Estimation of Dry Matter and N Nutrient Status of Choy Sum by Analyzing Canopy Images and Plant Height Information

The estimation accuracy of plant dry matter by spectra- or remote sensing-based methods tends to decline when canopy coverage approaches closure; this is known as the saturation problem. This study aimed enhance and subsequently use critical nitrogen dilution curve (CNDC) diagnose N in Choy Sum analyzing combined information imaging height. A three-year experiment with different levels (0, 25, 50, 100, 150, 200 kg∙ha−1) was conducted on Sum. Variables (CC) height were used build model. results showed that yields N0 N25 significantly lower than those high-N treatments (N50, N100, N150, N200) for all three years. variables CC × Height had a significant linear relationship matter, R2 values above 0.87. good performance Height-based model implied problem prediction well-addressed. By contrast, between best fitted an exponential function. CNDC models built based could satisfactorily differentiate groups deficiency abundance treatments, implying their feasibility diagnosing status. application rates 50–100 kgN/ha are recommended optimal yield production region.