On-the-Go Cotton Nitrogen Management
In 2006, we found that early square sensor readings from Cropscan, Cropcircle and Greenseeker instruments were poorly correlated with optimum N rates (too early to use). However mid square and early flower sensor readings appear to have promise for producing accurate N rate prediction on the go. Shown below are the best fit equations for calibrations with x= reading in high N cotton plot and y= optimum N rate in pounds N per acre.
Cropscan near-infrared reflectance (810 nm) relative to high N plots
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y = -66.2.32x + 683.43
|
R2=0.94 |
Cropscan green/infrared (560/810 nm) relative to high N plots |
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y = 557.81 x - 547.68 |
R2=0.86 |
Greenseeker red/near-infrared relative to high N plots |
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y =124.94 x - 99.275 |
R2=0.70 |
Cropcircle yellow/near-infrared relative to high N plots |
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y = 180.74x - 149.58 |
R2=0.65 |
