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