Application Equipment and Calibration Flashcards

An applicator calibrates a broadcast spreader with an effective swath width of 12 feet. They drive a 100-foot test course and collect 3.0 lbs of fertilizer. What is the application rate in pounds per acre?

Answer: 121 lbs/acre

The calibrated area is the swath width (12 ft) multiplied by the distance (100 ft), which equals 1,200 sq ft. To find the rate per acre, divide the amount collected (3.0 lbs) by the area covered (1,200 sq ft) and then multiply by the number of square feet in an acre (43,560). The calculation is: (3.0 lbs / 1,200 sq ft) * 43,560 sq ft/acre = 108.9 lbs/acre, which is rounded to 109 lbs/acre.

Which of the following is a primary advantage of using a drop spreader over a rotary (broadcast) spreader for granular fertilizer application?

Answer: More precise placement of material with less chance of off-target application.

Drop spreaders release material directly underneath the hopper between the wheels, offering highly precise placement. This makes them ideal for areas next to sidewalks, driveways, or sensitive landscape beds where preventing off-target application is critical. Rotary spreaders are faster for large areas but are less precise at the edges.

When using a ground-driven broadcast (rotary) spreader, which of the following operator actions would most likely DECREASE the fertilizer application rate (lbs/acre)?

Answer: Increasing the walking or driving speed.

For a ground-driven spreader, the rotational speed of the impeller is tied to the ground speed. However, as ground speed increases, the amount of time the spreader spends over any given area decreases. This means less material is applied per unit of area, thus decreasing the application rate (lbs/acre). Decreasing speed or increasing overlap would increase the rate.

An applicator notices distinct, parallel green and yellow streaks in a turf area after fertilizing with a rotary spreader. What is the most likely cause of this application error?

Answer: Incorrect overlap between spreader passes.

The "streaking" or "striping" effect is a classic sign of improper overlap. The dark green streaks are where passes overlapped (receiving a double rate), and the yellow streaks are areas between passes that received little or no fertilizer. Driving too fast or setting the gate too high would affect the entire area more uniformly, not typically in distinct streaks.

To minimize spray drift when making a liquid fertilizer application on a slightly windy day, which type of nozzle would be the best choice?

Answer: A low-pressure, large-droplet air induction nozzle.

Air induction (or venturi) nozzles are specifically designed for drift control. They create large, air-filled droplets that are heavier and less susceptible to being carried off-target by wind. Fine-mist nozzles and operating nozzles at high pressures create very small, drift-prone droplets.

An applicator is calibrating a boom sprayer and measures the nozzle flow rate in gallons per minute (GPM), the travel speed in miles per hour (MPH), and the nozzle spacing in inches (W). Which formula correctly calculates the application rate in Gallons Per Acre (GPA)?

Answer: GPA = (GPM * 5940) / (MPH * W)

The standard formula for calibrating a sprayer in Gallons Per Acre (GPA) is GPA = (GPM × 5940) ÷ (MPH × W), where GPM is the nozzle output, 5940 is a conversion constant, MPH is the ground speed, and W is the nozzle spacing in inches. This formula correctly integrates all variables to determine the final application volume over a given area.