How does the Tri-State (Indiana, Ohio, Michigan) calculator determine my phosphorus needs?
Overview:
The Tri-State calculator can be used to help create phosphorus recommendations for your fertility strategies.
Answer:
The Tri-State calculator utilizes the following equations:
|
Nutrient |
Crop |
Build/Maintenance |
|
Phosphorus |
Corn |
Bray P1 or Mehlich 3-COL: If STP < = 15 then P Rec = (15 - STP) * 5 + (Yield * 0.37) If STP > 15 and STP < 30 then P Rec = (Yield * 0.37) If STP >= 30 then P Rec = (Yield * 0.37) - ((Yield * 0.37) * (STP - 30)) / 10 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: If STP < = 15 then P Rec = (15 - STP) * 5 + (Yield * 0.80) If STP > 15 and STP < 30 then P Rec = (Yield * 0.80) If STP >= 30 then P Rec = (Yield * 0.80) - ((Yield * 0.80) * (STP - 30)) / 10 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 |
