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 Croplands- 77% 2) Rangelands-16% 3)Ocean Fisheries- 7%

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? 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 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 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 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

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 Farm Act (1985) 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? 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