1. Calibration Stamp

2. Blue Dye, 30 ml L-1 20 80 60
100 40
lb N/ac

3. Calibration Stamp Applied in December
Winter Wheat
Calibration Stamp Applied in December
Visual Interpretation in February or March

4. Topdress N rate prescribed by choosing the lowest N rate where no visual differences are observed between that rate and the highest rate

5. Results
Field-specific topdress N rate prescribed by choosing the lowest N rate where no visual differences were observed between it and the highest rate.
N Rate NDVI N Rate NDVI N Rate NDVI

6. Calibration Strips
0 lb/ac
40 lb/ac
120 lb/ac
80 lb/ac

7. ATV Mounted Calibration Strip Applicator

8. ATV Mounted Calibration Strip Applicator
OSU has established demonstration calibration strips in 16 counties in Oklahoma

9. “Nitrogen Use Efficiency”
Google
“Nitrogen Use Efficiency”

10. OSU Calibration Strip Applicator Design Instructions