5.3 - The Green Revolution

Question 1

The Green Revolution

Answer 1

• Shift in agriculture away from small, family operated farms to large, industrial-scale agribusiness
  - Increased use of mechanization, GMOs, irrigation, fertilizers, and pesticides

Pros
- Greatly increases efficiency of lands, short-term profitability, and food supply
- Decreased world hunger and increased earth’s carrying capacity for humans

Cons
- Bring neg. Consequences (soil erosion, biodiversity loss, ground & surface water contamination)

Question 2

Mechanization

Answer 2

Pros
- Increased use of tractors for plowing and tilling fields, and combines for harvesting = increased yield + profits

Cons
- Increases reliance on fossil fuels (gasoline/diesel fuel)
- Emits GHGs to atmosphere → climate change
- Heavy machinery also compacts soil, decreasing H2O holding capacity
- Makes topsoil more prone to erosion

Question 3

GMOs

Answer 3

• Genetically modified crops have genes for drought tolerance, pest resistance, faster growth, and larger fruit/grain

pros
Increases profitability with fewer plants lost to drought, disease, or pests + larger plant size + yield/acre

Cons
- GMO crops are all genetically identical so gen. diversity is decreased and susceptibility to diseases or pest is increased

Question 4

Synthetic Fertilizer

Answer 4

• Shift from organic fertilizers (like manure and compost) to synthetic fertilizers (man made ammonium, nitrate, phosphate)

Pros
Increases yield and profits with more key nutrients needed for plant growth (N, P, K) added to the soil

cons
- Excess nitrate, phosphate are washed off fields and into nearby waters where they cause eutrophication (algae blooms)
- Require FFs for production, releasing CO2 (climate change)

Question 5

Irrigation

Answer 5

• Drawing water from the ground or nearby surface waters and distributing it on fields to increase plant growth

Pros
Make agriculture possible in many parts of the world that are naturally too dry (don’t receive enough rain)

Cons
- Can deplete groundwater sources, especially aquifers
- Over watering can drown roots (no O2 access) and cause soil salinization (increase salt level in soil)

Question 6

Pesticides

Answer 6

• Increase in use of synthetic pesticides - chemicals sprayed on crops that kill weeds, insects, rodents and other pests that eat or damage crops

Pros
Increases yield and profits with fewer plants lost to pests

Cons
- Can wash off crops in runoff and kill or harm non-target species in local soil or waters (bees especially)