Transcript Sustainable Agriculture - George Washington High School

Sustainable Agriculture
IB Geography II
Objective
• By the end of this lesson, students will be able
to examine the concept of sustainable
agriculture in terms of energy efficiency ratios
and sustainable yields
Starting Activity
• Take the
next two
minutes to
read the
following
excerpt.
• Then
answer this
question: Is
sustainable
farming
possible?
Sustainability rests on the principle that we
must meet the needs of the present without
compromising the ability of future
generations to meet their own needs.
Therefore, stewardship of both natural and
human resources is of prime importance.
Stewardship of human resources includes
consideration of social responsibilities such as
working and living conditions of laborers, the
needs of rural communities, and consumer
health and safety both in the present and the
future. Stewardship of land and natural
resources involves maintaining or enhancing
this vital resource base for the long term.
Sustainability
• Sustainability is a
relatively
straightforward
concept to define but
is harder to achieve.
Think of it as a three
legged stool. The stool
needs all three legs to
remain standing
Sustainable Agriculture
• This term refers to the ability of a farm to
produce food indefinitely, without causing
irreversible damage to ecosystems.
• Sustainable farming reduces or prevents
environmental degradation (depletion of
vegetation loss of biodiversity, soil and water)
Key Ideas with Sustainable Agriculture
• Conservation and soil health
• Nutrient recycling e.g. animal waste being
used for fertilizer
• Biodiversity – this is helped through a minimal
use of chemicals on the land
• Animal welfare – more care taken with
animals, and different diets perhaps
• Fair wages and treatment for workforce – farm
is part of the rural community
Sustainable Yield
• Instead of pushing for the
maximum yield from the
land, these farms look to
produce the sustainable
yield (the food that can
be taken from the land
without reducing the
ability of the land to
produce the same in
future without external
support).
The Environmental Costs of Increasing
Food Production
• Increasing food production has brought a
greater reliance on mechanization and the use
of artificial inputs such as fertilizer, pesticides
and Energy Subsidies (sources of energy not
directly received from the sun; eg: fossil
fuels)
• Degradation: depletion of vegetation, loss of
biodiversity, soil and water.
Agribusiness
• Profit maximization requires economies of
scale: when more goods can be produced on
a larger scale with lower costs, economies of
scale is said to be achieved
• With agribusiness, farming operations have
been taken over by big businesses who are
generally more concerned with profits and
less concerned with the environment.
Increasing Livestock Yield
• Selective breeding
• The use of antibiotics
• Restriction of movement
Factory Farming
• Also called “intensive livestock production”
• May cause eutrophication (an ecosystem
response to the agricultural run-off carrying
fertilizers of nearby water)
Eliminating Competitors
• Pesticides and Insecticides
• Can damage ecosystems
and the environment
• They are nonbiodegradable, and have
the tendency to
bioaccumulate in food
chains with serious
implications for humans.
• Bioaccumulation refers to
the accumulation of
substances, such as
pesticides, or other organic
chemicals in an organism
Maintaining Soil Health
• One of the simplest ways of maintaining soil
health is to rotate the crops (growing
alternative crops on land from year to year)
• The search for increasing profits can lead to
some farmers taking less care with the soil
– The Dust Bowl example
Reducing Biodiversity
• Intensive Commercial Farming: requires the
area under cultivation to be increased by
large-scale deforestation.
Deforestation
• The removal of trees may lead to:
– an increase albedo (the reflectivity of the ground
surface
– An increase diurnal (24 hour) temperature range
– Agrosystems (agricultural ecosystem) may lack
diversity
Food Miles
• The distance that food
travels from where it
is produced to where
it is consumed.
• A way of indicating the
environmental impact
of the food we eat
Energy Efficiency Ratios
• (EER) is a measure of the amount of energy
input into a system compared with the
output.
• Energy outputs/energy inputs
• Outputs should be more.
• An efficient farming system has an EER equal
to or greater than 1.
EER
• Inputs
–
–
–
–
–
–
–
–
Labor
Machinery
Vehicle fuel
Fertilizers
Seeds
Irrigation
Pesticides
Electricity
• Outputs
– Crop yields
Farm Welfare
• This is of increasing
importance to consumers.
– Sales of food considers
animal welfare
– Local sourcing
– organic free-range foods
– Fair trade
• But… there is often a high
price.