APHG Unit 5 Agriculture

Okay, here are bulleted notes summarizing the provided article on the environmental consequences of agricultural practices:

• Overview: All agricultural practices impact the environment, and overuse of farmlands and water resources leads to negative consequences.

• Key Effects: Pollution, land cover change, soil salinization, and land degradation (desertification).

• Pollution:

  • Runoff from fields contains chemicals (pesticides, fertilizers), nutrients (nitrates), and bacteria.
  • Nitrates promote excessive plant growth and low oxygen levels in water bodies, damaging habitats.
  • Example: Gulf of Mexico “dead zone” caused by nutrient pollution.

• Land Cover Change:

  • Humans alter the Earth’s surface for agriculture.
  • Consequences can be difficult to remedy.
  • Terraced Farming:
    • Used on steep slopes.
    • Can lead to groundwater saturation
    • Requires constant maintenance to prevent soil erosion and mudslides.
  • Deforestation (Slash and Burn):
    • Poor farming practices can contribute to deforestation.
    • Clearing land before it recovers damages the environment.
    • Impacts wildlife habitat, leading to endangered species or extinction.
    • Example: Amazon rainforest fires in 2019, exacerbated by deforestation, may impact climate change.

• Soil Salinization:

  • Water-soluble salts build up in the soil, especially in arid/semi-arid regions.
  • Occurs when evaporation exceeds water replenishment.
  • Salt accumulation hinders plant water uptake, reducing crop yields.
  • Excessively saline irrigation water worsens the problem.
  • Example: Egypt faces soil salinity issues due to irrigation and saline drainage water.

• Desertification:

  • Permanent land degradation resulting from water consumption exceeding replenishment.
  • Causes: Overgrazing (pastoral nomadism or stationary herds), deforestation, clearing land for habitation.
  • Most vulnerable areas: Low or variable rainfall regions.
  • Impacts: Harms food supplies and endangers health due to dust.
  • Example: One-third of farmland in India is affected.
  • UN reported desertification is occurring at 30 to 35 times the historical rate.