Transcript How is Food Produced?

How is Food Produced?
What are the environmental
effects of producing food?
Modern agriculture has a
greater harmful
environmental impact
than any other human
activity, and these
effects may limit future
food production
Agricultural Revolution
The Agricultural Revolution took place 10,000 years ago
1)
Croplands- 77%
2) Rangelands-16%
3)Ocean Fisheries- 7%
Three most important crops
(feeds 2/3 of the world)
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Wheat
Rice
Corn
These crops provide
more than half the
calories people consume
What Plants and Animals Feed
the World?
Out of 10,000 species of plants that have been
used for food only 14 plants and 8 animals
species provide 90% of global intake of
calories!
How has the Green Revolution
Increased Food Production?
Green Revolution:
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Develop and plant monocultures cultivation of
single crops
Produce high yields by using large inputs of
fertilizers, pesticides, and water
Multiple cropping
How serious is soil erosion?
Soil is being eroded faster
than it is being formed
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Water
Wind
people
Soil Erosion (cont’d)
Nature’s Lesson:
Dust Bowl of 1930s
Bad cultivation technique
and drought
Methods of Soil Conservation
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Using ways to reduce soil erosion and restore
soil fertility
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Terracing
Contour planting and strip cropping
Alley cropping or agro forestry
Windbreaks
Terracing
Reduces soil erosion on steep slopes by series of
broad terraces that run across land contour
Contour Planting and Strip
Cropping
Planting in rows across the slope of the land rather
than up and down. Each row acts as a small dam to
hold soil and slow water runoff.
Alley Cropping
Several crops are planted together in strips between
alleys of trees and shrubs
Windbreaks
Reduces wind erosion and provides habitat for birds,
pest eating and pollinating insects, and animals.
Conservation-Tillage Farming
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To disturb the soil as little as possible while planting
Advantages
 Disadvantages
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Reduces erosion
Saves fuel
Cuts costs
Holds more soil water
Allows several crops per
season
Does not reduce crop yields
Reduces CO2 release from
soil
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Can increase herbicide use
for some crops
Leaves stalks that can harbor
stalk pests and fungal
disease
Requires investment in
expensive equipment
How can we maintain and restore soil
fertility?
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Organic Fertilizer
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Animal manure
Green manure
Compost
Crop rotation: corn→
soybeans (legumes)→
oats→ alfalfa (legumes)
Can Inorganic Fertilizers Save The
Soil?
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Advantages
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Easy to transport, apply,
store
Inexpensive to produce
Help feed one in every three
people in the world
Without it food crop output
would drop 40%
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Disadvantages
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Does not add humus to soil
Reduces ability of soil to
hold water
Lowers oxygen content in
soil
Supplies only 2-3 of the 20
or so nutrients needed
Releases greenhouse gas
nitrous oxide(N2O)
Runoff can kill fish
GOOD NEWS
Farm Act (1985)
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Farmers received subsides for planting eroded
land with soil saving grass or trees for 10-15
years
Forgive all or part of farmer’s debts if they
agree not to farm erodible cropland/ wetlands
for 50 years
Erosion cut by 2/3
Decrease in Soil Erosion
How do we feed the world?
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Overnutrition: When food energy intake
exceeds energy use and causes excess body
fat
Undernutrition: Consuming insufficient food
to meet one’s minimum daily energy needs
Malnutrition: Deficiency of protein and other
key nutrients
How do we develop sustainable
agriculture?
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Good News! We produce more than enough food to meet the
basic nutritional needs of every person on the planet.
Produce more grain by reducing meat production
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Beef (7kg grain for 1kg of meat)
Pigs (4 kg)
Chicken (2.2 kg)
Fish ( 2 kg)
Top priority is the soil.
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Minimize erosion
Limit pesticide & fertilizer use (IPM & crop rotation)
Stop pollution & remediate soil & water