Chapter 12: Food, Soil, and Pest Management

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

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