EQUIPMENT BASICS
By Dennis Shepard, Ph.D., Syngenta Professional Products
S
pray applications are often a key part of a turfmanagement program. Which products to apply (and when) can play an important role in how well the turf responds to an application.
Over the past several years, sprayer technology has improved. Computerized systems now take the guesswork out of speed and spray-volume considerations. Chemical companies have developed products that are active at lower rates for longer periods and that are safer to the environment, with formulations that are easier to apply. Sprayer and chemical improvements, however, can be negated if the chemicals are not applied to the turf properly. Even though nozzles are a small part of the overall operation, they are the last piece of equipment that sprays must pass through before hitting the turf. Several nozzle types are available from various manufacturers, and choosing the right nozzle for various applications will improve product performance. No single nozzle will work for all applications. Different types of nozzles with various droplet sizes and volume output can be attached to the spray boom.
18
TENNESSEE TURFGRASS
AUGUST/SEPTEMBER 2008
Nozzle basics The spray nozzle you select will determine the amount of product applied to an area, the uniformity and coverage of the target surface, and the amount of potential drift. Information about the spray output and spray angle is usually imprinted on the spray nozzle (Photo 1). The spray angle can range from 65o to 110o, depending on how the nozzle is manufactured. Nozzles can operate at different pressure ranges, but 30 to 60 PSI is the standard for turf applications. As pressure increases, spray droplets will be smaller, spray volume and drift potential will increase, and nozzles may wear sooner. An increase in pressure should be used only to make small increases in volume output. A doubling of pressure will not double the amount of output. In fact, the pressure must be increased 4X to double the output from a nozzle. Nozzles that apply a flat fan pattern are the most common type for turf applications. The flat fan spray nozzle forms a narrow, elliptical, inverted “V� pattern. Spray output is heaviest at the center of the pattern and dissipates toward the outer edge. For most flat fan spray patterns, a minimum 30% overlap between the nozzles is recommended. A decrease in pressure will decrease the overlap, and coverage may decrease.
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