Post on 05-Apr-2017
transcript
Topic 5Soil systems and terrestrial food production
systems and societies
5.2 Terrestrial food production systems and food choices
Norman Borlaug
Food Production• About one sixth of the human population is undernourished
(about 1 billion people)• The majority of these are in LEDCs• Meanwhile there is an increasing obesity problem in MEDCs and
huge wastage of food resources• In LEDCs, food production is generally subsistence, in MEDCs it is
commercial• MEDCs attempt to protect their own farming industries by
imposing import tariffs and export subsidies, and this makes it difficult for LEDCs to switch from subsistence farming
• MEDCs are becoming more dependent on cash-crops• Very often, LEDCs have little to export other than food crops• There is therefore an imbalance in global food supplyhttp://edroness.blogspot.mx/2014/08/subsistence-farming-vs-intensive-farming.html
Food ProductionIntensive agriculture Subsistence agriculture
High yields Low yields
High dependence on technology Little technology
High level of mechanisation Use of manual labour
Cash crops Food grown to feed family
High use of synthetic fertilizers and pesticides (leads to pollution of watercourses)
Dependence on organic fertilisers if available
Use of irrigation (leads to soil salinisation) Access to water may be very limited
High rate of soil and nutrient degradation Lower rate of soil degradation but lack of technology to ameliorate effects
Food Prices• World food prices have been
increasing recently• There is increasing meat
consumption in MEDCs and LEDCs• More staple crops are being used
as animal feed• Also more farmland is being used
to grow biofuels (especially in Brazil) - Land is becoming more expensive and more limited
• World oil prices are unstable and transportation costs are therefore increasing
World Food Price Index
Effects of Climate Change on Agriculture
• Expected to have a greater effect on LEDCs than MEDCs
• Increased occurrence of drought• Increased occurrence of flooding (especially in low-
lying areas like Bangladesh)• Increased occurrence of super-high temperature
events (>40oC) in countries like India, which can destroy entire crops over large areas
• LEDCs will be less economically able to implement measures to avoid agricultural problems
effects of climate change on agriculture
Terrestrial and Aquatic Systems• Terrestrial farming (e.g. arable and herbivore farming)
harvests low trophic levels• In MEDCs we generally want a large variety of foods, and
this also gives a more healthy diet • Use of terrestrial animals gives other benefits like milk,
leather and wool production• Aquatic farming (e.g. fish farming) generally harvests high
trophic levels• The Second Law of Thermodynamics shows that more
energy must be put into an aquatic system to harvest the same amount of biomass
effects of climate change on agriculture
Terrestrial and Aquatic Systems
Terrestrial Food Production
Intensive farming – large input of labour, fertiliser, pesticides etc.Very efficient use of the land area available
Extensive farming – low input of labour, fertiliser etc. in relation to the area of land used
Subsistence farming – non-commercial, labour-intensive, range of crops, low availability of synthetic fertilisers and pesticides etc.
Aquatic Food Production
• This may involve sea fishing (extensive) or aquaculture (intensive)
• One of the biggest aquaculture businesses is commercial salmon fishing e.g. in Scotland
• It takes 2-3 kg of fish to produce 1 kg of salmon (this food is provided by sea-fishing)
• It involves intensive use of antibiotics• Produces large amounts of waste• Escaped farmed fish present a problem to local
ecosystems either through predation or interbreeding
Food Production and Social Systems
• Forest dwellers (Amazon Basin)– Slash and burn (extensive subsistence farming)– Clearance makes land available for agriculture– Ash from burning trees fertilises the soil (short-term)– Once the soil is depleted the farmer moves on– The original land may then regain its fertility– It only works with low population densities– It is linked to ritual and respect for the forest and previous
generations that worked the same land– Labour intensive; lack of machinery prevents people from
over-farming the land– Not all the wood is burned, it is also used for housing, fuel
reserves etc.
Food Production and Social Systems
• Rice cultivation (South East Asia)– Padi fields are typical in S.E. Asia (intensive
subsistence farming)– High population densities, large demand– In wet areas, often close to rivers and often employ
terracing– Require clay-rich, nutrient-rich, low-drainage soils – Warm climates allow many harvests per year and high
productivity– Increasing population density and rising land costs are
making padi cultivation more difficult– Some farmers are looking to increase diversity to
combat this (e.g. livestock, citrus, or cultivating fish in the padi fields)
Terraced padi fields in Bali
Food Production and Social Systems• Crop cultivation in U.K.
– After the second world war, western Europe and the U.S. switched from small low production family-owned farms to large-scale intensive commercial farming
– Small pieces of land were combined and hedgerows destroyed
– Increased use of synthetic fertilisers, pesticides and recently GMOs
– Typified by monoculture and mechanised ploughing and harvesting
– Crop rotation and fallow periods abandoned in favour of intensive use of fertilisers (farmland also became large-scale sites for the ‘disposal’ of sewage sludge)
– This has led to large scale changes in society, consumer dependence on the supermarket, large productivity and large amounts of waste and high expectations of the consumer
Sustainable Agriculture
• Increased sustainability may be achieved through:– altering human activity to reduce meat consumption
and increase consumption of organically grown and locally produced terrestrial food products
– improving the accuracy of food labels to assist consumers in making informed food choices
– monitoring and control of the standards and practices of multinational and national food corporations
– planting of buffer zones around land suitable for food production to absorb nutrient runoff