American Society of Agricultural and Biological Engineers



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Pulse-Width Modulation Metering System for Ammonia Fertilizer

Published by the American Society of Agricultural and Biological Engineers, St. Joseph, Michigan www.asabe.org

Citation:  Paper number  011126,  2001 ASAE Annual Meeting. (doi: 10.13031/2013.4194) @2001
Authors:   Mark D. Schrock, Darrell L. Oard, Randal K. Taylor, Jeff J. Grimm, John D. Anderson, Troy C. Kolb
Keywords:   ammonia, anhydrous ammonia, pulse-width modulation, nitrogen fertilizer, site-specific fertilization.

Coated controlled-release fertilizer granules can be damaged when applied by fertilizer spreaders. Physical damage to the coated granules can change the release rate of the nitrogen since the damaged coating will allow water to pass through the coating and dissolve the nitrogen. Six controlled-release nitrogen fertilizers and a mixed fertilizer containing controlled-release nitrogen granules were applied with six spreaders and samples of the applied products were tested for coating damage. There were highly significant differences in the amount of damage caused by different spreaders. Nominal release rate had a significant effect on amount of damage, with the longer release rates (i.e. thicker coatings) having less damage. Even the highest damage levels to the nitrogen products were under 10%, thus observable differences in crop response are unlikely.

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