Nitrogen management is critical for sugarbeet (Beta vulgaris L.) because N inversely influences root yield and recoverable white sucrose per tonne (RWST). From 2015 to 2017 in Ontario the use of optical sensors (SPAD, Greenseeker) was evaluated as a method to guide N application and harvest date (late-September, late-October) selection by predicting root yield RWST and partial profit margins. In a commercial field, fertilizer N rate (4, 5) and cultivar (8, 12) were tested in a split block design experiment with three replications and two harvest dates. In all years, few cultivars (β€2) had a root yield response to applied N, which was attributed to high inherent soil fertility and limited our evaluation of optical sensors to adjust in-season N applications. The optimal N rate to maximize RWST and profits was 0 to 45 kg N haThe accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author