Dias Paiao, Gabriel2017-04-112017-04-112017-01https://hdl.handle.net/11299/185565University of Minnesota M.S. thesis. January 2017. Major: Land and Atmospheric Science. Advisor: Fabián Fernández. 1 computer file (PDF); vii, 78 pages.We evaluated the utility of different canopy sensing tools alone or adjusted with soil nitrogen (N) content to estimate corn grain yield and N requirements at various corn development stages. Canopy sensing measurements with SPAD, GreenSeeker NDVI (GS-NDVI), RapidSCAN NDVI and NDRE (RS-NDVI and RS-NDRE) were obtained at V4, V8, V12 and R1 development stages, and soil NO3--N concentration was measured at V4 stage. RS-NDRE had the best predictive power of grain yield and N requirements. Canopy sensing at V4 growth stage had the lowest utility to help improve corn N management. At later development stages, sensor’s performance was superior, but there is less flexibility to apply N. Applying N from V4 to V8 provided the best potential for sidedress application timings. Soil NO3--N measured at V4 stage from 0-30 cm depth showed potential by itself or in combination with early-season sensor measurements to improve corn fertilizer N.engrain yield predictionnitrogen deficiency determinationsensor-based nutrient managementsoil nitrogen contentsplit applicationThesis or Dissertation