Thursday, 5 January 2006 - 3:15 PM

Variable and reduced rate nitrogen application based on multispectral aerial imagery and directed soil sampling

Derek M. Emerine, InTime, Inc, 207 East Carpenter, Cleveland, MS 39732

Increasing natural gas prices and the subsequent increased cost of nitrogen fertilizer have caused a renewed interest in the possibility of variable or reduced rate nitrogen application. Multispectral imagery was acquired during peak flowering in the 2004 growing season by InTime Inc. on about 2300 acres of cotton on a producer's farm and used to determine where directed soil nitrogen samples would be taken in the 2005 growing season. Directed soil samples were taken in 0-6, 6-12, and 12-24 inch intervals in May 2005, and total available nitrogen was calculated. Depending on the soil test results, 30-80 pounds of nitrogen was applied using either reduced or variable rate application. Variable rate prescriptions were made by InTime Inc., and the producer applied the nitrogen fertilizer with a variable rate spin spreader. As-applied data was collected and significant nitrogen fertilizer savings were observed by the producer. Three multispectral images were obtained by InTime Inc. and, used to make variable rate plant growth regulator, insecticide, and defoliant applications. Determinations will be made on the overall effectiveness of variable or reduced rate nitrogen applications as it relates to yield, PGR costs, insect pressure, and defoliation costs.

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See more of The Beltwide Cotton Conferences, January 3-6 2006