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

Monocultures of high-yield key crops

1. Rice, wheat, and corn

Large amounts of fertilizers, pesticides, water
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