The Davey Tree Expert Company provides residential and commercial tree service and landscape service throughout North America. Read our Flipbooks for helpful tips and information on proper tree and lawn care.
Issue link: https://daveytree.uberflip.com/i/795219
63 Calibration and understanding of equipment flow rates promote proper application rates, herbicide efficiency, and herbicide effectiveness. The following tables are intended to help calibrate equipment for broadcast applications with boomless nozzles. Proper application requires the operator to determine the flow rate or gallons per minute (GPM) of the spray nozzles. Using a spray truck equipped with an application control panel is recommended. With a control panel set up, the application rate or gallons per acre (GPA) is controlled, and the flow rate or GPM will fluctuate based on the ground speed. With this system, the operator must set the nozzle spray width and verify or set the application rate based on gallons per acre. The recommended GPA of the herbicide solution can be found on the herbicide product label. When using a spray truck without a control panel, the GPM is not controlled by instruments and must be controlled by the speed of the driver. In this case, additional calibration will be required. The nozzle manufacturer's specifications provide a calibration table to determine GPM based on nozzle spray width, pounds per square inch (PSI), GPA, and ground speed. This calibration table should be used to verify all settings. Once the spray truck's settings are known, the applicator should check the nozzle spray pattern to verify the nozzle is spraying the intended width. The applicator should put water in the tank and practice on dry pavement (pictured below left). The applicator should measure the pattern sprayed on the ground to verify nozzles are functioning properly. When applied correctly, the water pattern will dry evenly. Always make these adjustments with water before going out on the right-of-way to make applications with herbicide. The first table below can be used to determine how much time it will take to spray 1 acre based on chosen nozzle spray width and ground speed. Use the second table to determine the distance in linear feet and lane miles to spray 1 acre based on nozzle spray width. CALIBRATION GUIDANCE FOR BROADCAST HERBICIDE APPLICATIONS 4 5 6 7 8 9 10 20:38 16:30 13:45 11:47 10:19 9:10 8:15 12:23 9:54 8:15 7:04 6:11 5:30 4:57 6:11 4:57 4:07 3:32 3:06 2:45 2:29 4:08 3:18 2:45 2:21 2:04 1:50 1:39 3:06 2:29 2:04 1:46 1:33 1:23 1:14 6 10 20 30 40 7,260 4,356 2,178 1,452 1,089 1.4 0.8 0.4 0.3 0.2 TIME REQUIRED TO SPRAY ONE ACRE BASED ON GROUND SPEED AND NOZZLE SPRAY WIDTH LANE-MILE DISTANCE OF ONE ACRE BASED ON NOZZLE SPRAY WIDTH GROUND SPEED (MPH) 6-FOOT NOZZLE SPRAY WIDTH (MINUTES: SECONDS) 10-FOOT NOZZLE SPRAY WIDTH (MINUTES: SECONDS) 20-FOOT NOZZLE SPRAY WIDTH (MINUTES: SECONDS) 30-FOOT NOZZLE SPRAY WIDTH (MINUTES: SECONDS) 40-FOOT NOZZLE SPRAY WIDTH (MINUTES: SECONDS) NOZZLE SPRAY WIDTH (FEET) LINEAR FEET PER 1 ACRE (FEET) LANE MILES PER 1 ACRE (MILE)