past paper questions

Question 1

Assess the relative influence of factors leading to the salinisation of soils in hot arid and semi-arid environments.

Answer 1

• The main saline soils are solonetz and solonchaks. Solonetz are sodium rich soils with a conspicuous natric (sodic) layer. Solonchaks are pale grey soils with a high concentration of soluble minerals with a fluffy surface layer. Candidates may discuss the following factors involved in salinisation.

Natural factors include:
* lack of rainfall and high temperatures resulting in potential evaporation exceeding rainfall amounts
* this brings soluble salts up into the soil from the water table
* the poor structure of the soils, lacking in humus, is also an important factor
Human factors include:
* over irrigation which brings the water table near the surface
* irrigating with water rich in salts; this includes from inland lakes and from coastal areas

The focus of the assessment should be on the relative influence of these factors. Soil salinisation is a natural process which can be increased by
human activity.

Question 2

With the aid of a case study from either a hot arid or semi-arid environment, assess the effectiveness of solutions to the problems of sustainable management.

Answer 2

There needs to be a detailed case study. Assessment will consider the nature of the problems and possible solutions to the problems. There needs to be a convincing discussion as to what is sustainable and what might be sustainable.

Question 3

With the aid of a labelled diagram, describe the main physical features of the landscape

Answer 3

Candidates may describe:
* Steep-sided valley/wadi/canyon
* Isolated pinnacles
* Sides show vertical and horizontal weaknesses
* Scree/debris slopes at base
* Scree is mixed sizes
* Relatively flat plateau area either side of the canyon
* Mostly bare, but some vegetation in the foreground

Question 4

Suggest how water processes have influenced the formation of the landscape

Answer 4

Processes include:
* Erosion, transportation, deposition by water
* Water-based weathering – mechanical and chemical
* Water-based mass movements

Question 5

Assess the relative importance of the factors influencing
desertification in semi-arid environments

Answer 5

• Human factors – overgrazing, over cultivation including cash crops for export, deforestation, population growth, government policy, overuse of water resources
• Physical factors – aridity, thunderstorms, variability of rainfall, drought, wind action, climate change
• The influence of the human factors is largely to increase the severity of the impacts of the natural factors

Question 6

‘Pressure systems are the most important cause of aridity.’ To what extent do you agree with this statement?

Answer 6

The question is about aridity and not just deserts. Causes might include:
* Pressure systems
* Winds
* Continentality
* Cold ocean currents
* Rain shadow effect
* Variability of rainfall
* Human action – changes in albedo, etc.