A New Approach for Nitrogen Status Monitoring in Potato Plants by Combining RGB Images and SPAD Measurements

Precise nitrogen (N) application ensures the best N status of potato plants to improve crop growth and food quality achieve use efficiency. Four fertilization levels (0, 2, 4 6 g pot−1) were used establish a critical dilution curve (CNDC) cultivated in substrates with greenhouse environment. RGB images obtained, red–green fit index (RGFI) was calculated based on linear relationship between R G channels principle excess green (EXG). The substrate can meet nutritional requirements during first 35 days after emergence. In order solve complex sampling problem maintaining sufficient strip for aboveground dry biomass (DM) concentration, reference method detecting proposed. RGFI SPAD values from economically optimum pot−1 treatment derive curve. had high correlations fitted second-order polynomial function an R2 value 0.860 RMSE 2.10. validation results show that concentration constructed by effectively distinguish N-limiting non-N-limiting treatments, CNDCs could be as effective monitoring tool production.