Comparing methods for determination of N uptake in winter wheat

Local and current soil nitrogen (N) mineralisation should guide supplemental N rates. To facilitatethis, methods for rapid assessment of crop N uptake (kg N/ha) were tested in five winter wheat(Triticum aestivum L.) trials in Sweden, around GS39. Four types of measurements were done:leaf sensors, handheld canopy sensors, multispectral drone cameras, and other, manual methods.Several options were found to be simple and accurate enough (mean absolute error for practical use by farmers and advisors. The best results were obtained when leaf and canopymeasurements were combined.