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Article
Rate Response Assessment from Various Granular VRT Applicators
Transactions of the ASAE
  • John P. Fulton, Auburn University
  • Scott A. Shearer, University of Kentucky
  • Stephen F. Higgins, University of Kentucky
  • Matthew J. Darr, The Ohio State University
  • Timothy S. Stombaugh, University of Kentucky
Abstract

Variable-rate technology (VRT) adds complexity to application equipment, thereby confounding the assessment of applicator performance. The intent of this investigation was to assess the rate response of various VRT granular applicators: two spinner spreaders (A and B), and two pneumatic applicators (C and D). Variable-rate (VR) tests were conducted to quantify the rate response characteristics (delay and transition times) for the applicators. A sigmoidal function was used to model the rate response for five of the six tests. Applicator A exhibited a linear response during decreasing rate changes. Results indicated that only applicator B demonstrated consistent delay and transition times, enabling the use of a single “look-ahead” time for rate response time correction. Contouring of prescription maps increased the transition times for applicator D by enlarging the adjustment area between management zones. Rate changes were quicker for the two newer VR control systems, signifying advancement in hydraulic control valve technology. This research illustrates the need for standard testing protocols for VRT systems to help guide VRT software developers, equipment manufacturers, and end users.

Document Type
Article
Publication Date
11-1-2005
Notes/Citation Information

Published in Transactions of the ASAE, v. 48, issue 6, p. 2095-2103.

© 2005 American Society of Agricultural Engineers

The copyright holder has granted the permission for posting the article here.

Digital Object Identifier (DOI)
https://doi.org/10.13031/2013.20086
Funding Information

Funding for this project was provided through a special CSREES-USDA Grant titled, “Precision Agriculture: Development and Assessment of Integrated Practices for Kentucky Producers.”

Related Content
The investigation reported in this article (05-05-038) is in connection with a project of the Kentucky Agricultural Experiment Station and is published with the approval of the Director.
Citation Information
John P. Fulton, Scott A. Shearer, Stephen F. Higgins, Matthew J. Darr, et al.. "Rate Response Assessment from Various Granular VRT Applicators" Transactions of the ASAE Vol. 48 Iss. 6 (2005) p. 2095 - 2103
Available at: http://works.bepress.com/matthew_darr/67/