1. How is Food Produced?

2. 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

3. Agricultural Revolution
The Agricultural Revolution took place 10,000 years ago
Croplands- 77% 2) Rangelands-16%
3)Ocean Fisheries- 7%

4. Three most important crops (feeds 2/3 of the world)
Wheat
Rice
Corn
These crops provide
more than half the
calories people consume

5. 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!

6. How has the Green Revolution Increased Food Production?
Develop and plant monocultures cultivation of single crops
Produce high yields by using large inputs of fertilizers, pesticides, and water
Multiple cropping

7. How serious is soil erosion?
Soil is being eroded faster than it is being formed
Water
Wind
people

8. Soil Erosion (cont’d) Nature’s Lesson: Dust Bowl of 1930s
Bad cultivation technique and drought

9. 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

10. Terracing
Reduces soil erosion on steep slopes by series of broad terraces that run across land contour

11. 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.

12. Alley Cropping
Several crops are planted together in strips between alleys of trees and shrubs

13. Windbreaks
Reduces wind erosion and provides habitat for birds, pest eating and pollinating insects, and animals.

14. Conservation-Tillage Farming
To disturb the soil as little as possible while planting
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

15. How can we maintain and restore soil fertility?
Organic Fertilizer
Animal manure
Green manure
Compost
Crop rotation: corn→ soybeans (legumes)→ oats→ alfalfa (legumes)

16. 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

17. GOOD NEWS
Farm Act (1985)
Farmers received subsides for planting eroded land with soil saving grass or trees for 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

18. Decrease in Soil Erosion

19. 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

20. 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