Help & Learning Center

How does the Illinois calculator determine my phosphorus needs?

Overview:

The Illinois calculator can be used to help create phosphorus recommendations for your fertility strategies.

Requirements:

Customers must be enrolled in Encirca® Premium Fertility service to use the Illinois calculator.

Answer:

The Illinois calculator utilizes the following equations:

Nutrient

Crop

Build/Maintenance

Phosphorus

Corn

Bray P1:

High Supply Power: If (STP * 2) < 40, P Rec = ((40 - (STP * 2) * 9 / 4) + (0.37 * Yield); if (STP * 2) > = 40 and (STP * 2) <= 60, then P Rec = (0.37 * Yield)

Medium Supply Power: If (STP * 2) < 45, P Rec = ((45 - (STP * 2) * 9 / 4) + (0.37 * Yield); if (STP * 2) > = 45 and (STP * 2) <= 65, then P Rec = (0.37 * Yield)

Low Supply Power: If (STP * 2) < 50, P Rec = ((50 - (STP * 2) * 9 / 4) + (0.37 * Yield); if (STP * 2) > = 50 and (STP * 2) <= 70, then P Rec = (0.37 * Yield)

Mehlich 3-COL: STP = (0.84 * STP as M3-COL) + 1.21

Olsen Bicarbonate: STP = (2.27 * STP as Olsen) - 7.045

Mehlich 3-ICP: STP = (0.778 * STP as M3-ICP) - 6.4667

Phosphorus

Soybeans

Bray P1 or Mehlich 3-COL:

High Supply Power: If (STP * 2) < 40, P Rec = ((40 - (STP * 2) * 9 / 4) + (0.75 * Yield); if (STP * 2) > = 40 and (STP * 2) <= 60, then P Rec = (0.75 * Yield)

Medium Supply Power: If (STP * 2) < 45, P Rec = ((45 - (STP * 2) * 9 / 4) + (0.75 * Yield); if (STP * 2) > = 45 and (STP * 2) <= 65, then P Rec = (0.75 * Yield)

Low Supply Power: If (STP * 2) < 50, P Rec = ((50 - (STP * 2) * 9 / 4) + (0.75 * Yield); if (STP * 2) > = 50 and (STP * 2) <= 70, then P Rec = (0.75 * Yield)