UT Sensors & Controls Lab -- Project Reports


	Field Evaluation of Selective Spraying Systems (Weed Sensors & Weed Maps)

	Low commodity prices are forcing producers to continuously search for new technologies and production practices that will reduce input expenses. One technology that promises cost savings is selective herbicide application equipment. Selective sprayers generally work by using reflected light measurements to determine the difference between bare soil or stubble and growing plants. When used to scan the soil/weed complex between crop rows, selective sprayers can be used to apply herbicides. Significant material savings generally result, since no spray is wasted on bare soil/stubble. In contrast to other precision application techniques that depend on application maps and positioning systems, selective sprayers make application decisions during the operation. Because decisions are made in real time, no application map is required, and no spatial record of material application is generated. Often, a spatial record of material application is needed, especially by researchers evaluating selective sprayer technologies as part of a weed control/management system. UT Sensors and Controls Lab researchers have developed a system capable of recording the information needed to generate maps of selective sprayer herbicide applications. The mapping system, also know as the discrete event recorder (DER), is capable of recording data from a selective sprayer while simultaneously logging positional data generated by an external DGPS receiver. The DER is housed inside a weather-proof enclosure, and can log data for over 80 hours without any attention from the operator. Several performance tests were conducted, and the DER proved suitable for field application. The DER was installed at two locations during 2001 (Texas Agricultural Experiment Station, Lubbock, TX, and North Carolina Agricultural Research Service, Raleigh, NC), and will be used in additional research work in Texas and North Carolina during 2002 and 2003.


	Publications:
		Peters, D.A., P.A. Dotray, J.W. Keeling, T.A. Murphree, and J.B. Wilkerson. 2002. Site specific weed management in roundup ready cotton. In Proceedings of the Southern Weed Science Society, 146. Atlanta, Ga., 28-30 Jan. Peters, D.A., P.A. Dotray, J.W. Keeling, J.B. Wilkerson, and F.H. Moody. 2002. Light-activated hooded sprayer: a two-year evaluation in high plains cotton. In Proceedings of the Beltwide Cotton Conferences, Unpaginated CD-ROM. Atlanta, Ga., 8-12 Jan. Sewell, N.D. 2002. Data acquisition system for evaluating spatial accuracy of selective-type sprayers. M.S. thesis. The University of Tennessee, Knoxville, Tenn.

	Industry Partners and Collaborators:
		Cotton Incorporated North Carolina Agricultural Research Service Texas Agricultural Experiment Station

	For more information about this project, please contact:

		John Wilkerson, Ph.D. The University of Tennessee 2506 E. J. Chapman Drive Knoxville, TN 37996-4531 PHONE: (865) 974-7266 wilkerj@utk.edu