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14 Cards in this Set
- Front
- Back
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Which biome is the Midwest of USA?
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Temperate grassland biome
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What originally grazed on the prairie grasslands? |
Bison (buffalo), provided food for native Americans |
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What happened in the Midwest of USA in 1862? |
An act was introduced which allowed Europeans to settle in the grasslands. Each family was allowed 65 hectares of land, most used this for farming. |
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Why did fertility in the soil begin to drop? |
Because of the pressure of continuous crop growing. |
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What happened in the 1930s and why?
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A succession of: severe droughts, high winds, soil exhaustion and lack of ground cover caused the soil to be swept away from large areas of land. Great plains became a "dust bowl". |
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What happened to most families after the 1930s?
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They were forces to migrate westwards towards California.
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What has happened since the end of WWII (1945)? |
Methods of soil conservation have been successfully applied |
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How has the nitrogen content of the soils been improved? |
By crop rotation and strip cropping |
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What does planting tree belts do to help soil conservation? |
Provides protection from wind erosion |
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What does retaining straw and crop litter after the harvest do to help soil conservation?
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Protects the soil from wind and rain showers
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What does terracing and contour ploughing sloping areas do to help soil conservation?
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Prevents soil being washed away |
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What does increasing irrigation do?
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Increases the crop yield and productivity in times of drought |
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What are the new concerns about the Midwest of USA |
The growing of GM crops |
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How is some of the land being restored to its original prairie grassland?
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Herds of buffalo are being re-introduced |
