Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
7 Cards in this Set
- Front
- Back
|
What did the europeans find who first explored the midwest? |
1) arid prairie grasslands 2) herds of bison 3) native americans |
|
|
What changed in the ecosystem between the Rocky Mountains and the Mississippi River? |
A 1862 act allowed europeans settlers to move in there, each family coming to own 65 hectares. These settlers established farms, and the bison were almost made extinct. |
|
|
What happened to the soil? |
At first the soil from the newly-ploughed was fertile, nutrients were given by livestock manure. However, fertility was lost under the pressure of the high yield and the soil mistreatment. and in the 1930s... Frequent, severe droughts, high winds, soil exhaustion and lack of ground cover caused the the nutrient deprived soil to dry and be swept away and the great plains became the "Dust Bowl". |
|
|
What were some of the impacts of the dust bowl? |
Many families lost their livelihoods, as well as their homes - they had to migrate elsewhere and start over in California. |
|
|
What as America done to conserve the soils? |
After WW2 the USA has tried: crop rotation and strip cropping - to improve nitrogen content planting tree belts - to provide wind protection for soil terracing and contouring ploughing slopes - to prevent soil being washed away implementation of irrigation from the aquifers - to moisten soil |
|
|
What are some concerns that are problematic even in 2015? |
1) overexploitation of the aquifer 2) GM crops 3) farm industry abandonment |
|
|
What are some other changes apart from soil conservation? |
Reintroduction of buffalo |
