Case Study - Prariers

Question 1

Where do the prairies stretch from (2)

Answer 1

• From Canadian Alberta in north to Texas in south
• distance of 4000km

Question 2

Different climates in different areas (2)

Answer 2

• drier west and wetter east
• allowing for wide range of grass species to grow

Question 3

How does summer affect prairies (3)

Answer 3

• Temps of over 30 degrees in July
• Soil moisture deficit
• can result in drought

Question 4

Grass in different areas (3)

Answer 4

• East is wetter
• Tall grass up to 2m
• West is drier
• Short grass up to 0.5m

Question 5

How does chernozem soil get made (3)

Answer 5

• Short lived plants
• Meaning a lot of organic debris
• Resulting in fertile soil

Question 6

Why is chernozem soil useful (2)

Answer 6

• Large amounts of humus
• Good for growing crops and raising livestock

Question 7

Impact of humans on the prairies (3)

Answer 7

• 6 million settlers began to exploit fertile soils of grasslands
• by ploughing them & growing wheat
• 19th century

Question 8

After the dust bowl, what are 5 soil conservation methods in place (5)

Answer 8

• Improving nitrogen content of soils by crop rotation & strip cropping.
• Planting tree belts to provide protection from wind erosion.
• Retaining straw after harvest protects soil from both wind & rain
• Terracing sloping areas to prevent soil being washed away.
• Use of irrigation by pumping water from underlying aquifers

Question 9

4 ways prairies are still under threat (4)

Answer 9

• Soil Erosion : overgrazing by cattle ranching, especially in Western areas.
• Loss of Biodiversity : 214 species threatened
• Aquifer Levels Decreasing : World’s largest aquifer, Oglala under Prairies lost 30m of water.

Climate Change : increased drought as temperatures rise, decreasing crop yields.

Question 10

How many species threatened (1)

Answer 10

236