Pattern Assessment of a Spinner Disc Variable-Rate Fertilizer Applicator

Previous work by Fulton et al. (2000) showed the development of a program for generating an “As Applied” map to assess uniform and variable-rate application of potash. The “As Applied” map was created using an “As Applied” file generated during field operation in conjunction with different application patterns determined by Fulton et al. (1999). While modifications are required to improve the program, a rapid method for determining distribution patterns from granular applicators is desired to help limit the test area, keep the material being tested confined to a smaller area, and have the ability to test several spreaders within a days time at different application rates. Therefore, the focus of this investigation is to determine whether static testing of spinner spreaders equipped with variable-rate technology can be performed rather than the dynamic testing outlined in ASAE standard S341.2 or the procedure used by Fulton et al. (1999). Both static and dynamic tests were conducted at application rates of 2241 kg/ha, 4481 kg/ha, and 6722 kg/ha. The distribution patterns at these different rates were determined and then normalized to generate an effective distribution application pattern The authors are solely responsible for the content of this technical presentation. The technical presentation does not necessarily reflect the official position of the American Society of Agricultural Engineers (ASAE), and its printing and distribution does not constitute an endorsement of views which may be expressed. Technical presentations are not subject to the formal peer review process by ASAE editorial committees; therefore, they are not to be presented as refereed publications. Citation of this work should state that it is from an ASAE meeting paper. EXAMPLE: Author's Last Name, Initials. 2001. Title of Presentation. ASAE Meeting Paper No. 01-1116. St. Joseph, Mich.: ASAE. For information about securing permission to reprint or reproduce a technical presentation, please contact ASAE at [email protected] or 616-429-0300 (2950 Niles Road, St. Joseph, MI 49085-9659 USA). using the progressive method outlined in S341.2. To compare the static dynamic testing methods, correlation coefficients of 0.39, 0.58, and 0.33 were calculated for the 2241 kg/ha, 4481 kg/ha, and 6722 kg/ha tests, respectively. The low correlation coefficients along with the variability in the distribution patterns concluded that static testing is unable to replicate the dynamic testing and should not be used to assess distribution patterns. Finally, the variation in the effective distribution patterns (CV’s from 20% to 28%), nonuniform flow of lime onto the spinners, and lime missing the spinners at the high application rate indicated that adjustments and possible modifications are required to produce a more uniform spread pattern.