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