Table 2.
Results of linear regression prediction of N concentration in tomato leaves from SPAD (chlorophyll meter readings) and SAP (measurements of N-NO3 concentration in petiole) analysis. Efficiency parameters reported: correlation coefficient (r), Standard Error of Prediction (SEP), Root Mean Square Error (RMSE), Squared bias (SB), nonunity (NU) and lack of correlation (LC).
| Parameter | SPAD | SAP |
|---|---|---|
| MODEL (85%) | ||
| n° samples | 100 | 100 |
| r (measured vs. predicted) | 0.5383 | 0.5638 |
| SEP | 0.6260 | 0.6135 |
| RMSE | 0.3918 | 0.3763 |
| TEST (15%) | ||
| n° samples | 17 | 17 |
| r (measured vs. predicted) | 0.5589 | 0.5594 |
| SEP | 0.7169 | 0.7537 |
| RMSE | 0.6420 | 0.6978 |
| SB | 0.12 | 0.12 |
| NU | 0.0003 | 0.0517 |
| LC | 0.4834 | 0.483 |