“…These methods are precise but expensive, destructive, time-consuming and require technical knowledge in sampling which is lacking among farmers. Some manual tools that have aroused interest for in-season N status assessment and crop yield prediction are Crop Circle ACS-470 sensor, Green-Seeker sensor, SPAD chlorophyll meter, CM-100 Chlorophyll meter, Yara N-Sensor, Crop Circle ACS-430 multiplex sensor, hand-held Field Spectro-Radiometer sensor (Analytical Spectral Devices, Inc., Boulder, CO, USA) and CropScan (Muñoz-Huerta et al, 2013;Cilia et al, 2014;Maresma et al, 2016Maresma et al, , 2018Chlingaryan et al, 2018;García-Martínez et al, 2020). Green-Seeker sensor and CM-100 Chlorophyll meter are mostly used as tools to assess in-season N status and predict crop yield in various crops due to their ease of use and portable aspect.…”