PP

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