Agricultural Practices, Sustainability, and Impacts

Agriculture and Land Use

  • Cultivated Land
    • Covers about 9% of Earth’s surface.
    • Responsible for about 14% of global biomass.
    • 46% of US virgin forest has been converted to farmland (~256 million acres).

Types of Agriculture

  • Alley Cropping

    • Involves planting crops alongside rows of trees or shrubs.
    • Benefits:
    • Increases biodiversity.
    • Decreases runoff and soil erosion.
    • Improves soil nutrient utilization.
    • Modifies microclimates for better crop production.
    • Provides wildlife habitat.

  • Conservation Tillage

    • Leaves 30% of crop residue on the soil surface.
    • Benefits:
    • Slows runoff.
    • Reduces erosion.

  • No-Till Farming

    • Seeds are injected into slits in soil.
    • Advantages:
    • Minimizes soil disturbance.
    • Reduces erosion and evaporation.
    • Low energy consumption.
    • Needs herbicides for weed control.

  • Contour Farming

    • Uses row patterns running level around hills to reduce water movement and erosion.

  • Terracing

    • Creates steep leveled steps on hilly terrain.
    • Reduces erosion and runoff, suitable for irrigation-heavy crops like rice.

  • Intercropping

    • Growing multiple crops in the same field, often to minimize erosion and runoff.

  • Interplanting

    • Growing two different crops simultaneously with similar nutrient requirements.

  • Crop Rotation

    • Involves rotating different crops year to year to prevent soil nutrient depletion.
    • Usually alternates nitrogen-depleting crops (e.g., corn) with nitrogen-fixing legumes (e.g., soybeans).

  • Monoculture vs. Polyculture

    • Monoculture: Cultivation of a single crop, which depletes soil nutrients, increases pest vulnerability.
    • Polyculture: Mimics natural ecosystem diversity, includes crop rotation, intercropping, etc.

  • High-Input vs. Low-Input Agriculture

    • High-Input Agriculture: Involves machinery, chemical fertilizers, and pesticides.
    • Low Input Agriculture: Uses hand tools and natural fertilizers, with limited irrigation.

  • Subsistence Farming

    • Aims for survival, with few crops sold commercially; typically organic due to reduced industrial inputs.

  • Organic Farming

    • Excludes synthetic fertilizers, pesticides, and GMOs; relies on natural cultivation methods.
    • Strategies include crop rotation and compost use to maintain productivity.

  • Farm to Table

    • Direct sale of food to consumers, minimizing transportation needs and supporting local economies.

  • Industrial Agriculture

    • Large-scale high-input farming focusing on maximizing productivity and profit.

  • Plantation Farming

    • Commercial agriculture in tropics focused on export, often harming local ecosystems.

Sustainability in Agriculture

  • Sustainability Definition: Capacity of Earth's systems to thrive and adapt long-term.

Use of Fertilizers

  • Inorganic Fertilizers

    • Made from mined or synthetic minerals; mainly nitrogen, phosphorus, potassium.
    • Premiums: Fast uptake but devalue soil health over time.

  • Organic Fertilizers

    • Derived from plant or animal sources (e.g., compost, manure).
    • Benefits:
    • Improves soil structure and quality.
    • Maintains soil organisms necessary for health.
    • Biodegradable.

Genetically Modified Organisms (GMOs)

  • Definition: Organisms with altered genetic material.
  • Growth Statistics: Major crops (e.g., 94% soybeans, 96% cotton, 93% corn in the US) are GMOs.
  • Advantages:
    • Reduced pesticide need.
    • Higher yields and more shelf-stable produce.
    • Crops developed for extreme conditions.
  • Concerns: Unknown long-term impacts on human health and environment.

Agricultural Productivity

  • Enhanced based on efficiency and resource availability.
    • Example: Milk production rose 250% per cow from 1950-2000 through hormones.
    • GMO-enhanced corn yields increased 300% during the same period.
  • Productivity concerns: Related to sustainability, safety, and pollution.

Irrigation Systems

  • Essential for crop growth in inconsistent climates.

  1. Drip Irrigation

    • Water drips into soil through tubes; ideal for high-value crops.

  2. Sprinkler Irrigation

    • Fine spray of water to specific areas; efficient and cost-effective.

  3. Center Pivot Irrigation

    • Self-rotating system with a main pipe; covers larger areas.

  4. Furrow Irrigation

    • Channels filled with water; suitable for row crops.

  5. Terraced Irrigation

    • Stepped design for water management in hills; retains soil nutrients.

Pesticide Use and Risk Management

  • Pest Control
    • Different types of pests (rodents, insects, fungi).
    • Pesticide Types: Biological, organophosphates, inorganic, carbamates.
  • Integrated Pest Management (IPM)
    • Combines various methods to control pests sustainably.
    • Aims to keep pest populations at acceptable levels without eradicating them.

Sustainable Agriculture Practices

  • Focus on eco-friendly production and distribution.
    • Strategies:
    • Efficient water use.
    • Diverse farming to mitigate risks associated with monoculture.