21.1) Food supply

21.1) Food supply


Modern technology has resulted in increased food production:

  • Agricultural machinery is used to clear the land, prepare the soil and plant, maintain and harvest crops to improve efficiency.
  • Chemical fertilisers are used to provide minerals to increase the yield of crops.
  • Pesticide is a chemical that destroys agricultural pests or competitors:
  • Herbicides are chemicals that kills plants that compete with the crop plant for root space, soil minerals and sunlight.
  • Insecticides are chemicals that destroy the insects that eat the damage the plants.
  • Selective breeding to improve production by crop plants and livestock, eg. cattle, fish and poultry.


The negative impact of monocultures:

  • The whole point of crop farming is to remove a mixed population of trees, shrubs, wildflowers and grasses and replace it with a dense population of only one species such as wheat or beans.
  • Monoculture: when a crop of a single species is grown on the same land, year after year.
  • In a monoculture, every attempt is made to destroy organisms that feed on, compete with or infect the crop plant.
  • So, the balanced life of a natural plant and animal community is displaced from farmland and left to survive only in small areas of woodland, health or hedgerow.


The negative impact of livestock production:

  • Intensive livestock production is also known as ‘factory farming’.
  • Chickens and calves are often reared in large sheds instead of in open fields.
  • Their urine and faeces are washed out of the sheds with water forming ‘slurry’.
  • If this slurry gets into streams and rivers it supplies an excess of nitrates and phosphates for the microscopic algae.
  • This starts a chain of events, which can lead to eutrophication of the water system.
  • Overgrazing can result if too many animals are kept in a pasture.
  • They eat the grass down almost to the roots, and their hooves trample the surface soil into a hard layer.
  • As a result, the rainwater will not penetrate the soil so it runs off the surface, carrying the soil with it.
  • The soil becomes eroded.


The problems of world food supplies:

  • There is not always enough food available in a country to feed the people living there.
  • A severe food shortage can lead to famine.
  • Food may have to be brought in (imported).
  • The redistribution of food from first world countries to a poorer one can have a detrimental effect on that country’s local economy by reducing the value of food grown by local farmers.
  • Some food grown by countries with large debts may be exported as cash crops, even though the local people desperately need the food.


Problems which contribute to famine:

  • Climate change and natural disasters such as flooding or drought; waterlogged soil can become infertile due to the activities of denitrifying bacteria, which break down nitrates.
  • Shortage of water through its use for other purposes, the diversion of rivers, building dams to provide hydroelectricity.
  • Eating next year’s seeds through desperation for food.
  • Poor soil, lack or inorganic ions of fertiliser.
  • Desertification due to soil erosion as a result of deforestation.
  • Lack of money to buy seeds, fertilizers, pesticides or machinery.
  • War, which can make it too dangerous to farm, or which removes labour.
  • Urbanisation (building on farmland); the development of towns and cities makes less and less land available for farmland.
  • An increasing population.
  • Pest damage or disease.
  • Poor education of farmers and outmoded farming practices.
  • The destruction of forests, so there is nothing to hunt and no food to collect.
  • Use of farmland to grow cash crops, or plants for biofuel.
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