Population and the Environment - (Soils)

Question 1

Under what climatic conditions do Podzol soils form?

Answer 1

Cool, humid climates with high rainfall (e.g., boreal forests)

Key diagnostic horizons include the acid, ash-grey E horizon and the dark, cemented spodic Bhs horizon.

Question 2

In which regions are Podzol soils most commonly found?

Answer 2

Northern Europe, Siberia, Canada, upland areas of the UK

Patchy occurrences under coniferous or heath vegetation in other temperate zones.

Question 3

What are the main agricultural limitations of Podzol soils?

Answer 3

Low natural fertility, strong acidity (pH 3.5–5.5), intense leaching, shallow poorly structured E horizon

These factors limit water retention and root penetration.

Question 4

What two major soil-related problems affect Podzols once vegetation is removed?

Answer 4

Acidification and erosion of the thin A horizon

Acidification leads to aluminum toxicity.

Question 5

What management practices can improve Podzol soil productivity?

Answer 5

Liming, NPK fertilizer, organic manures, deep ploughing/subsoiling, afforestation

Afforestation examples include Sitka spruce.

Question 6

Under what climatic conditions do Tropical Red Latosol soils form?

Answer 6

Hot, humid tropical climates (e.g., equatorial rainforests, monsoon areas)

Characteristic color due to deep weathering leaving iron and aluminum oxides.

Question 7

What gives Tropical Red Latosol soils their characteristic red/yellow color?

Answer 7

Dominance of iron and aluminum oxides due to deep weathering

This occurs in hot, humid tropical climates.

Question 8

Where are Tropical Red Latosol soils predominantly distributed?

Answer 8

Amazon Basin, Central Africa, Southeast Asia, parts of northern Australia

These areas include regions like Indonesia.

Question 9

What are the main agricultural limitations of Tropical Red Latosols?

Answer 9

Very low natural fertility, rapid nutrient leaching, phosphorus fixation, high drainage

These factors can exacerbate drought stress in dry seasons.

Question 10

What key soil problems arise from continuous cultivation and vegetation removal on Latosols?

Answer 10

Nutrient depletion, severe erosion, acid sulfate formation

Nutrient depletion is often referred to as ‘mining’ of soil reserves.

Question 11

Which management practices can sustain agriculture on Tropical Red Latosols?

Answer 11

Shifting (slash-and-burn), agroforestry, targeted inorganic fertilization, terracing/contour bunding

These practices help reduce erosion and conserve moisture.