Evaluation of a Reduced Cost Active NDVI Sensor for Crop Nutrient Management
Table 6
Pocket sensor NDVI values based on 95% confidence levels for turf grass, wheat, and maize canopies.
Sensor
Crop
Type estimate
Pred. NDVI
Range NDVI
Pred. NDVI
Range NDVI
Pred. NDVI
Range NDVI
Pred. NDVI
Range NDVI
Pred. NDVI
Range NDVI
Mean NDVI by sensor
0.4
0.5
0.6
0.7
0.8
19
Grass
Average
0.388
0.497
0.605
0.713
0.821
19
Grass
95% extreme
0.372
0.016
0.479
0.018
0.585
0.020
0.691
0.022
0.797
0.023
0.020
20
Grass
Average
0.402
0.505
0.607
0.710
0.812
20
Grass
95% extreme
0.388
0.014
0.489
0.016
0.589
0.018
0.690
0.019
0.791
0.021
0.018
27
Grass
Average
0.401
0.508
0.614
0.721
0.828
27
Grass
95% extreme
0.386
0.015
0.491
0.017
0.596
0.018
0.701
0.020
0.807
0.022
0.018
32
Grass
Average
0.398
0.499
0.599
0.700
0.800
32
Grass
95% extreme
0.382
0.016
0.481
0.018
0.580
0.019
0.679
0.021
0.777
0.023
0.019
37
Grass
Average
0.403
0.507
0.610
0.713
0.816
37
Grass
95% extreme
0.388
0.016
0.489
0.018
0.590
0.019
0.692
0.021
0.793
0.023
0.019
27
Maize
Average
0.403
0.507
0.611
0.716
0.820
27
Maize
95% extreme
0.348
0.054
0.446
0.061
0.544
0.068
0.642
0.074
0.739
0.081
0.068
37
Maize
Average
0.408
0.508
0.607
0.707
0.806
37
Maize
95% extreme
0.378
0.030
0.474
0.034
0.570
0.037
0.666
0.041
0.762
0.044
0.037
20
Wheat
Average
0.418
0.517
0.616
0.716
0.815
20
Wheat
95% extreme
0.369
0.049
0.464
0.053
0.559
0.057
0.654
0.062
0.749
0.066
0.057
32
Wheat
Average
0.403
0.502
0.601
0.700
0.798
32
Wheat
95% extreme
0.346
0.057
0.440
0.062
0.534
0.067
0.628
0.071
0.723
0.076
0.067
Pred. NDVI: predicted NDVI based on pocket sensor reading. Range NDVI: NDVI difference from average predicted value. Type estimate: average: average value based on pocket sensor calibration. 95% extreme: the most extreme value displayed by the pocket sensor with 95% confidence limit.