AP Environmental Science Flashcards: Irrigation Methods
Written by AP Content Team, Verified for 2026 AP Exams, Last updated: May 2026
Review key ideas with interactive flashcards. This set includes 24 cards to help you master important concepts.
How does waterlogging inhibit plant growth?
Waterlogging raises the water table so that the soil is saturated, which inhibits a plant's ability to absorb oxygen through its roots.
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How does waterlogging inhibit plant growth?
Waterlogging raises the water table so that the soil is saturated, which inhibits a plant's ability to absorb oxygen through its roots.
What percentage of water is lost to evaporation and runoff in spray irrigation?
Spray irrigation is relatively efficient, losing one-quarter (25%) or less of its water to evaporation and runoff.
Compare the water loss of furrow irrigation versus flood irrigation.
Furrow irrigation is less efficient, losing about 1/3 (or ~33%) of its water, while flood irrigation loses about 20% of its water.
A farmer observes that their plants are yellowing and their roots appear to be rotting in soil that is constantly saturated. What irrigation-related problem is this?
This is a classic sign of waterlogging, where excess water in the soil prevents roots from getting the oxygen they need to survive.
What is flood irrigation?
Flood irrigation is a method where an entire field is covered with water. It is a common but relatively inefficient method.
What is drip irrigation?
Drip irrigation is a method that uses hoses with small holes to deliver water slowly and directly to plant roots. It is the most efficient irrigation method.
What is a major environmental consequence of overusing aquifers for irrigation?
Aquifers can be severely depleted if overused for agricultural irrigation. The Ogallala Aquifer is a prominent example of this issue.
Define: Salinization
Salinization is the process where salts remain in the soil after irrigation water evaporates, which can eventually make the soil toxic to plants.
What are the main drawbacks of furrow irrigation?
Furrow irrigation is inefficient, losing about one-third of the water to evaporation and runoff, though it is very inexpensive to implement.
What is spray irrigation?
Spray irrigation is a method where water is pumped through nozzles and sprayed across a field, similar to a sprinkler. It is more efficient than flood or furrow methods.
Which two irrigation methods are noted as being expensive?
Spray irrigation and drip irrigation are both described as being more expensive than flood or furrow methods.
A farmer in an arid region notices a white crust forming on the soil after years of irrigation. What environmental problem is occurring?
This is an example of salinization, where salts are left behind in the soil as the irrigation water evaporates, eventually becoming toxic to plants.
Which irrigation method is most likely to cause waterlogging?
Flood irrigation is explicitly mentioned as a method that can lead to waterlogging of the soil.
A farmer with a large, flat field and a very limited budget needs to irrigate. Which two methods are most likely choices, and what is their shared drawback?
The farmer would likely choose furrow or flood irrigation because they are inexpensive. Their shared drawback is significant water loss to evaporation and runoff.
Which irrigation method requires a significant energy input?
Spray irrigation requires energy to operate the pumps that move water through the system.
Define: Waterlogging
Waterlogging occurs when too much water sits in the soil, raising the water table and preventing plants from absorbing oxygen through their roots.
What is the largest human use of freshwater?
The largest human use of freshwater is for irrigation, accounting for 70% of total use.
What are the main drawbacks of flood irrigation?
Flood irrigation loses about 20% of its water to evaporation and runoff and can lead to waterlogging of the soil.
Rank the four main irrigation types from most efficient to least efficient.
The ranking from most to least efficient is: Drip (~5% loss), Spray (≤25% loss), Flood (~20% loss), and Furrow (~33% loss).
What is furrow irrigation?
Furrow irrigation involves digging trenches or 'furrows' between rows of crops and filling them with water. It is an inexpensive method.
What are the main drawbacks of spray irrigation?
Although more efficient than flood or furrow methods, spray irrigation is more expensive and requires energy to run the pumps.
What is the primary drawback of drip irrigation?
Despite being the most efficient method with only 5% water loss, drip irrigation is expensive and therefore not often used on a large scale.
Why might a farmer choose furrow irrigation despite its high water loss?
A farmer might choose furrow irrigation because it is very inexpensive to set up and operate compared to more efficient methods like spray or drip irrigation.
A farmer is growing a high-value crop and wants to minimize water waste. Which irrigation method is the best choice, despite its high initial cost?
Drip irrigation would be the best choice, as it is the most efficient method, losing only about 5% of its water.