5.10 sg

Overview of Chapter 10: Farming – Conventional and Sustainable Practices

• Exploration of farming practices, resource management, and environmental implications.

Resources for Agriculture

• Agricultural lands:

  • Some are depleted in decades, while others sustain for centuries.

  • Farming practices can lead to degradation or restoration of resources.

• Important soil types:

  • Mollisols and Alfisols dominate US farming soils.

Ways We Use and Abuse Soil

• 11% of Earth's land is in agricultural production.

• Ecological impacts of conversion:

  • Loss of biodiversity and clean water.

  • Providing ecological services through grasslands and forests.

Arable Land Distribution

• Uneven distribution globally, with optimal conditions in moderate climates.

• Agricultural production increases through:

  • Fertilization

  • Pesticides

  • Irrigation

  • Not due to more land.

Soil Erosion Causes

• Major causes of soil loss:

  • Water and wind erosion.

  • Types of water erosion include:

    • Sheet Erosion: removal of thin soil layer.

    • Rill Erosion: small water channels form.

    • Gully Erosion: larger channels formed from rills.

    • Stream Bank Erosion: washing away of soil from banks.

Wind Erosion and Desertification

• Wind can match or exceed water as an erosive force, especially in dry areas.

• Desertification occurs from:

  • Row crops leaving soil exposed.

  • Weed-free fields and lack of crop rotation.

  • Continued monoculture increasing soil loss.

Agricultural Water Use

• Water is crucial for plant growth.

• Agriculture is the largest global user of water:

  • Significant losses through seepage and evaporation.

  • Issues include waterlogging and salinization.

Nutrient Needs in Agriculture

• Essential nutrients for plants:

  • Nitrogen, phosphorus, and potassium are often limiting.

  • Fertilizer usage increased from 20 kg/ha in 1950 to ~100 kg/ha in 2017.

  • Overuse leads to water pollution; alternatives include manure and nitrogen-fixing bacteria.

Energy Intensity of Farming

• Fossil fuel dependency increased since the 1920s with tractors and synthetic fertilizers post-WWII.

• Food often travels 2,400 km from farm to consumer, encouraging local eating.

Pest Management: Pesticides

• Biological pests compete with agriculture.

• Types of pesticides:

  • Biocides (broad-spectrum)

  • Herbicides (kill plants)

  • Insecticides (kill insects)

  • Fungicides (kill fungi)

• Modern agriculture relies on synthetic pesticides.

Historical Context of Pesticide Use

• DDT marked the beginning of synthetic pesticide usage in 1939.

• Initial benefits followed by environmental warnings:

  • Rachel Carson's "Silent Spring" raised awareness leading to the DDT ban in the US by the late 1960s.

Pesticides and Environmental Impact

• Non-target species affected by broad pesticide use (e.g. honey bees).

• Pest resurgence: surviving pests develop resistances, necessitating new pesticides.

Persistent Organic Pollutants (POPs)

• Stable and toxic chemicals like DDT that bioaccumulate in food chains.

• Movement to ban POPs led to a global treaty in 2001.

Human Health Issues Related to Pesticide Use

• WHO statistics indicate significant pesticide exposure in agricultural workers.

• Long-term effects unclear but potentially severe (cancer, immune issues, etc.).

• Residual pesticides in food are widespread.

Organic and Sustainable Agriculture

• Studies indicate organic practices are more eco-friendly and health-promoting.

• Current trends show under 1% of American farmland is organic; however, the market is growing.

• Criteria for organic farming:

  • No synthetic additives, hormones, or antibiotics.

Addressing Pest Management in Sustainable Farming

• Integrated Pest Management (IPM): a flexible strategy combining various techniques to manage pests effectively while minimizing pesticide use.

• Alternatives include:

  • Crop rotation

  • Mechanical cultivation

  • Biological controls.

Soil Conservation Methods

• Effective soil conservation techniques:

  • Contour plowing

  • Strip farming

  • Terracing: shaping land for water retention.

  • Inclusion of ground cover crops to mitigate erosion.

Role of Consumers

• Dietary choices impact environmental sustainability:

  • Vegetarian diets reduce energy inputs.

  • Locavore initiative encourages seasonal, local eating.

  • Community-supported agriculture (CSA) promotes local farming support.

Food Labeling Insights

• Understanding organic labels:

  • Different certification levels exist, from "100% organic" to "made with organic ingredients."

  • Ambiguity in terms like "natural" or "free-range" can mislead consumers, often lacking clear regulations.