population & the environment

• Global food production has changed over time
• Global food production has increased significantly in the last 50 years (three times more food is produced today than in 1970)
• Reasons for increase in global food production

  • More land being put aside to grow crops
  • Technological advancements increasing crop yields
• Global food production is unevenly distributed over space
• Factors influencing how much food can be grown in some areas

  • Physical factors (climate, soils, relief and water availability)
  • Human factors (economic resources and investment in technology)
• Global food consumption has also increased significantly in recent years and there are similar spatial variations across in the globe
• Consumption by lower income countries

  Has increased as they have developed, but total consumption by these countries is lower and increasing more slowly than in developed countries
• More highly developed countries

  Can afford to invest in food production technology to increase yields and can also afford to import more food if it can't be grown locally
• Agricultural Systems

  • Agriculture is an example of an open system  
  • Contains inputs, outputs and processes that turn inputs into outputs
  • Also contain feedback loops
• Subsistence

  • Food is produced to feed family or community and only excess sold or traded
  • Often also extensive
  • Examples - Nomadic pastoralism, West Africa

  Output level - Low
• Commercial - Crops grown or livestock raised to sell for profit

  Often also intensive

  Examples - Large agribusiness growing grain in North America,

  Cattle ranching in South America

  Output Level - High
• Intensive

  High yields per area of land as a result of large investment in capital or labour

  Examples - Horticulture in Netherlands (capital intensive),

  Rice cultivation in India (labour intensive)

  Output Level - High
• Extensive 

  Small inputs of capital or labour per area, leading to low yields

  Examples - Sheep farming in Yorkshire Dales, UK

  Output Level - Low
• Agricultural productivity


  Influenced by physical factors such as climate and soils
• Factors of climate that affect how crops grow

  • Precipitation
  • Temperature
  • Wind
• Precipitation levels and distribution

  Determine water availability for plants and livestock

  Extreme rainfall can damage crops and arid areas need to import water for crops to survive
• Mean annual temperatures

  Between 6°C and 25°C allow for highest productivity and longest growing seasons

  Higher temperatures require more water supply to replace that which is lost to evapotranspiration
• High winds


  Can restrict the growth of plants, particularly in grain crops, but in some locations local wind patterns can be beneficial
• Soil quality


  A key factor in agricultural productivity

  Level of nutrients in the soil varies across the world and different crop varieties require different soil characteristics to thriv
• Other important soil characteristics

  • Depth
  • Structure
  • Mineral content
  • Moisture retention
  • Aeration
• Soil degradation and soil erosion can decrease productivity
• Tropical Rainforest Location -

  • mainly located between the tropics
  • central and south America, western India, south east Asia and Australia
• Tropical Rainforest Climate:

  • hot, wet
  • no seasons
  • temperature constant all year round (27-29C)
  • high rainfall almost 300mm
• Tropical Rainforest Soil & Vegetation:

  • soils are mainly thin, poor and have low nutrient levels due to leeching
  • tall, broad evergreen trees are the dominant plants
  • 4 layers of vegetation
• Tropical Rainforests Future Concerns:

  • fires e.g. Amazon Rainforest 2019
  • 10 - 20% reduction in rainfall - if lose the ability to generate own rainfall and therefore preventing the rainforest ecosystem from existing at all.
  • deforestation - home to nearly 30 million species of plant and animals
• Mediterranean Location:

  • warm coastal regions between 30 and 45C in latitude
  • e.g. Italy, Spain, Greece
  • name comes from the Mediterranean sea
  • can also be found along the coasts of Africa & Australia
• Mediterranean Climate:

  • summer and winter seasons
  • summers are about 35C and very dry (warm - hot)
  • winters are mild - cool (12C) and wet with occasional snow falling at high altitudes
• Mediterranean Soil & Vegetation:

  • shrubs, thorny bushes and small trees with small leaves
  • small & drought resistant
  • fruit trees, grapevines, olives and citrus fruits grow well
  • soils tend to be shallow & well-drained
  • 25% productive
• Mediterranean Population:

  • over 100 inhabitans per km
  • population is very unevenly distributed, more concentrated at the coasts
  • development levels vary from HICs such as Spain and Italy to Morroco
• Mediterranean Agriculture:

  • pastoral farming is not as common because the grass has shallow roots and does not grow well here so grazing land is scarce
  • farming is reliable and food security is high
  • intensive agriculture (grape vines for wine making) which supports wine, sherry and port industries
• Mediterranean Future Concerns:

  • shifting climate belts mean that an increase in just 2C could lead to arid or semi -arid climate belts encroaching on Mediterranean areas resulting in an increasingly dry climate
  • Mediterranean sea is warming at a faster rate than other bodies of water which is affecting marine life such as sea grass and dolphins
  • rainfall levels have been decreasing in winter months which means groundwater aquifers are not being charged
  • more prone to wildfires ( affects farming)
• Podsols Location:

  • found in areas with high precipitation levels & cool temperatures
  • temperate zones
  • e.g. Scotland
• Podsols Characteristics:

  • mix of dark and ash grey horizons
  • acidic
  • low in nutrients
  • slow growth and decomposition
  • most are free draining
• Podsols Human Uses:

  • very acidic which makes them unsuitable for arable farming
  • location is incompatible with growing crops (cold & wet)
  • used for forestry, recreation or extensive grazing
  • limited use range
• Podsols Problems:

  • poor drainage and poor root penetration
• Ferralsols Location:

  • found in tropical regions
  • e.g. Brazil
  • rainfall is high
  • high temperatures
• Ferralsols Characteristics:

  • red or yellow in colour (clays)
  • low pH level (acidic)
  • material is quickly broken down in high temperatures
  • rainfall is high so nutrients that are not quickly absorbed by roots are leached out of the soil
  • well-drained, less susceptible to soil erosion
  • crops growing on this soil are prone to drought
• Ferralsols Human Uses:

  • rubber plantations in brazil
  • shifting cultivation & grazing
  • permanent cultivation requires fertiliser and higher pH
• Ferralsols Problems:

  • limited capacity to store water
  • susceptible to leaching because of high rainfall
• Soil Erosion:

  • repeated erosion reduces the fertility of the soil and removal of topsoil
  • reduction of soil available for rooting
  • loss of seeds, pesticides and fertilisers
  • reducing infiltration and therefore increasing surface run-off

  Damage to the environment:

  • deposition of sediment onto roads
  • damage to quality of water sources
  • sediment in rivers damages spawning grounds