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Iowa State University

Life Sciences

Matthew J. Darr

Pneumatic

Publication Year

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Rate Response Assessment From Various Granular Vrt Applicators, John P. Fulton, Scott A. Sherer, Stephen F. Higgins, Matthew J. Darr, Timothy S. Stombaugh Jan 2005

Rate Response Assessment From Various Granular Vrt Applicators, John P. Fulton, Scott A. Sherer, Stephen F. Higgins, Matthew J. Darr, Timothy S. Stombaugh

Matthew J. Darr

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, …


Comparison Of Vrt Granular Applicators, John P. Fulton, Scott A. Shearer, Steven F. Higgins, Timothy S. Stombaugh, Matthew J. Darr, Dennis W. Hancock, Edward L. Hutchins Aug 2004

Comparison Of Vrt Granular Applicators, John P. Fulton, Scott A. Shearer, Steven F. Higgins, Timothy S. Stombaugh, Matthew J. Darr, Dennis W. Hancock, Edward L. Hutchins

Matthew J. Darr

Granular applicators equipped with variable-rate technology have gained popularity in recent years due to increased interests in variable-rate application. The purpose of this investigation was to characterize distribution patterns at varying rates and quantify rate transitions from various granular applicators. Both uniform- and variable-rate tests were conducted to assess the accuracy of variable-rate application from four granular applicators (2 spinner spreaders and 2 pneumatic applicators). The patterns results indicated a consistent triangular pattern for spinner spreader B and consistent patterns for pneumatic applicators C and D. However, applicator D produced pattern variations at the center and right side. Simulated overlap …