Monday, 7 November 2005
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Wheat Response to Variable Rate N Strategies Using Active Ndvi Sensors.

Jonah T. Johnson, Gregory J. Schwab, Lloyd W. Murdock, and Eugenia Pena-Yewtukhiw. University of Kentucky, Department of Plant and Soil Sciences, 845 Red Mile Road Apt. 301, Lexington, KY 40504

Precision agriculture allows producers to vary inputs according to the spatial yield potential of a crop, which could decrease input cost, increase economic return, and reduce environmental impacts associated with N loss. In the past, variable rate application (VRA) effectiveness has been impeded by applicators that are much larger than crop variability. Today, with the aid of new, innovative equipment, fertilizer can be variably applied on a 0.56 m2 area using field scale equipment controlled by active, real-time Normalized Difference Vegetative Index (NDVI) sensors. An experiment was conducted in Kentucky using a commercially available spraying system (GreenSeeker) to assess variable rate N fertilization strategies on wheat (Triticum aestivum L.) yield across a variable landscape. Test plots for the first year had four replications of four treatments. The N rate was varied spatially for two treatments while the other two treatments received uniform applications. In the second year of the study, six additional treatments were added. There was a general trend for higher yields when using VRN compared to uniform applications. It also appears that maximum yields can be obtained with less N when using this system.

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