Human Impact on Ecosystems (Edexcel IGCSE Geography): Revision Note

Impact of farming systems

• To obtain food humans use and modify the ecosystems through farming

• There are four groupings commonly used to categorise farming:

  • Categorisation by outputs

    • Arable (the cultivation of crops) and pastoral (raising livestock)

  • Categorisation by whether a profit is made

    • Commercial (farming to gain profit) and subsistence (farming to feed farmer and family)

  • Categorisation by the inputs

    • Extensive (a farm with low inputs or yields per hectare) and intensive (a farm with high inputs or yields per hectare)

  • Categorisation by location

    • Nomadic (farmers moving seasonally with crops/livestock) and sedentary (where the same area of land is farmed every year)

• A farm that has both livestock and grows crops is a mixed farm

Farming systems

• All farms are systems, they have inputs, processes and output

Impacts of farming systems

• All farming systems impact the ecosystem in which they are located

• Some have more impact than others

• Commercial farming tends to:

  • increase monocultures which reduces diversity because the animals have no access to a wide range of foods

  • mean that nutrient cycling is dependent on fertilisers added to the soil, which may be natural (manure) or artificial fertilisers

  • modify the ecosystem with inputs of seed, fertiliser, pesticides, herbicides and the use of machines

  • reduce the links within food webs

  • reduce the amount of biomass