In soil geography, soils that have undergone gleying and are typically associated with marshes, swamps, or poorly drained uplands are collectively known by which of the following names?

Introduction / Context:
Soil types are often classified not only by parent material but also by the dominant processes that have affected them. One such process is gleying, which occurs under conditions of prolonged waterlogging. This question asks you to identify the term used for soils that show gleyed features and are commonly found in marshes, swamps, and poorly drained uplands. Recognising this term is important for physical geography and environmental science.

Given Data / Assumptions:

• The soils have undergone gleying, indicating waterlogged, anaerobic conditions.
• They are found in marshes, swamps, or poorly drained upland areas.
• Options include calcimorphous soils, hydromorphic soils, halomorphic soils, and sierozems.
• We assume basic understanding of soil forming processes.

Concept / Approach:
Hydromorphic soils are those whose properties have been strongly influenced by excessive moisture. Prolonged saturation with water leads to reducing conditions, iron becomes mobilised and reprecipitated, and characteristic grey, blue, or mottled colours develop, a process called gleying. Calcimorphous soils are influenced by calcium carbonate, halomorphic soils by soluble salts, and sierozems are desert grey soils. Therefore, the name that matches gleyed, waterlogged soils in marshes and swamps is hydromorphic soils.

Step-by-Step Solution:
Step 1: Connect the word gleying with waterlogging and reducing environments where oxygen is scarce and iron compounds are chemically altered. Step 2: Recognise that marshes, swamps, and poorly drained uplands are all environments where water remains in the soil for long periods. Step 3: The general term for soils whose formation is dominated by water saturation is hydromorphic soils, where hydro refers to water. Step 4: Calcimorphous soils are associated mainly with high calcium carbonate content and calcareous parent materials, not necessarily with waterlogging. Step 5: Halomorphic soils are associated with high salt content, especially in arid and coastal environments, distinct from purely waterlogged conditions. Step 6: Sierozems are typically light coloured desert soils with limited organic matter and not specifically gleyed marsh soils. Step 7: Therefore, the correct term for gleyed soils in wetland environments is hydromorphic soils.

Verification / Alternative check:
Soil science texts state that hydromorphic soils develop under conditions of poor drainage and water saturation, showing gleyed horizons with grey or blue colours and mottling. These features are typical of marshes, swamps, and seasonally waterlogged uplands. By contrast, calcimorphic and halomorphic classifications refer to soils dominated by calcium or salts, and sierozems are tied to arid climates. This confirms that hydromorphic is the correct general label for the soils described.

Why Other Options Are Wrong:

• Calcimorphous soils: Influenced mainly by calcium carbonate accumulation, often in semi arid regions, not specifically gleyed wetland soils.
• Halomorphic soils: Strongly affected by soluble salts, found in saline or sodic environments rather than in marshy, fresh water wetlands.
• Sierozems: Desert grey soils formed under arid conditions, not in waterlogged marsh or swamp settings.

Common Pitfalls:
Because the options all contain somewhat technical names, learners may pick one at random or confuse hydromorphic with halomorphic due to the similarity in sound. To avoid this, focus on the prefixes: hydro indicates water, halo refers to salt, and calci points to calcium. When you see gleying, marshes, or swamps in the question, you should immediately think of waterlogged conditions and match them with hydromorphic soils.

Final Answer:
Soils that have undergone gleying in marshes and swamps are called hydromorphic soils.