:2m 0s
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Topics

Soil Types, Distribution, and Soil Conservation in Nigeria

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