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

Volume of water pumped divided by the crop's peak ET demand

Answer

Total annual precipitation divided by crop water use

Answer

Discharge rate of the pump divided by total field acreage

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

Calculating the ratio of maximum to minimum application depths across a field

Answer

Measuring the pumping pressure at the mainline supply point

Answer

Counting the number of sprinkler heads operating simultaneously

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

To increase water pressure to overcome elevation differences across a field

Answer

To filter sediment and bacteria from the irrigation water supply

Answer

To measure the total flow volume delivered to the field

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

Flush salts from the soil surface before planting

Answer

Prevent furrow erosion by reducing peak flow velocity

Answer

Aerate the soil between irrigation events

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

Reduction in atmospheric humidity near the field

Answer

Increased weed seed germination at the soil surface

Answer

Excessive shading from lush crop canopies reducing solar radiation

Question 6

A crop advisor recommends converting a field from flood irrigation to subsurface drip irrigation. The most significant expected benefit is:

Accepted Answer

Substantially reduced water use and improved water application efficiency

Answer

Lower initial capital investment compared to flood irrigation infrastructure

Answer

Elimination of the need to monitor crop water status

Answer

Increased soil microbial activity due to more frequent wetting events

Question 7

When conducting an irrigation water quality test, which two parameters are most critical for assessing salinity and sodium hazard to crops and soil structure?

Accepted Answer

Electrical conductivity (EC) and Sodium Adsorption Ratio (SAR)

Answer

pH and dissolved oxygen

Answer

Total dissolved solids and bicarbonate concentration only

Answer

Nitrate concentration and water temperature