Table 3. Results of the paired t-test between the 75:25 split validation RMSE of the fresh and removed cotton leaf and fresh and intact cotton leaf macronutrient and micronutrient models that were constructed from the NIR spectra captured using the PhoneLab™.
The results include the p-value of the paired t-test. The complete accuracy parameters of the dried and ground and fresh and removed calibrations are available in Table S5.
| Fresh and removed | Fresh and intact | p-Value | Preferred sample preparation | |
|---|---|---|---|---|
| Macronutrient | Validation RMSE (%) | Validation RMSE (%) | ||
| Total nitrogen | 0.26 | 0.28 | 0.035 | – |
| Phosphorus | 0.11 | 0.11 | 0.509 | – |
| Potassium | 0.44 | 0.41 | 0.028 | – |
| Calcium | 0.63 | 0.56 | 0.005 | Fresh and intact |
| Magnesium | 0.11 | 0.12 | 0.089 | – |
| Sulfur | 0.38 | 0.38 | 0.953 | – |
| Petiole total N | 0.34 | 0.31 | 0.015 | – |
| Nitrate-N+ | 832.85 | 772.09 | 0.116 | – |
| Micronutrient | Validation RMSE (mg/kg) | Validation RMSE (mg/kg) | ||
| Iron | 85.65 | 68.85 | 0.013 | – |
| Manganese | 60.62 | 52.94 | <0.001 | Fresh and intact |
| Copper | 1.15 | 1.26 | 0.001 | Fresh and removed |
| Zinc | 9.76 | 9.06 | 0.186 | – |
| Molybdenum | 176.38 | 166.22 | 0.200 | – |
| Boron | 20.08 | 18.95 | 0.119 | – |
| Chloride | 2,800.00 | 2,700.00 | 0.868 | – |
| Sodium | 281.83 | 251.16 | 0.002 | Fresh and intact |
Note:
+
RMSE (mg/kg)