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