Spreader Patterns Using ASAE S341.2 Compared to Patterns in Golf-cup Sized Holes in Turfgrass

Abstract

ASAE Standard S341.2 (1993), Procedure for Measuring Distribution Uniformity and Calibrating Broadcast Spreaders, specifies a procedure for conducting pattern tests under controlled situations. The Standard does not specify the surface on which the tests are to be conducted, and thus a paved surface is frequently used for pattern testing. Conducting the tests on a hard surface allows particles to bounce into the collection trays, thus distorting the apparent pattern. A comparison was made between pattern tests conducted according to ASAE S341.2 on smooth concrete and on two species of turfgrass. For the turfgrass tests, the samples were collected in plastic cups set flush with the thatch in round holes cut by a golf cup hole cutter. This procedure eliminated particles bouncing out of the collection devices and allowed bouncing in only to the extent present in actual application to turfgrass. The results showed a major change in both pattern width and apparent delivery rate with large, heavy fertilizer particles. The results verified that a large amount of material bounced into the collection trays in the standard lab tests, thus giving a distorted view of the pattern. With small, light particles, the difference was much less pronounced since less bouncing occurred with those products in the standard laboratory tests.