BRAINCAKEFarming: Depletion of Resources
Feeding a growing population requires more food from each hectare and more land for farming. Intensive farming has increased yields enormously, but it can deplete the resources on which future farming depends.
Soil: ploughing, removing hedgerows and leaving soil bare expose it to wind and rain, causing soil erosion. Growing the same crop year after year removes the same mineral ions each time and reduces organic matter, so soil fertility and structure decline. Soil forms extremely slowly, taking hundreds of years to make a few centimetres, so it is effectively non-renewable on a human timescale.
Water: irrigation uses about 70% of the fresh water taken by humans. Pumping groundwater faster than it is replaced lowers water tables, and in dry regions evaporation of irrigation water leaves salts that make soil infertile (salinisation).
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Key terms in this lesson
- desertification
- The process by which fertile land becomes desert, often as a result of overgrazing, deforestation or drought.
More in Human Influence on Ecosystems
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- The Effect on Organisms
- Changes in Species Distribution
- Fishing: Depletion of Resources
- Anthropogenic Changes in the Ocean
- Problems with Conservation
- Fish Farming and Aquaculture
All 29 lessons in Human Influence on Ecosystems · All Edexcel A-level Biology topics