Table 1. Lime recommendations for mineral soils when the soil pH is less than 6.0. The rates suggested should raise the pH to 6.5.
| SMP Buffer | Area I | Area II | ||
|---|---|---|---|---|
| Index | ENP | Ag Lime* | ENP | Ag Lime* |
| lb./acre | ton/acre | lb./acre | ton/acre | |
| 6.8 | 3000 | 3.0 | 2000 | 2.0 |
| 6.7 | 3500 | 3.5 | 2000 | 2.0 |
| 6.6 | 4000 | 4.0 | 2000 | 2.0 |
| 6.5 | 4500 | 4.5 | 2000 | 2.0 |
| 6.4 | 5000 | 5.0 | 2500 | 2.5 |
| 6.3 | 5500 | 5.5 | 2500 | 2.5 |
| 6.2 | 6000 | 6.0 | 3000 | 3.0 |
| 6.1 | 6500 | 6.5 | 3000 | 3.0 |
| 6.0 | 7000 | 7.0 | 3500 | 3.5 |
| 5.9 | 7500 | 7.5 | 3500 | 3.5 |
| 5.8 | 8000 | 8.0 | 4000 | 4.0 |
| 5.7 | 8500 | 8.5 | 4000 | 4.0 |
| 5.6 | 9000 | 9.0 | 4500 | 4.5 |
* These are approximate recommendations based on the average ENP value of ag lime. An ENP of 1,000 lb. per ton is an average value for ag lime (crushed limestone) in Minnesota.
Table 2. Lime recommendations for mineral soils when the SMP BUFFER TEST IS NOT USED (soil pH is 6.0 or higher). The rates suggested should raise the pH to 6.5.
| Soil-Water | Area I | Area II | ||
|---|---|---|---|---|
| pH | ENP | Ag Lime* | ENP | Ag Lime* |
| lb./acre | ton/acre | lb./acre | ton/acre | |
| 6.5 | 0 | 0 | 0 | 0 |
| 6.4 | 2000 | 2.0 | 0 | 0 |
| 6.3 | 2000 | 2.0 | 0 | 0 |
| 6.2 | 3000 | 3.0 | 0 | 0 |
| 6.1 | 3000 | 3.0 | 0 | 5 |
| 6.0 | 3000 | 3.0 | 2000 | 2.0 |
* These are approximate recommendations based on the average ENP value of ag lime. An ENP of 1,000 lb. per ton is an average value for ag lime (crushed limestone) in Minnesota.
Table 3. Phosphate suggestions for alfalfa production in Minnesota.*
| Phosphorus (P) Soil Test (ppm) | ||||||
|---|---|---|---|---|---|---|
| Yield Goal | Bray: | 0-5 | 6-10 | 11-15 | 16-20 | 21+ |
| Olsen: | 0-3 | 4-7 | 8-11 | 12-15 | 16+ | |
| bu./acre | - - - - - - - - - - - - lb. P2O5/acre to apply - - - - - - - - - - - - | |||||
| 3 or less | 40 | 35 | 20 | 5 | 0 | |
| 4 | 65 | 45 | 25 | 10 | 0 | |
| 5 | 80 | 55 | 30 | 15 | 0 | |
| 6 | 95 | 65 | 40 | 15 | 0 | |
| 7 | 110 | 80 | 45 | 20 | 0 | |
| more than | 125 | 90 | 55 | 25 | 0 | |
* Use the following equation to calculate phosphate fertilizer recommendations for specific yield goals and specific soil test values for P:
No phosphate fertilizer is recommended if the soil test for P is higher than 25 ppm (Bray) or 20 ppm (Olsen).
Back to Phosphate and Potash Management
Table 4. Potash suggestions for alfalfa production in Minnesota.
| Potassium (K) Soil Test (ppm) | ||||||
|---|---|---|---|---|---|---|
| Yield Goal | 0-40 | 41-80 | 81-120 | 121-160 | 161+ | |
| bu./acre | - - - - - - - - - - - - lb. K2O to Apply* (lb./acre) - - - - - - - - - - - - | |||||
| 3 or less | 145 | 100 | 55 | 10 | 0 | |
| 4 | 190 | 130 | 70 | 10 | 0 | |
| 5 | 240 | 165 | 90 | 15 | 0 | |
| 6 | 290 | 195 | 105 | 15 | 0 | |
| 7 | 335 | 230 | 125 | 20 | 0 | |
| more than 7 | 380 | 265 | 145 | 20 | 0 | |
* Use the following equation to calculate potash fertilizer recommendations for specific yield goals and specific soil test values for K:
Back to Phosphate and Potash Management
Table 5. Sulfur suggestions for alfalfa production on sandy soils in Minnesota.
| Soil Test for S | Sulfur Suggestions |
|---|---|
| ppm S | sulfur to apply (lb./acre) |
| 0-6 | 25 (annual) |
| 7-12 | 25 (trial) |
| more than 12 | 0 |
In Minnesota, the soil test for S is only reliable for sandy soils. This soil test has no value for medium and fine textured soils.
Table 6. Boron recommendations for alfalfa production in Minnesota.
| Boron Soil Test | Relative Level | Boron To Apply |
|---|---|---|
| ppm | lb./acre | |
| less than 1.0 | low | 2-4 |
| 1.1 - 5.0 | adequate | 0 |
| more than 5.0 | 0 |