Table 4.
Explanation of variation in dependent variable (VDV) from partial least squares regression modeling for dry biomass and canopy height by sensor estimation models and model equations for height (combination ultrasonic and laser model) and biomass (two sensor model: laser and ultrasonic combination, and three sensor model: laser, ultrasonic and NDVI combination). † MIX-Mixture of alfalfa and bermudagrass; ‡ ALL-All monoculture and mixed species from the alfalfa and bermudagrass experiment.
| Canopy Height | Plate Meter | 120 MHz Ultrasonic | Laser | |
|---|---|---|---|---|
|
| ||||
| DM | VDV | VDV | VDV | VDV |
|
| ||||
| Alfalfa | 68.5% | 18% | 55% | 64% |
| Bermudagrass | 69% | 23% | 75% | 78% |
| Wheat | 72% | 74% | ||
| MIX † | 67.8% | 19% | 73% | 73% |
|
| ||||
| 3 sensor model | 3 sensor equation | 2 sensor model | 2 sensor equation | |
|
| ||||
| Alfalfa | 65.7% | (46.22 × Las) + 47.83(Son × NDVI) | 65.5% | (46.9 × Las) + (43.13 × Son) |
| Bermudagrass | 80.5% | (65.3 × Las) + 58.3(Son × NDVI) | 81% | (65.7 × Las) + (49 × Son) |
| Wheat | 75% | (118 × Las) + 108(Son × NDVI) | 74% | 231 × Las |
| MIX | 78.9% | 70.5(Las × NDVI) + 63.7(Son × NDVI) | 78.5% | (61.3 × Las) +(53.9 × Son) |
|
| ||||
| Plate meter | 120 MHz ultrasonic | Laser | ||
|
| ||||
| Canopy height | VDV | VDV | VDV | |
|
| ||||
| Alfalfa | 1.2% | 57% | 69% | |
| Bermudagrass | 6.1% | 67% | 77% | |
| MIX | 5.6% | 54% | 61% | |
| ALL ‡ | 6.1% | 55% | 64% | |
|
| ||||
| 2 sensor model | 2 sensor equation | |||
|
| ||||
| Alfalfa | 70% | (0.46 × Las) + (0.42 × Son) | ||
| Bermudagrass | 77% | 1.02 × Las | ||
| MIX | 64% | 0.017(Las × Son) | ||
| ALL | 65% | (0.74 × Las) + (0.2 × Son) | ||