Download Sustainable Food Production

Key Term: Sustainability
"forms of progress that meet the needs of the present
without compromising the ability of future generations to
meet their needs.“- World Commission on Environment
and Development, 1987
Environmental Impact of primary
food production
 Australia is the driest continent in the world!
 We have an annual rainfall of less than 500mm.
 In general, the areas with highest rainfall are
associated with higher elevations. In the Otways and
south Gippsland, high rainfall can occur at modest
elevations because both these areas are frequently
exposed to moist air streams.
 Agricultural practices that have been used over the last
200 years have negatively impacted on our economy.
 There is a increase in salinity, acidification and soil
erosion as a result of farming practices such as land
clearing, irrigation and the misuse of chemicals.
• Salinity is the saltiness or dissolved salt content of a
body of water. It occurs if groundwater (land fed by
water ) rises, generally when excess water is added to
groundwater supplies- this is called irrigation. As
water reaches the surface, water-logging ( soil is so wet
where there is insufficient oxygen in the pore supply
for plants to respire ) occurs and water and salt emerge
through the topsoil, forming salt crusts and kills
vegetation and crops.
Managing the use of water
 Farmers have to irrigate in order to supply sufficient water for
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orchards, vineyards, vegetable and rice production and pasture for
dairy cows and sheep.
Australia has the highest water storage system in the world, where
70% is used for irrigation.
To support the irrigation systems, the natural landscape is changed
, dams and channels are built and paddocks are levelled to move
water from natural waterways to agricultural production areas.
Pollution and salinty problems threaten hundreds of millions of
dollars in agricultural production
The high levels of irrigation required to grow rice and cotton crops
has led to rising watertables, salinty, the washing of herbicides and
pesticides into the water courses downstream, and the potential for
nitrates to leach into groundwater and cause contamination.
Salinity
 Salinity means there is too much salt in the soil and
most plants associated with food production will not
grow in salty soil.
 Two main causes of salinity: dry-land salinity and
irrigated- land salinity.
 Preventing the creation of saline land will have a major
influence on the long-term sustainability of foodproducing land in Australia.
 http://vimeo.com/13753468
Strategies for sustainable water
use
 Monitoring water quality regularly
 Using new technologies, to flood paddocks quickly
 Using only just enough water for maximum growth and good
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health of the crop or pasture
Maintaining and repairing breaks in channels and banks to avoid
water loss
Enclosing open-channel irrigation systems or using pipe lines to
prevent evaporation
Using irrigation layouts which reduce water use on a farm
Installing sensors to detect when sufficient water has been
applied to the soil
Catching irrigation water in channels and dams and reusing it
Using your own words make a
mind map explaining the
concept of a sustainable food
supply.
Use of chemicals in primary
production
Chemical or inorganic fertilisers: nitrogen based, are
used in agriculture to improve crop yields. To
maintain farming soils nutrient content is to use
artificial fertilisers.
 Herbicides: sprayed on weeds as weeds compete with
food crops such as wheat, oats, rice and barley for
nutrients in the soil. Biodegradable.
 Pesticides: control pests on crops. They have varying
toxicity levels and must be used responsibly.
Problems using
chemicals?
Half of the nitrate in these products is dissolved by
rain. The nitrate runs off the fields and can
contaminate rivers and groundwater, polluting fresh
water systems.
2. Nitrogen is released into the atmosphere and
pollutes the air as well as contributing to acid rain.
3. Chemical residue may remain in the food crop and
accumulate in the body once the food is eaten
1.
Managing the use of chemicals
 Aerial spray contractors flying low to the ground to
spray the crop accurately and prevent spray drifting
onto other paddocks.
 Ensuring this process is carried out on days where
there is little wind to prevent wind drift.
 Using a GPS system for aerial contractors so they can
follow the correct path and apply the correct amount
of chemicals.
 Monitoring crops on a weekly basis
Understanding the text Q 1-10
 1. Identify how irrigation systems can have a negative impact on the natural
environment if they are not managed effectively.
 2. Explain how irrigation systems can be used responsibly and provide
examples of some strategies.
 3. What is ‘salinity’ and why is it a problem for primary producers?
 4. Draw a flow chart to show how irrigated-land salinity occurs.
 5. explain the four strategies that farmers who rely on irrigation could use to
ensure a sustainable water supply.
 6. What are three benefits to rice farmers of the development of
electromagnetic induction surveys.
 7. Explain why the use of chemicals is important in primary production of
food.
 8. What is the difference between herbicides and pesticides?
 9. Outline some of the quality control practices to ensure the food is safe
 10. Describe three ways in which sprays used in food production can be applied
so they have a minimal impact on the environment.
Land Degradation
Land degradation can be caused
through erosion and poor soil
health – both nutrient loss and soil
acidification
Erosion
 Occurs when vegetation covering the land and the surface
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of the land’s crust is damaged, often creating large gullies
Main causes: drought, poor land management
The topsoil provides nutrients needed for plant growth and
when landscape is cleared to grow food crops or plant
pasture, the wind and water can remove the top soil.
Pollution of waterways: the sediment from the topsoil
can be blown and carried into wetlands and streams. This
is a problem as it can carry nitrogen and phosphorus that
pollutes waterways.
Erosion is difficult to overcome as it takes many years to
develop and many more decades to redress.
 Landcare: This unique partnership between
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communities, government and organisations are
achieving great things such as:
Improving farmlands
Conserve, rehabilitate and better manage our
river systems
Improving local coastal and marine environments
Planting millions of native trees, shrubs and
grasses that will produce better soils, water and
air quality
Restoring wildlife habitats
Strategies to minimise soil erosion
 Minimise the amount of tillage
 Leaving stubble to cover the soil after harvest
 Planting trees so their roots will hold the soil in place
 Contour farming: ploughing across a slope following
its elevation contour lines. The rows formed slows
water run-off during rainstorms to prevent soil erosion
and allows the water time to settle into the soil.
 Silt traps: slows the flow of water and catches
waterborne soil and seeds. The seeds caught germinate
and help to slow water movement, resulting in stable
soils.
 Planting windbreaks or shelter belts to reduce soil
erosion, stabilise hillsides and waterways
Poor soil health
 Soil acidification: plants take up nutrients and
release acidic waste from their roots. Once soil
becomes acidic, crops and pasture do not grow very
well and the productivity of the land decreases
 Using the same soil for crops to grow in, has caused
the nutrient level of the soil to gradually decrease
Strategies to improve soil health
 Undertake regular pH tests on soil to determine the
levels of acid present
 Add lime to the paddocks to help lower the pH level
and to counteract high acid levels
 Retaining crop stubble. Stubble that is retained helps
to mulch the soil, which is then able to retain more
moisture. It also assists in preventing wind erosion,
and nutrients contained in the stubble are returned to
the soil.
 Crop rotation: reduces weed and pest problems and
builds up the nutrient levels in the soil
Case study 11.1
 Read case study ‘ Growing lentils’ on pg 196 of your
text book and answer Q 1-7
Organic Farming
 Organic food is produced without the use of artificial
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chemicals
They are produced, processed, packaged and
transported without the use of herbicides, pesticides,
fungicides and fertilisers
Not treated with preservatives, hormones, chemicals
or other products
Cannot use GM organisms in any stage of their
production
Organic foods are sold through specialist natural food
shops and fresh food markets.
Organic certification
 ‘ Certified organic’ means a product has been
produced in accordance with a organic standard
established by a certifying agency
 Annual inspections- a farmer has to show strategies
they use for soil management, crop rotations, weed
control, pest and disease management, windbreaks,
biodiversity, animal health and water management
 It takes three years to change over from regular
farming practices to certified organic production , but
farmers are still able to sell their food.
Organic food products
 Most popular organic products: baby food, organic
meat and poultry, eggs, fresh fruit and vegetables and
dairy products. Along with some breakfast cereals,
wheat flours, chocolate and coffee.
Benefits to the producer
 Sustainable practices: crop rotation, improve soil
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fertility, reduces impact of pests and weeds
Livestock can be raised in a stress-reduced
environment without the use of growth hormones or
antibiotics
Traditional seed varieties helps to preserve the range
of crops for future generations
Rigorous audit systems
Crop yields can be stabilised and increased
Benefits to the consumer
 Provide health benefits
 Tastes better than non-organic produce
 Provides security that the food is not GM
 Contains fewer artificial ingredients and lower
chemical residues
Benefits to the environment
 Artificial pesticides and herbicides are prohibited
 Prevent salination and soil erosion and improve the
ability of the soil to take up and retain water are
implemented
 Organic fertilisers and natural methods are used to
reduce insect infestation and control weeds
 Non-renewable resources is minimised so organic
fertilisers can be produced from organic waste from
the farm
 Biodiversity is maintained