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Chapter 4.6

The ideal spacing between spreader passes is equal to the effective spreader width. Using the graph, identify the horizontal distances to the left and right of the center where the application rate fell to 50 percent of the maximum observed during the test. The distance between these two points on either side of center is the effective spreader width. Spacing the passes one effective spreader width from the last should provide an ideal application overlap that will result in a relatively uniform application.

Verifying Application Rate and Spreader Pass Spacing

Once again, spread manure at the same speed and setting over the test area where sheets or pans are laid out, only this time make three passes. Spread the first pass directly over the center of the collection area. Make the remaining two passes, one effective spreader width to the left and right of the center of the first pass.

Weigh the manure collected and calculate the application rate for each of the pans, sheets or sheet sections across the width of the test area. If the spacing between spreader passes is correct the application rate across the width of the test area should be relatively consistent. If application rates appear to be heavier in between spreader passes, this suggests that the spreader passes should be made further apart. Conversely, if application rates are noticeably lighter in between, spreader passes should be moved closer together.

Record the average application rate across the width of the test area, the speed and setting (if applicable) used during the calibration. If applying solid manure the density of the manure should be recorded as well. This information can be used to quickly recalculate applications speeds and setting if manure with a different density is to be applied with the same machine and is discussed in the following section.

Source: B.C. Ministry of Agriculture, Forestry and Lands, 2005

Figure 4.6.3 Sample Application Uniformity Curve Generated from the Results of a Uniformity Test