Ensuring Food Supply (Cambridge (CIE) IGCSE Biology): Revision Note

Intensive food production

• Making food production more intensive means producing food more efficiently with a finite amount of land and other resources

• Modern technology has increased food supply substantially:

  • Agricultural machinery has replaced humans and improved efficiency due to the ability to farm much larger areas of land

  • Chemical fertilisers improve yields by increasing the availability of soil nutrients, meaning that plants can grow larger and produce more fruit

  • Insecticides and herbicides kill off unwanted insects and weed species, meaning that there is less damage done to plants by insects, and reduced competition from other plant species

  • Selective breeding produces breeds of animal and crop varieties that reliably produce high yields

Intensive livestock farming

• Intensive farming of livestock increases energy efficiency by reducing energy inputs in relation to yield, e.g. by

  • keeping livestock in a small area, so reducing the energy that animals put into movement; this energy can instead be used for growth

  • feeding animals on high energy foods, so more energy is gained per unit of food digested

  • regularly giving medication such as antibiotics as a preventative measure against disease

  • keeping animals in artificially warm environments so that animals expend less energy regulating body temperature

Advantages of intensive livestock farming

• Less land is required to produce large amounts of food

• Food can be produced all year round in controlled environments

• The cost of production is lower, so food can be sold at cheaper prices

Disadvantages of intensive livestock farming

• Ethical issues associated with cruel treatment of animals in intensive farms

• Natural habitats may be destroyed to maximise land available for keeping livestock

• Ecological issues with intensive farming include:

  • reduction in biodiversity in areas where large amounts of land are used to graze cattle (as only grass is grown so in effect it becomes a monoculture)

  • overgrazing can lead to soil erosion

  • large numbers of cattle produce large amounts of methane, a greenhouse gas

  • the waste excreted by livestock can be washed into waterways, causing water pollution

Monocultures

• Monoculture farming means that only one type of crop is grown on an area of farmland

  • E.g. trees for palm oil grown in the Indonesian rainforest

Advantages of monocultures

• Monoculture farming allows for the use of specialised machinery for planting, weeding, and harvesting, leading to increased efficiency and reduced labour costs

• Focusing on a single crop can allow farmers to optimise conditions for that specific crop, resulting in higher yields 

Disadvantages of monocultures

• Monocultures reduce biodiversity

  • Crop monocultures only contain one variety of plant, so provides food for few species of herbivore, which in turn cannot support more than a few predator species

• Another issue with monocultures is the increase in pest populations; if a particular pest feeds on a crop, farming it in large areas repeatedly means there is an ample supply of food for the pest, causing the population to increase

• Often farmers will spray insecticides onto crops to control the pests; this leads to:

  • harmless insects being killed as well

  • pollution by pesticides

  • pesticide resistance; where the same chemicals are used repeatedly for specific pests, the pests may eventually become resistant to them, reducing their effectiveness