The Use of Global Positioning Systems and Aerial Photography to Determine Tiller Development in Wheat

Ronnie Heiniger, Randy Weisz, Michael Flowers

Abstract:	There is increasing evidence that early scouting of wheat fields to determine tiller numbers can be useful in deciding when spring nitrogen (N) should be applied. Unfortunately, good tiller counts require a large amount of time and effort. Also, tiller counts can be extremely variable within a field making it difficult to get a good average value without taking many samples. The solution to this problem is to take advantage of remote sensing in the form of aerial photography. Aerial photography used with the aid of information collected with a portable differential global positioning system (DGPS) could help determine tiller counts for the whole field and to examine the variability in tiller counts within a field. This approach would have several benefits for wheat farmers. First, it would reduce the time and effort required to scout tiller numbers and, therefore, increase the use of tiller scouting in managing wheat production. Second, it could help determine the variability in wheat stands within a field leading to improvements in planting accuracy. Finally, aerial photography could be used to direct site-specific applications of N which would reduce the amount of N used while increasing the yield potential of the wheat crop. To determine if aerial photography and precise field scouting using DGPS could be used to count tillers, four experiments were established on farm fields in North Carolina. Tiller counts were taken at GS 25 (Zadok’s scale), and locations were marked using a DGPS receiver. At the same time aerial photographs were taken using infrared film. Comparisons of tiller counts to amount of infrared band reflection found in the infrared photographs at GS 25 showed a strong correlation. This research indicates that tiller counts could be determined using aerial photography.
Published in:	Proceedings of the 12th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GPS 1999) September 14 - 17, 1999 Nashville, TN
Pages:	2033 - 2040
Cite this article:	Heiniger, Ronnie, Weisz, Randy, Flowers, Michael, "The Use of Global Positioning Systems and Aerial Photography to Determine Tiller Development in Wheat," Proceedings of the 12th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GPS 1999), Nashville, TN, September 1999, pp. 2033-2040.
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