10. Soil degradation
Erosion • Water erosion makes 60% of soil degradation
Overuse • Overgrazing, overcropping, increasing erosion
• Slash and burn techniques leave nutrient poor soils
Deforestation unproductive after several crop cycles, increasing erosion
Acidification • Also called toxification, releases toxic metals
• Minerals in the water concentrate in the soil in dry or coastal
Salinization areas
Desertification • Spreading of desert into once productive areas
• Increasing all the above problems due to change in land use
Climate change and hydrology
15. Soil conservation
Reduce water flow
• Contour ploughing
• Terracing
• Gullies and ravines fenced and planted with trees
Erosion control after harvest
• Keep crop cover as long as possible
• Keep stubble and root structure after harvest
• Plant a grass crop or crop rotation
Long term
• Smaller fields
• Grow a tree crop
• Wind barriers
• Stop use of marginal lands
• Use of lime or organic material to improve soil condition
16. What issues can you see here?
Bad:
• Slope
increased erosion
• Fields very large
• Monoculture –
crop rotation?
Good:
• Tree buffers that
can absorb
surface runoff,
lower wind
erosion
• Harvest does not
allow soil to be
exposed
• Contour
ploughing
17. Soil management
Subsistence farm
• Only enough food for family or small community
• Labor intensive
• Linked with poverty
• Good for the environment
• no GMOs, polyculture, limited selective breeding
18. Soil management
Commercial farm
• High technological input
• Low labour
• High yields
• Bad for the environment
• GMOs, monoculture, selective breeding
19. Another way to describe farming:
Extensive farming – Farms that are large in
comparison to the money and labour put
into them eg. large cattle ranches
Intensive farming – Farms that are small but
have high output (due to capital and labour)
eg. feed lots for cattle
26. Food production
systems
North American Subsistence
cereal farming farming in SE Asia
Inputs: Inputs:
High technology, high fertilizer Low technology, natural fertilizers, high
use, low labor labor
System characteristics:
Genetically modified organisms, System characteristics:
monoculture Polyculture, crop rotation
Environmental:
Clearance of natural ecosystems, loss
of species diversity, soil erosion Environmental:
Sustainable
Outputs:
Low hectare efficiency output as is Outputs:
extensive not intensive, but high Only enough to feed family or small
farmer output community, high efficiency
27. Food production
systems
Intensive beef
Maasai tribal use of
production in
livestock
MEDCs
Inputs: Inputs:
High technology, heating, food Low – no fences, only human input
System characteristics:
System characteristics: Nomadic form of subsistence farming
Selective breeding, intensive farming
Socio-cultural:
Cattle the source of all social roles and
Socio-cultural: status
Ethics of restrained animals
Environmental:
Environmental: Low impact, but social gains of wealth and
Greenhouse gases, waste, transportation quantity can lead to overgrazing and
desertification
Outputs:
Outputs:
High relative to extensive beef farming
Low – subsistence farming, efficiency high
28. Food production
systems
Commercial
Rice-fish farming in
salmon farming in
Thailand
Norway/Scotland
Inputs: Inputs:
High use of antibiotics and steroids Low technology, high labor, fish stock
System characteristics:
Polyspecies
System characteristics:
Monoculture, high selective breeding
Environmental:
More natural ecosystem but relies on
Environmental:
introduced species
Food taken from ecosystem depleting other
species, good in that it leaves wild stocks of Socio-cultural:
salmon alone to breed Competition from poultry, beef, pork, and
marine fish
Outputs: Outputs:
High efficiency and high output per High output per hectare, low output per
hectare and per farmer farmer
33. Case study
Punjub region the bread belt for
India
Relies on groundwater for irrigation
Increasing population and
intensive agriculture
Unsustainable use of water - water
table dropping 1 meter a year
Agricultural output in decline
