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
1) Croplands- 77% 2) Rangelands-16%
3)Ocean Fisheries- 7%
The Agricultural Revolution took place 10,000 years ago
Three most important crops (feeds 2/3 of the world)
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:1. Develop and plant monocultures cultivation of
single crops
2. Produce high yields by using large inputs of fertilizers, pesticides, and water
3. Multiple cropping
How serious is soil erosion?
Soil is being eroded faster than it is being formed
Water Wind people
Soil Erosion (cont’d)Nature’s Lesson:
Dust Bowl of 1930s
Bad cultivation technique and drought
Methods of Soil Conservation
Using ways to reduce soil erosion and restore soil fertility 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 CroppingSeveral crops are planted together in strips between
alleys of trees and shrubs
WindbreaksReduces wind erosion and provides habitat for birds, pest eating and pollinating insects, and animals.
Conservation-Tillage Farming
Advantages 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
Disadvantages Can increase herbicide use
for some crops Leaves stalks that can
harbor stalk pests and fungal disease
Requires investment in expensive equipment
To disturb the soil as little as possible while planting
How can we maintain and restore soil fertility?
Organic Fertilizer Animal manure Green manure Compost Crop rotation: corn→
soybeans (legumes)→ oats→ alfalfa (legumes)
Can Inorganic Fertilizers Save The Soil?
Advantages 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%
Disadvantages 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
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
Farm Act (1985)
Decrease in Soil Erosion
How do we feed the world? 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? 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
Beef (7kg grain for 1kg of meat) Pigs (4 kg) Chicken (2.2 kg) Fish ( 2 kg)
Top priority is the soil. Minimize erosion Limit pesticide & fertilizer use (IPM & crop rotation) Stop pollution & remediate soil & water
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