Question

Difficulty: Very hardSoil Formation, Profiles, and Major Vegetation Types

Match each pedogenic process involved in soil profile formation on the left with its corresponding chemical characteristic and profile manifestation on the right.

  • PodsolizationIntense leaching of bases and iron/aluminum oxides under acidic conifer litter, leaving an ash-grey silica-rich eluvial E horizon.
  • Lateritization (Ferrallitisation)Deep silica removal by heavy rainfall under warm temperatures, resulting in the accumulation of reddish iron and aluminum sesquioxides.
  • CalcificationPrecipitation of calcium carbonate in lower subsoil horizons due to evapotranspiration exceeding precipitation in semi-arid regions.
  • GleizationAnaerobic reduction of ferric compounds into bluish-grey ferrous iron under prolonged waterlogging and oxygen-depleted conditions.

Answer

Podsolization matches with intense leaching producing an ash-grey silica-rich E horizon. Lateritization matches with silica removal yielding reddish iron and aluminum sesquioxide accumulation. Calcification matches with precipitation of calcium carbonate in subsoil under moisture deficit. Gleization matches with anaerobic reduction of ferric iron into a bluish-grey reduced horizon.
Each pedogenic process corresponds directly to its specific climatic, vegetation, and biochemical mechanism: podsolization forms ash-grey leached upper horizons under cool coniferous litter; lateritization concentrates red sesquioxides via tropical desilication; calcification precipitates calcium carbonates in semi-arid subsoils; and gleization reduces iron under anaerobic waterlogged conditions to give a bluish-grey horizon.

Step-by-Step Solution

1
Analyze Podsolization
Identified as typical of boreal coniferous forests producing acidic chelation and ash-grey eluvial horizons.
Acid mor humus mobilizes sesquioxides downwards, leaving quartz-rich E horizons.
2
Analyze Lateritization
Identified as humid tropical weathering characterized by desilication.
High temperatures and abundant moisture dissolve silica while leaving insoluble iron and aluminum oxides.
3
Analyze Calcification
Identified as arid/semi-arid pedogenesis where evapotranspiration exceeds rainfall.
Restricted leaching causes calcium carbonate accumulation in horizon B.
4
Analyze Gleization
Identified as hydromorphic pedogenesis in saturated soils.
Lack of oxygen drives microbial reduction of iron from ferric to bluish-grey ferrous state.

Key Concept

Pedogenic processes controlling soil profile development across global climatic zones.
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