BRAE 340 Midterm 3

What are the four major factors that determine the numerical value of the crop coefficient Kc?

Crop, stage of growth, soil surface wetness, and plant moisture stress

The correct relationship between the ET for a reference crop and the evapotranspiration for some other particular crop is:

ETc = Kc * ETo

Which of the following pairs would be LEAST likely to generally improve irrigation efficiency?

Achieve advance ratios greater than 0.5 and achieve opportunity time ratios less than 0.5.

T/F: The USBR operates the CIMIS program to provide ETo and Kc information in Calfornia.

False

T/F: A lysimeter is a container filled with soil and a growing crop which is weighed to determine water use.

True

T/F: The MAD would be the same for cracking and non-cracking soils.

False

Which of these is NOT a DISADVANTAGE of low on-farm irrigation efficiency?

a. Higher energy costs due to excess pumping

b. Increased fertilizer costs due to excess leaching

c. Water quality degradation

d. Drainage problems or increased drainage costs

e. Decreased time between irrigations

e. Decreased time between irrigations

Air dry soil surface, root zone moisture high enough to cause no stress: How does Kc relate to Kcb?

Kc is equal to Kcb

Air dry soil surface, root zone moisture low enough to cause some stress: How does Kc relate to Kcb?

Kc is lower than Kcb

Wet soil surface, root zone moisture high enough to cause no stress: How does Kc relate to Kcb?

Kc is higher than Kcb

Wet soil surface, root zone moisture low enough to cause some stress: How does Kc relate to Kcb?

Impossible to tell

T/F: Torpedoes are ineffective when used to compact the bottoms and sides of furrows.

False

T/F: The RPM of the motor remains the same as the flow rate changes.

True

T/F: The efficiency of an electric motor is typically fairly consistent around 90%.

True

When starting a pump from the electric panel you should do which of the following?

Use your non dominate hand to press the start button, shield your eyes and face, stand to the side of the panel, look away from the panel

If you know the motor efficiency and the power running through an electric meter, what can you calculate?

BHP

What is the key information that is needed when selecting a pump?

The flow rate required by the system, the TDH required by the system

T/F: California, like most Western states, uses an alfalfa reference for determining ETo.

False

T/F: A lysimeter is a container filled with soil and a growing crop which is weighed to determine salinity.

False

Which of these is NOT a DISADVANTAGE of low on-farm irrigation efficiency?

a. Increased cost for systems due to excess capacity required

b. Water quality degradation

c. Reduced area irrigable with a fixed volume of water

d. Drainage problems or increased drainage costs

e. Increased district support due to reuse of non-bneficial water by others

Increased district support due to reuse of non-bneficial water by others

T/F: Under surface irrigation, soil infiltration rates are not constant over the season.

True

T/F: As the TDH of a pump increases the flow rate decreases.

True

T/F: The efficiency of an electric motor changes depending on the flow rate of the pump.

False

Two identical pumps in series will ______.

double the pressure

T/F: The DWR operates the CIMIS program to provide ETo and Kc information in Calfornia.

True

T/F: There are over 150 active weather stations throughout the CIMIS network in California.

True

Which of these is NOT an ADVANTAGE of improving low on-farm irrigation efficiency?

A. Reduced fertilizer costs due to reduced leaching

B. Elimination of water quality degradation due to application and reuse by others

C. Minimized capacity-related system costs

D. Increased water supply

E. Reduced drainage problems or drainage costs

E. Reduced drainage problems or drainage costs

T/F: Sloping furrow systems are best treated as variable amount, fixed frequency systems.

False

T/F: As we increase the flow rate from a booster pump the TDH decreases.

True

The easiest way to determine the pumping plant efficiency is to determine the ______ and the _______.

IHP, WHP

Pump efficiency _______.

tends to be the highest near the middle of the pump curve

Which of the following pairs would be MOST likely to generally improve irrigation efficiency?

A. Achieve opportunity time ratios less than 0.5 and collect and reuse runoff.

B. Eliminate runoff from sloping furrows and collect and reuse runoff.

C. Use long furrow lengths and and minimize evaporation & spray losses.

D. Proper irrigation time/amount and achieve good DU.

E. Achieve opportunity time ratios less than 0.5 and achieve good DU

D. Proper irrigation time/amount and achieve good DU.

T/F: 7 or 19 hr/day are typical, convenient irrigation set times for hand move sprinkler systems.

False

Which of these is NOT a DISADVANTAGE of low on-farm irrigation efficiency?

a. Water quality degradation

b. Increased cost for systems due to excess capacity required

c. Drainage problems or increased drainage costs

d. Reduced effectiveness of non-water-related farming operations

e. Higher energy costs due to excess pumping

D. Reduced effectiveness of non-water-related farming operations

T/F: The best efficiency point is where the efficiency curve peaks.

True

Two identical pumps in parallel will ______.

double the flow rate