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OPERATORS of drop-type fertilizer spreaders often assume that the spreader meters in a volumetric manner; i.e. delivery rate per revolution is constant and independent of speed. At least one major reference work on the subject states that this assumption is true. A test was run at the Louisiana Agricultural Experiment Station using two popular drop-type spreaders and two materials under controlled laboratory conditions. The results clearly show that drop spreader application rate does vary with speed, but is not completely gravimetric; i.e. the flow rate is not constant with respect to time. The application rate of a typical drop-type spreader is variable and falls between volumetric and gravimetric.