CIT Soil Science and Plant Water Requirements

Question 1

Which soil type has the highest water-holding capacity?

Accepted Answer

Clay soil

Answer

Sandy soil

Answer

Loamy sand

Answer

Gravelly soil

Question 2

Field capacity is defined as the soil moisture level that remains after:

Accepted Answer

Excess water has drained away by gravity

Answer

Plants have absorbed all usable water

Answer

The soil is fully saturated by heavy rain

Answer

The permanent wilting point is reached

Question 3

The permanent wilting point is the soil moisture level at which:

Accepted Answer

Plants can no longer extract water and wilt permanently

Answer

Sandy soils can no longer hold water

Answer

Irrigation must begin immediately to prevent stress

Answer

Field capacity is re-established

Question 4

Which of the following best describes evapotranspiration (ET)?

Accepted Answer

The combined loss of water through soil evaporation and plant transpiration

Answer

The rate at which water drains below the root zone

Answer

The total rainfall received by a landscape in a season

Answer

The efficiency rating of an irrigation system

Question 5

Plant Available Water (PAW) is correctly calculated as:

Accepted Answer

Field capacity minus permanent wilting point

Answer

Saturation minus field capacity

Answer

Total precipitation minus surface runoff

Answer

Irrigation depth minus evaporation losses

Question 6

Sandy soils typically have infiltration rates closest to which range?

Accepted Answer

1.5 to 3.0 inches per hour

Answer

0.1 to 0.2 inches per hour

Answer

0.3 to 0.5 inches per hour

Answer

0.5 to 1.0 inches per hour

Question 7

Which soil texture is most recommended for turfgrass because it balances drainage and moisture retention?

Accepted Answer

Sandy loam

Answer

Pure clay

Answer

Pure sand

Answer

Gravel