The Iowa calculator can be used to help create potassium recommendations.
The Iowa calculator utilizes the following equations:
Nutrient
Crop
Build/Maintenance
Potassium
Corn
If STK <= 160 then K Rec = (138.5 - (0.825 * STK)) / (1 - (0.00532 * STK); if STK >= 161 and <= 200, then K Rec = (0.22 * Yield)
Soybeans
If STK <= 160 then K Rec = (127.9 - (0.699 * STK)) / (1 - (0.00476 * STK); if STK >= 161 and <= 200 then K Rec = (1.20 * Yield)
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