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9 Cards in this Set
- Front
- Back
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What percentage of agricultural land is degredated? |
40% |
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How much agricultural land is there globally? |
-1/3 of global land is agricultural. -Arable land - 13,812,040 km2 e.g., cereals, cotton etc. -Permanent crops - 1,484,087 km2 e.g., orchards, vineyards etc. -Permanent pasture - 33,55,943 km2. |
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What is the American dust bowl? |
-The land affected had been prairie. -Deep rooted grasses protected soil from water and wind. -Cultivation removed natural protection. -A combination of intense ploughing plus a major drought (1931 - 1939) lead to severe soil erosion. -Mass migration of workers, west to California. |
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How can one reduce soil erosion? |
-Contour ploughing reduces rate of run off. -No till/conservation tillages. -Reduce compaction to speed up infiltration. -Buffer strips up to 20m wide around fields along water courses, on slopes. |
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What are the effects of excessive fertiliser use? |
Nutrient run off and eutrophuication of waters. UK agricultural service advice - apply only in growing season, consider soil nutrient status and crop requirements. Don't apply on steep sloping soil, waterlogged, frozen or snow-covered fields. |
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What are the threats to pollinators? |
Decline in bee populations due to mites, pesticides and neonicotinoids. |
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What were the issues with DDT? |
It was effective as it eliminated yellow fever and reduced malaria but has a long half life in soil, affects non-target organism e.g., bio-accumulates. Makes top predators such as birds of prey have thin eggs which break before being mature. |
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What types of integrated pest management are there? |
Integrated - combines biological control with some pesticides plus methods such as no till agriculture. Biological control - use of predator organisms. Genetically modified crops - highly emotive in the UK but may reduce the need for pesticides. |
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How to hold onto water? |
-Only 15% of water in farming systems is from steams. -Most lost through run-off or evaporation or is in the crops. -Run-off tanks, walls, vegetation, etc help preserve water. -Reduce ploughing. -Use mulches. |
