Table 2. Hollow heart incidence from different areas of the fields irrigated with VRI systems. Numbers followed by different letters are significantly different at p<0.05. Hollow heart incidence Area of the field Nozzle control VRI Dry Average Wet 8% A 13% A 15% A Speed control VRI 3% b 5% ab 13% a Table 3. Irrigation efficiency of the speed control VRI system in different areas of the field. Numbers followed by different letters mean significant difference at p<0.05. Area of the field Dry Average Wet Irrigation efficiency (lb of tubers/inch of irrigation water) 9 AB 8 B 12 A incidence of hollow heart in tubers from the wettest areas of both fields, and the difference was significant under the speed control system (Table 2). During storage under 48°F, we observed higher incidence of rotting in tubers from the wettest areas of both fields (Figure 3). It is thought that the tubers grown in saturated soils had enlarged lenticels on the surface, which created perfect entry points for pathogens in field and during storage. In addition, we calculated irrigation efficiency (IE) of the speed control VRI system (numbers of the nozzle control VRI were not available), and it showed that there was a significant improvement of IE in the wettest area compared to the average area of the field. IE in the driest area was slightly higher than the average (Table 3). For nitrogen status, using NDVI to predict petiole nitrate-N generated the best R2 results for both potato types, compared to whole leaf total N and whole vine total N. For total yield prediction, DT and RF were better than SVM, and the results for 2019 were better than 2018. So far we have found that: 1) decision tree and random forest 36 Spudman.comhttp://www.Spudman.com