CFA Application Equipment and Calibration 3 — Questions and Answers
Question 1: A dry fertilizer applicator needs to apply 150 lbs per acre of a blended product. If the calibration shows the spreader delivers 120 lbs/acre at the current setting, how should the rate be adjusted?
- Increase the gate opening or agitation speed (Correct answer)
- Decrease travel speed and widen effective spread width
- Increase travel speed to cover more ground
- Switch to a liquid fertilizer system
Correct answer: Increase the gate opening or agitation speed
Increasing the gate opening or metering mechanism increases flow rate to achieve the higher target application rate.
Question 2: What is 'skipping' in the context of spreader calibration, and what causes it?
- The spreader bouncing over rough terrain reducing accuracy
- Alternating over- and under-application strips caused by incorrect pass spacing (Correct answer)
- Nozzle clogging causing intermittent output
- Electronic control system malfunctions
Correct answer: Alternating over- and under-application strips caused by incorrect pass spacing
Skipping refers to alternating bands of high and low application caused by swath widths that do not match the spreader's effective pattern width.
Question 3: Which factor does NOT directly affect the output rate of a centrifugal pump on a liquid fertilizer applicator?
- Engine or PTO speed
- System back pressure
- Color of the solution tank (Correct answer)
- Impeller wear
Correct answer: Color of the solution tank
Tank color is irrelevant to pump output; speed, back pressure, and impeller condition all directly affect centrifugal pump performance.
Question 4: What is the purpose of a 'catch test' or 'jug test' when calibrating a sprayer?
- To measure the concentration of active ingredient in the spray solution
- To verify actual nozzle output matches the expected flow rate (Correct answer)
- To check for leaks in the boom plumbing
- To determine the optimal travel speed for the application
Correct answer: To verify actual nozzle output matches the expected flow rate
A catch test collects output from individual nozzles over a timed period to verify they are delivering the correct flow rate.
Question 5: When applying fertilizer with a boom sprayer, what is the recommended practice when a nozzle becomes clogged mid-application?
- Continue at reduced speed to compensate for missing coverage
- Stop, clean or replace the nozzle, and retreat the missed area (Correct answer)
- Increase system pressure to clear the clog automatically
- Skip the affected area and note it in the application record
Correct answer: Stop, clean or replace the nozzle, and retreat the missed area
A clogged nozzle causes under-application and must be addressed immediately; the missed area must be retreated to ensure proper coverage.
Question 6: For a drop spreader calibration, you weigh the material in the hopper before and after making a test pass. The hopper lost 1.2 lbs over 100 feet with a 24-inch effective width. What is the application rate in lbs per 1,000 sq ft?
- 4.0 lbs
- 5.0 lbs (Correct answer)
- 6.0 lbs
- 8.0 lbs
Correct answer: 5.0 lbs
Area = (100 ft x 2 ft) / 1,000 = 0.2 thousand sq ft; rate = 1.2 lbs / 0.2 = 5.0 lbs per 1,000 sq ft.
Question 7: What does a 'CV' (coefficient of variation) value measure in spreader calibration pattern testing?
- The ratio of actual to target application rate
- The statistical variation in distribution uniformity across the spread width (Correct answer)
- The corrosion resistance of the spreader materials
- The travel speed variation during the calibration run
Correct answer: The statistical variation in distribution uniformity across the spread width
CV measures the relative standard deviation of material distribution, with lower values indicating more uniform application across the spread pattern.
CFA Application Equipment and Calibration 3
A dry fertilizer applicator needs to apply 150 lbs per acre of a blended product.
If the calibration shows the spreader delivers 120 lbs/acre at the current setting, how should the rate be adjusted?