Environmental Engineering Reference
In-Depth Information
Appendix
Application of Fertilizers and Other Dry
Materials with a Spreader
Greg Wiecko, UOG Station/CNAS, Mangilao, Guam 96923, USA
telephone (671) 735-2132, fax (671) [734-7657], e-mail gwiecko@uog9.
uog.edu
Dry fertilizers can be applied with either a drop (gravity) spreader or a
rotary (centrifugal) spreader. A drop-type spreader has the advantage of
applying fertilizer in a quite accurate pattern, but it requires that each edge
of successive 'passes' (swaths of area covered by the spreader) meet
exactly; if they do not, 'skips' (unfertilized areas between passes) and
overlaps will be noticeable. The rotary spreader generally has a wider
patternof distribution than adrop spreader andcan therefore cover a larger
area in the same amount of time. Its application pattern also gradually
diminishes with distance from the machine, reducing the probability of
skips. This spreader is harder to calibrate andapplication is less precise, but
it is sufficiently accurate for most home or lower-maintenance areas.
One method that increases uniformity of application is to divide the
material to be applied (see below for calculation of the proper amount)
into two equal portions applied separately. Use a spreader calibration
that will deliver one-half of the desired amount of material, and apply
one-half of the material over the entire area. Then turn the spreader
direction 90
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from that of the initial application and apply the remainder
