5.4: Impact of Agriculture

Learning Objective: Describe agricultural practices that cause environmental damage

Essential Knowlege:

• Agricultural practices that can cause environmental damage include tilling, slash-and-burn farming, and the use of fertilizers

Monocropping:

• Growing one single species (corn, wheat, soy) of crop

• Benefits:

  • Highly efficient for harvest, pesticide, and fertilizer application

• Negatives:

  • Greatly decreases biodiversity (more prone to pests, fewer natural predators)

  • Increases soil erosion (crops harvested all at once & soil left bare)

  • Decreases habitat diversity for species living in the area

Tilling

• Mixing and breaking up soil to make planting easier

• Benefits:

  • Makes planting easier

  • loosens soils for roots

• Negatives;

  • Increases erosion by loosening topsoil, breaking up leftover root structure from harvest

  • Loss of organic matter & topsoil nutrients over time

  • Increased PM in the air (respiratory irritations) & sediments in nearby water (turbidity)

Slash & Burn

• Cutting down vegetation and burning it to clear land for Agriculture & return nutrients in plants to soil

• Negatives:

  • Deforestation

    • Loss of: Habitat, biodiversity, CO2 sequestration (storage), loss of air pollution filtration

  • Releases CO2, CO, N2O - all GHGs that lead to global warming

  • Increases PM in air (asthma)

  • Lowers albedo, making area warmer

Synthetic (inorganic) Fertilizer

• Negatives:

  • Don’t return organic matter to soil; no increased H2O holding capacity & no soil decomposers

  • Leaching: Water carries excess nutrients (nitrates & phosphates) into groundwater or into surface waters (as runoff)

    • Can contaminate groundwater for drinking

    • And can cause eutrophication of surface waters