AP Environmental Science, AP exams, 10–15%

Unit 5: Land and Water Use

Unit 5 is the largest applied unit, covering agriculture, forestry, fishing, mining, and urbanization along with the sustainable alternatives to each. The tragedy of the commons frames the whole unit. Free-response questions here frequently ask you to name a practice, explain a consequence, and propose a specific solution.

Position: 5 of 9 units
Published weighting: 10–15% in the official framework
Topics covered: 6 topics in this guide

What is covered

Topics inside this unit.

These topics describe the scope students most often review for this part of AP Environmental Science. Treat them as a study checklist rather than an exhaustive list of what a single exam form can sample.

Tragedy of the commons: Why shared, unregulated resources are overused, and the policy responses that address it.
Agricultural practices and the Green Revolution: Mechanization, high-yield varieties, fertilizer and pesticide use, and their environmental trade-offs.
Irrigation and pest control methods: Drip, flood, furrow, and spray irrigation, salinization and waterlogging, and integrated pest management.
Forestry, fishing, and mining impacts: Clearcutting, overfishing and bycatch, surface and subsurface mining, and their ecological consequences.
Urbanization and ecological footprints: Impervious surfaces, urban runoff and heat islands, urban sprawl, and how footprints are estimated.
Sustainability practices: Sustainable agriculture, aquaculture, and forestry, plus green roofs and permeable pavement for runoff.

Study tips

How to practice Land and Water Use.

Section-specific guidance that follows from how this material is usually tested.

For every problem in this unit, memorize one specific, named solution; free-response rubrics reward specificity.
Build a practice-to-consequence table for agriculture so cause and effect are linked rather than listed.
Practice explaining a trade-off in both directions, since many questions ask for a drawback of a beneficial practice.

Where this fits

Unit 5: Land and Water Use is 5 of 9 units in the AP Environmental Science guide, and it carries a published weighting of 10–15% in the official framework. Use the full guide to balance it against everything else you have to review.

Back to the AP Environmental Science guide Official exam information

Sample Land and Water Use questions

Practice questions, not yet expert-reviewed

Original practice questions written to the published framework for this section. No expert has reviewed them, and they are not taken from any official exam. Try each one before you open the answer.

Question 1Foundational
What is the term for the overuse and degradation of a shared, unregulated resource by individuals each acting in their own interest?
1. AThe tragedy of the commons
2. BMaximum sustainable yield
3. CThe demographic transition
4. DIntegrated pest management
Show answer
Answer: A. The tragedy of the commons
Each user gains the full benefit of taking a little more while the cost of depletion is spread across everyone, so the rational individual choice destroys the shared resource. Ocean fisheries, shared groundwater, and the atmosphere are all classic examples. Maximum sustainable yield is the tempting distractor, but it names the harvest limit that avoids the tragedy rather than the problem itself.
Key insight: Private benefit with shared cost is the engine of the tragedy, which is why regulation or ownership is the usual fix.
Question 2Foundational
Which irrigation method delivers water slowly through tubing directly to the root zone and loses the least water to evaporation and runoff?
1. AFlood irrigation
2. BDrip irrigation
3. CFurrow irrigation
4. DSpray irrigation
Show answer
Answer: B. Drip irrigation
Drip irrigation applies water at low pressure right at the plant, so very little evaporates from the soil surface or runs off the field. Spray irrigation is the tempting distractor because it is more efficient than flooding, but throwing water through the air still loses a substantial share to evaporation and wind drift. Flood and furrow irrigation are the least efficient and also raise the risk of salinization and waterlogging.
Key insight: Efficiency rises as water spends less time in the air and lands closer to the roots.
Question 3Intermediate
What is the name for the buildup of mineral salts in the upper soil layers of a dry region after years of irrigation and evaporation?
1. AWaterlogging
2. BLeaching
3. CSalinization
4. DDesertification
Show answer
Answer: C. Salinization
Irrigation water always carries dissolved salts, and when it evaporates in an arid climate the water leaves but the salts remain and accumulate near the surface. Waterlogging is the tempting distractor because it comes from the same practice, but it describes saturated soil that starves roots of oxygen rather than salt accumulation. Salinized soil eventually becomes too saline for most crops, which is one route to abandoned farmland.
Key insight: Evaporation removes water and leaves solutes behind, so arid-region irrigation concentrates salt over time.
Question 4Intermediate
Which pest control approach combines crop rotation, biological controls, and carefully limited pesticide application to hold pest numbers below an economic threshold?
1. AMonocropping
2. BSlash-and-burn agriculture
3. CContour plowing
4. DIntegrated pest management
Show answer
Answer: D. Integrated pest management
Integrated pest management treats pesticides as one tool among several rather than the first response, which slows the evolution of pesticide resistance and reduces harm to pollinators and other nontarget species. Monocropping is the tempting distractor for anyone scanning for an agricultural term, but planting a single crop over large areas makes pest outbreaks more likely, not less. Contour plowing addresses soil erosion rather than pests.
Key insight: Integrated pest management aims to keep pests below a damage threshold, not to eliminate them.
Question 5Advanced
How do the impervious surfaces of a city change the way precipitation moves through the local watershed?
1. ASurface runoff increases while infiltration and groundwater recharge decrease
2. BInfiltration increases while surface runoff decreases
3. CBoth infiltration and groundwater recharge increase
4. DRunoff decreases because pavement holds water in place
Show answer
Answer: A. Surface runoff increases while infiltration and groundwater recharge decrease
Roofs, roads, and parking lots block water from soaking into soil, so a much larger fraction of each storm becomes fast-moving runoff that reaches streams within minutes. That raises flood peaks, carries oil, salt, and sediment into waterways, and starves aquifers of recharge. Permeable pavement, green roofs, and rain gardens are the standard engineered responses because each restores some infiltration.
Key insight: Paving a watershed converts slow groundwater recharge into fast, polluted stormwater.

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Unit 5: Land and Water Use