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Management Guidelines for Precision Farming : Nitrogen
Published by the American Society of Agricultural and Biological Engineers, St. Joseph, Michigan www.asabe.org
Citation: Paper number 021018, 2002 ASAE Annual Meeting . @2002
Authors: R J Godwin, G.A.Wood, J.C.Taylor, R. Earl, S. Knight, J. Welsh, B S Blackmore
Keywords: Precision farming, nitrogen, fertilizer, winter wheat, NDVI, yield maps
The results of a 6 year study to develop practical management strategies for spatially
developing nitrogen are reported. The results show that there are significant advantages from
spatially varying nitrogen application rate in “real time” using the crop density of winter wheat in the
spring period. Average economic benefits of £22/ha have been found together with a one third
reduction in the residual nitrogen. From these results a strategy has been developed to aid farmers in
varying the application rate of nitrogen given the crop status at selected growth stages. Yield maps
where shown to be of little value for deciding upon the next seasons nitrogen application; there are
however, valuable indicators for the replenishment of phosphorous and potassium.