Agricultural Lime Tons Per Acre Calculator
Calculate ag lime tons per acre from the soil pH gap and the lime's effective neutralizing value, with total tons for the field.
How This Calculation Works
Base lime rate equals the pH gap times about 1.2 tons per acre per pH unit, then divided by the effective neutralizing value as a fraction. A 0.9 pH gap at 70 percent ENV gives about 1.54 tons per acre. Total lime is that rate times acres.
Field Calibration & Rate Reference Chart
| Analysis | Nutrient % | Target lb/ac | Product lb/ac |
|---|---|---|---|
| 46-0-0 Urea | 46 | 100 | 217 |
| 46-0-0 Urea | 46 | 120 | 261 |
| 34-0-0 AN | 34 | 100 | 294 |
| 28-0-0 UAN | 28 | 120 | 429 |
| 18-46-0 DAP | 46 | 60 | 130 |
| 11-52-0 MAP | 52 | 60 | 115 |
| 0-0-60 Potash | 60 | 80 | 133 |
| 10-10-10 | 10 | 60 | 600 |
| 19-19-19 | 19 | 80 | 421 |
| 6-4-0 Milorganite | 6 | 48 | 800 |
Common Questions
How many tons of lime per acre do I need?
It depends on the soil test buffer pH and the lime's effective neutralizing value. A common rule is about 1.2 tons per acre per pH unit of gap, adjusted for ENV. Always follow the soil test recommendation for your soil type.
What is effective neutralizing value?
ENV combines the lime's calcium carbonate equivalent with its fineness to estimate how much will actually react in the soil. A higher ENV means less material is needed. A 70 percent ENV lime requires more tons than a 90 percent ENV lime for the same pH change.
When should I apply agricultural lime?
Apply in the fall so it has time to react before the next crop, and incorporate it into the top 6 to 8 inches where it works best. No-till systems need smaller, more frequent applications. Lime moves slowly through the soil, so surface application takes longer to change subsoil pH.
How often should I lime?
Retest soil every 2 to 4 years and reapply as the pH drops. Sandy soils need lime more often because they buffer less. Heavy clay soils hold pH longer but need higher initial rates.