If no soil tests are available, Fertility Management calculates Nutrient Needs using Nutrient Removal Rates. Nutrient Removal Rates were developed by each state as an estimate of the amount of phosphorus or potassium removed at grain harvest.
If no soil test results are available, Fertility Management uses the previous crop year’s yield data to generate Nutrient Needs to replace removed nutrients from the soil. If no soil tests or previous yield exists in Fertility Management, yield goals from the current crop year are used with Nutrient Removal Rates based on the selected calculator.
The table shows crop removal rates for phosphorus (P2O5) and potassium (K2O) by calculator and crop.
A yield of 50 bushels per acre of soybeans was harvested in an Illinois soybean field. How many pounds of P2O5 and K2O were estimated to be removed?
60 bu/acre * 0.75 lbs/bu P2O5 = 45 lbs/ac P2O5
60 bu/acre * 1.17 lbs/bu K2O = 70.2 lbs/ac K2O