CCA Irrigation Management and Water Use 3

Question 1

Irrigation application efficiency is calculated as:

Accepted Answer

Volume of water stored in the root zone divided by the total volume applied, expressed as a percentage

Answer

Application efficiency measures what fraction of the water applied actually reaches and is stored in the crop root zone for use, with losses from runoff, deep percolation, and evaporation reducing efficiency.

Question 2

Distribution uniformity (DU) of an irrigation system is measured primarily by:

Accepted Answer

Collecting catch-can measurements across the irrigated area and comparing the low-quarter average to the mean application depth

Answer

DU uses catch-can or flow-meter data to compare the average of the lowest 25% of application amounts to the overall mean, with higher DU values (closer to 1.0) indicating more uniform water coverage.

Question 3

Which of the following best describes the purpose of a pressure regulator installed on center-pivot or drip irrigation systems?

Accepted Answer

To maintain consistent operating pressure at each emitter or nozzle regardless of elevation or line pressure variation

Answer

Pressure regulators maintain a consistent, designed operating pressure at each emitter or sprinkler head, preventing over- or under-application caused by pressure variations along the lateral or from inlet pressure fluctuations.

Question 4

In furrow irrigation, surge flow is used primarily to:

Accepted Answer

Improve water advance rate and distribution uniformity by cycling flow on and off

Answer

Surge irrigation cycles water flow on and off in timed pulses, causing soil at the wetting front to temporarily seal, which accelerates subsequent water advance and improves distribution uniformity compared to continuous flow.

Question 5

The primary environmental concern associated with over-irrigation in agricultural fields is:

Accepted Answer

Leaching of nitrates and other soluble nutrients into groundwater

Answer

Over-irrigation drives water below the root zone, carrying soluble nitrates and other nutrients into groundwater, contributing to drinking water contamination and aquatic ecosystem degradation.

(CCA) Certified Crop Advisor Practice Test

(CCA) Certified Crop Advisor Practice Test

CCA Irrigation Management and Water Use 3