Your objective should be to have a sprayer that is properly maintained and calibrated in order to avoid expensive downtime during the upcoming season. When you’re racing the clock trying to get fertilizer and crop protection chemicals applied in a timely manner, the last thing you need is to see a small, neglected problem become a big problem.
Once you put the batteries back into the sprayer, pull it out of the shop, spread and lower the booms in the down position, and grease the machine from one end to the other, including the chassis, suspension and booms, paying attention to all fold points. Whether the sprayer has been stored over the winter in a heated shop or not, grease has a tendency to fall out or melt away. Proper and thorough greasing of your sprayer is the first important place to start. Next, make a close inspection of the rig — look at the boom for signs of paint missing and developing rust and examine hoses closely for blisters.
Next, fill the spray tank with clean water, turn on the pump and run it through the system for proper rinse-out through the boom. This is a great time to check that the liquid pump is operating to ensure full range of control and hitting the high-pressure marks. This will help clear out any corrosion you might have from materials applied the previous year.
By far, the biggest mistake that farmers make at the beginning of the season has to do with proper calibration. No matter how well calibrated the sprayer was when you first purchased it, it needs to be closely checked and recalibrated at the beginning of each season. Failure to do this can result in serious misapplications. Check all of the nozzles closely — they don’t last forever. Nozzles do wear and, depending on targeted application rates and the materials that are applied, they can wear quickly and result in misapplication.
Proper clean-out of spray tanks, pumps, hoses and the entire system is also becoming increasingly important as farmers and applicators use more tank mixes and herbicide chemistries with different modes of action in an effort to fight herbicide-resistant weeds and improve overall weed management. This is especially important when switching from PGR herbicides to glyphosate.
Here are some simple guidelines designed to ensure your sprayer is in top condition before heading to the field.
General Inspection Tips
A complete preseason inspection of your machine should be performed to make a list of areas that need repair before the season, and possibly a list of potential problem areas to be watched closely during the season. Fixing small problems when they are found to keep them from becoming a problem that could take the machine out of service.
Keep a log of any areas that may need attention during the season. Without a log, these problems may be forgotten and turn into larger problems.
On your checklist should be the following items:
• Check oil and fluids.
• Check tires.
• Check fuel/water separator.
• Follow daily greasing schedule.
• Drain water from air tanks.
• Inspect suspension.
• Clean ladder and platform to cab.
• Check for leaking fluids.
• Check all air filters, including the primary, charcoal and recirculation filters. Replace if needed.
• Clean cab windows.
Liquid Systems Tips
The liquid system of your application rig is where your money is made, so peak performance is essential. Here are the items that should be on your maintenance checklist:
• Disassemble product pump and check for impeller wear and contamination.
• Verify maximum pressure.
• Check for leaky seals.
• Inspect hoses for leaks, brittleness and bulging.
• Check condition of hose clamps.
• Ensure that breakaway boom system functions operate properly.
• Ensure that all boom motions operate properly.
• Check cylinders for leaks and condition of hoses.
• Disassemble and clean strainers.
• Replace damaged mesh.
• Check section shutoffs for on/off speed and proper operation.
Not having your spray system calibrated can cost you through misapplied fields with over- or under-applications, and by having to re-spray.
There is a direct correlation between the number of calibrations and spray accuracy. According to a University of Nebraska study of farmers, nearly 70% who calibrate more than once a year spray within 5 percent of the correct application rate. This contrasts with 95% who miss the mark when only calibrating once a year or less.
There are several areas on a self-propelled sprayer that have to be addressed for proper calibration: speed; flow meter; and nozzles. Proper calibration of the radar or wheel speed sensors is essential.
Calibration of the vehicle speed will ensure accurate application. A target application rate of 24 ounces per acre with a target application speed of 12 mph will result in an actual application rate of 18 ounces per acre when the actual ground speed is 15 mph. For proper speed calibration, use this equation: old calibration number multiplied by a known measurement, divided by what the console shows equals the new calibration number.
The old calibration number is the speed calibration number that is currently entered into the controller. For known measurement, you need to have a known distance to drive. The minimum distance is 400 feet, but the longer the distance, the more accurate the calibration will be. So a distance of one mile is recommended for the most accurate calibration.
Before driving the known measurement, find the area in the controller that counts up the distance driven. Clear that function and drive your marked distance. Use the number shown for distance driven for this portion of the formula: old calibration number multiplied by the actual distance driven divided by what the console shows.
Flow Meter Calibration
Flow meter calibrations should be done on a regular basis to ensure an accurate application. A flow meter that is out of calibration can cause an over- or under-application of product.
For example, at a target application rate of 24 oz./acre and a target application speed of 12 mph, a flow meter reading 10 percent under actual will cause an over application of 2.4 oz./acre. That means that in just 1,000 acres, you would have over applied 75 quarts of product. This is lost profit.
For flow meter calibration, use the following formula: old calibration number, multiplied by what the console shows, divided by a known measurement. This figure is the new meter calibration.
Nozzles may be one of the smallest components on a sprayer, but they are just as important as the engine. Without either one, fields will not get sprayed. Nozzles are important to control the amount (gallons per acre), determine uniformity of application, affect the coverage and influence the drift potential.
Nozzles that are worn by as little as 10% may not give you the coverage and performance you expect. Worn nozzles will affect the amount of chemical applied to an area and change the uniformity of the application, which may lead to poor coverage and having to respray.
It is important to keep track of new and used nozzles — mixing of new and used nozzles will cause an inconsistent spray pattern and application across the spray boom. Use an air compressor to clean nozzle orifices. As a general rule, choose the following droplet types for best performance: “fine” for fungicides and insecticides, “medium” for herbicides and “coarse” for pre-emergence products.
Attention to all of these details will ensure that your sprayer works flawlessly and gives you the best possible return on your equipment investment. Fixing problems when they are small and easy to correct is the best way to ensure your applications are on target and your sprayer will do exactly what it is designed to do.