5.4 - Impact of Agricultural Practices

Question 1

Monocropping

Answer 1

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

Pros
Highly efficient for harvest, pesticide and fertilizer application

Cons
- Greatly decreases biodiversity (more prone to pests, fewer nat. predators)
- Increases soil erosion (crops harvested all at once & soil left bare)
- Decreases habitat diversity for species living in the area

Question 2

Tilling

Answer 2

• Mixing and breaking up soil to make planting easier

pros
Also loosens soil for roots

Cons
- Increases erosion by loosening topsoil, breaking up leftover root structure from harvest
- Loss of organic matter & topsoil nutrients over time
- Increased PM in air (rerp. irr) and sediments in nearby water (turbidity)

Question 3

Slash and Burn

Answer 3

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

Cons
- Deforestation - Loss of: habitat, biodiv, 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

Question 4

Synthetic (inorganic) Fertilizers

Answer 4

Cons
- Don’t return organic matter to soil; no increased H2O holding cap. & no soil decomposers
- Leaching: water carries excess nutrients (nitrates & phosphates) into groundwater or into surface waters (as runoff)
- Contaminates groundwater for drinking
- Causes eutrophication of surface waters