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37. Calibrate Manure Application Equipment

calibrating a field

Manufacturers estimate how much manure a given spreader applies, but the actual rate will vary, even between the same models of equipment. Therefore, to get the most accurate idea of the rate at which your equipment applies manure, calibrate it. Calibrating your manure application equipment takes less than an hour, but it's one of the best ways to avoid overapplication of fertilizer.

There are a variety of ways to determine your equipment's application rate. Your choice depends on the type of manure—liquid or solid—and the type of spreader. If, by calibrating, you find out that your spreader is applying manure at a rate that is too low or too high, change your travel speed. By increasing the travel speed of your spreader, you reduce the application rate, and vice versa.

PTO Driven, Beater type spreader If you have a PTO-driven, beater-type spreader, keep the engine speed constant and change the application rate by: changing the spreader delivery rate setting; or, changing the tractor gear ratio to alter the spreader's ground travel speed.
Application rate Equation To estimate how much a new travel speed will change the application rate, multiply the spreader's application rate (determined during calibration) by the old travel speed. Divide that number by the new travel speed. The result is the new application rate. Whenever you change your travel speed, be sure to recalibrate the equipment.

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