Core Case Study: Organic Agriculture Is on the Rise

• Organic agriculture: Crops are grown without using synthetic pesticides, synthetic inorganic fertilizers, or genetically engineered seeds

  • Uses no genetically modified seeds

  • Regionally and locally oriented

  • Produces less air and water pollution

  • Crop rotation and biological pest control

• Animals are grown without using antibiotics or synthetic hormones

• U.S. in 2008

  • 0.6% cropland; 3.5% food sales

Industrialized Agriculture

• Industrialized Agriculture: Use synthetic inorganic fertilizers and sewage sludge to supply plant nutrients.

  • Makes use of synthetic chemical pesticides

  • Uses conventional and genetically modified seeds

  • Depends on nonrenewable fossil fuels (mostly oil and natural gas)

  • Produces significant air and water pollution and greenhouse gases

  • Is globally export-oriented

What Is Food Security and Why Is It Difficult to Attain?

Many People Have Health Problems Because They Do Not Get Enough to Eat

• Food security: All or most people in a country have daily access to enough nutritious food to lead active and healthy lives

• Food insecurity: Chronic hunger and poor nutrition is caused by poverty, political upheaval, war, corruption, and bad weather

What Nutrients Do Humans Need?

• Macronutrients: Carbohydrates, proteins, and fats

• Micronutrients: Vitamins and minerals

Chronic Hunger & Famine

• Chronic malnutrition→ deficiency of protein & nutrients

• 1 in 6 people in less-developed countries is chronically undernourished or malnourished

• Famine: Drought, flooding, war, and other catastrophes

Many People Have Health Problems from Eating Too Much

• Overnutrition: Excess body fat from too many calories and not enough exercise

• Similar health problems to those who are underfed

  • Lower life expectancy

  • Greater susceptibility to disease and illness

  • Lower productivity and life quality

How Is Food Produced?

Food Production Has Increased Dramatically

• Three systems produce most of our food

  • Croplands

    • 77% of 11% world’s land area

  • Rangelands, pastures, and feedlots

    • 16% of 29% of the world’s land area

  • Aquaculture

    • 7%

Industrialized Crop Production Relies on High-Input Monocultures

• Industrialized agriculture, high-input agriculture

  • Heavy equipment

  • Financial capital

  • Fossil fuels

  • water

  • inorganic fertilizers

  • pesticides

• The goal is to steadily increase crop yield

  • Plantation agriculture: cash crops (bananas, soybeans, sugarcane, etc). Primarily in less-developed countries

  • Increased use of greenhouses to raise crops

• Hydroponics: growing plants in nutrient-rich water solutions rather than soil

Traditional Agriculture Often Relies on Low-Input Polycultures

• Traditional subsistence agriculture: Human labor and draft animals for family food

• Traditional intensive agriculture: Higher yields through the use of manure and water

• Polyculture: Benefits over monoculture

• Slash-and-burn agriculture: Subsistence agriculture in tropical forests. Clear and burn a small plot. Grow many crops and reduce soil erosion. Less need for fertilizer and water

Soil Formation and Generalized Soil Profile

• Layers (horizons) of mature soils

  • O horizon: leaf litter

  • A horizon: topsoil

  • B horizon: subsoil

  • C horizon: parent material, often bedrock

A Closer Look at Industrialized Crop Production

• Green Revolution: increase crop yields

1. Monocultures of high-yield key crops

   1. Rice, wheat, and corn

2. Large amounts of fertilizers, pesticides, water

3. Multiple cropping

• Second Green Revolution: Fast-growing dwarf varieties

Case Study: Industrialized Food Production in the United States

• Agribusiness

  • The average farmer feeds 129 people. Annual sales greater than auto, steel, and housing combined

• Food production: very efficient. Americans spend 10% of their income on food

• Hidden costs of subsidies and costs of pollution and environmental degradation

Meat Production and Consumption Have Grown Steadily

• Animals for meat raised in

  • Pastures and rangelands

  • Feedlots

• Meat production increased fourfold between 1961 and 2007

  • Increased demand for grain

  • Demand is expected to go higher

What Environmental Problems Arise from Food Production?

Natural Capital Degradation: Food Production

• Biodiversity Loss

  • Loss and degradation of grasslands, forests, and wetlands

  • Fish killed from pesticide runoff

• Soil

  • Erosion

  • Loss of fertility

  • Desertification

• Water

  • Water waste

  • Aquifer depletion

  • Increased runoff, sediment pollution, and flooding from cleared land

• Air Pollution

  • Emissions of greenhouse gas

• Human Health

  • Nitrat6es in drinking water

  • Pesticide residue on food, water, and air

  • Bacterial contamination of meat

Topsoil Erosion Is a Serious Problem in Parts of the World

• Soil erosion: Movement of soil by wind and water

  • Natural causes

  • Human causes

• Two major harmful effects of soil erosion

  • Loss of soil fertility

  • Water pollution

Excessive Irrigation Has Serious Consequences

• Salinization: Gradual accumulation of salts in the soil from irrigation water

  • Lowers crop yields and can even kill plants

  • Affects 10% of world croplands

• Waterlogging: Irrigation water gradually raises the water table

  • Can prevent roots from getting oxygen

  • Affects 10% of world croplands

Animal Feedlots

• Advantages

  • Increased meat production

  • Higher profit

  • Less land use

  • Reduced overgrazing

  • Reduced soil erosion

  • Protection of biodiversity

• Disadvantages

  • Large inputs of grain, fish meal, water, and fossil fuels

  • Greenhouse gas emissions

  • Animal waste can pollute water

  • Increase of genetic resistance to microbes in humans

Aquaculture

• Advantages

  • High efficiency

  • High yield

  • Low fuel use

  • High profits

• Disadvantages

  • Large inputs of land, feed, and water

  • Waste output

  • Loss of mangrove forests and estuaries

How Can We Protect Crops from Pests More Sustainably?

Nature Controls the Populations of Most Pests

• Pest

  • Interferes with human welfare

Pesticides

• Insecticides

• Herbicides

• Fungicides

• Rodenticides

• First-generation pesticides: Borrowed from plant

• Second-generation pesticides: Lab-produced products such as DDT and others

• David Pimentel: Pesticide use has not reduced U.S. crop loss to pests

  • 1942-1997→ crop losses from insects increased from 7% to 13%, even with a 10x increase in pesticide use

  • High environmental, health, and social costs with the use

  • Use alternative pest management practices

Conventional Chemical Pesticides

• Advantages

  • Save lives

  • Increase food supplies

  • Profitable

  • Work fast

  • Safe if used properly

• Disadvantages

  • Promote genetic resistance

  • Kill natural pest enemies

  • Pollute the environment

  • Can harm wildlife and people

  • Are expensive for farmers

Integrated Pest Management Is a Component of Sustainable Agriculture

• Integrated pest management (IPM): Chemical tools to reduce crop damage to an economically tolerable level. Reduces pollution and pesticide costs

How Can We Produce Food More Sustainably?

Reduce Soil Erosion

• Soil conservation, some methods

  • Terracing

  • Contour planting

  • Strip cropping with cover crop

  • Alley cropping, agroforestry

  • Windbreaks or shelterbelts

  • Conservation-tillage farming

    • No-till

    • Minimum tillage

Soil Salinization

• Prevention

  • Reduce irrigation

  • Switch to salt-tolerant crops

• Cleanup

  • Flush soil (expensive and wastes water)

  • Stop growing crops for 2-5 years

  • Install underground drainage systems

Organic Farming

• Improves soil fertility

• Reduces soil erosion

• Retains more water in the soil during drought years

• Uses about 30% less energy per unit of yield

• Lowers CO2 emissions

• Reduces water pollution by recycling livestock wastes

• Eliminates pollution from pesticides

• Increases biodiversity above and below ground

• Benefits wildlife such as birds and bats