Environmental Science Land Use and Soil 1 — Questions and Answers
Question 1: What is soil horizonation, and what does the 'O horizon' represent?
- Vertical layering of soil; bedrock layer
- Vertical layering of soil; organic matter / surface litter (Correct answer)
- Chemical zonation; oxidized minerals
- Biological zonation; root zone
Correct answer: Vertical layering of soil; organic matter / surface litter
Soil horizons are distinct layers, and the O horizon is the topmost layer composed of decomposing organic matter and litter.
Question 2: Which agricultural practice involves growing different crops in adjacent strips to reduce erosion and improve soil health?
- Monoculture
- Strip cropping (Correct answer)
- Slash and burn
- No-till farming
Correct answer: Strip cropping
Strip cropping alternates strips of row crops with grass or grain, reducing wind and water erosion and improving soil structure.
Question 3: What is desertification?
- Conversion of wetlands to desert ecosystems
- Degradation of dryland areas due to human activity and drought (Correct answer)
- Coastal erosion from sea level rise
- The spread of invasive desert plants
Correct answer: Degradation of dryland areas due to human activity and drought
Desertification is the process by which productive land in arid and semi-arid regions degrades into desert due to overgrazing, deforestation, and drought.
Question 4: Which soil property describes its ability to hold water against drainage?
- Porosity
- Permeability
- Field capacity (Correct answer)
- Bulk density
Correct answer: Field capacity
Field capacity is the amount of soil moisture held after excess water has drained away, representing available water for plants.
Question 5: What does the Dust Bowl of the 1930s illustrate about land management?
- The danger of excessive irrigation
- The consequences of drought alone
- The effects of poor soil conservation practices on agriculture (Correct answer)
- The impact of urban sprawl on farmland
Correct answer: The effects of poor soil conservation practices on agriculture
The Dust Bowl resulted from deep plowing and removal of native grasses on the Great Plains, which left topsoil vulnerable to wind erosion.
Question 6: Which land use change is the leading cause of tropical deforestation globally?
- Urban expansion
- Agricultural conversion (especially cattle ranching and soy) (Correct answer)
- Logging for timber
- Mining operations
Correct answer: Agricultural conversion (especially cattle ranching and soy)
Agricultural expansion — particularly for cattle pasture and soy cultivation — drives the majority of tropical forest clearing worldwide.
Environmental Science Land Use and Soil 1
What is soil horizonation, and what does the 'O horizon' represent?