Peas are a major crop grown primarily for processing in Minnesota. The state currently ranks second in the U.S. for pea production with approximately 53,400 acres of peas harvested annually.
Lime needs
Managing pH can be important for legume crops that form symbiotic relationships with rhizobium bacteria that fix nitrogen for the plant. Lime is suggested for peas when the water pH of the soil is less than 6.0. The buffer index is used to determine how much limestone is required to raise the pH of the soil to 6.0.
Nitrogen guidelines
Peas grown for processing purposes are primarily grown in the southern part of Minnesota in areas where a pre-plant soil nitrate test is not suggested for use.
Peas are a legume crop where nitrogen is supplied to the plant through a symbiotic relationship between rhizobium bacteria and the plant roots. Inoculation is suggested if the site has not had a history of pea production. Supplemental nitrogen should not be required in most cases.
Nitrogen fertilizer needs are summarized in the table below and are based on the previous crop grown, soil organic matter concentration in the top six inches, and expected crop yield. A single application of nitrogen prior to planting is sufficient if conditions exist where a response to N is more likely.
Nitrogen guidelines for processing peas
| Crop grown last year | Organic matter level* | <1000 lbs/acre | 1000-1999 lbs/acre | 2000-3999 lbs/acre | >4000 lbs/acre |
|---|---|---|---|---|---|
| Alfalfa (4+ plants/ft2) | Low | 0 lbs N/acre | 0 lbs N/acre | 0 lbs N/acre | 0 lbs N/acre |
| Alfalfa (4+ plants/ft2) | Medium/High | 0 | 0 | 0 | 0 |
| Soybeans or Field Peas (1 or less plants/ft2) | Low | 0 | 0 | 10 | 20 |
| Soybeans or Field Peas (1 or less plants/ft2) | Medium/High | 0 | 0 | 0 | 0 |
| Group 1 Crops | Low | 0 | 0 | 0 | 10 |
| Group 1 Crops | Medium/High | 0 | 0 | 0 | 0 |
| Group 2 Crops | Low | 0 | 10 | 20 | 40 |
| Group 2 Crops | Medium/High | 0 | 0 | 10 | 20 |
*low = less than 3.1%; medium and high = 3.1% or more. Crops in Group 1: Alsike clover, birdsfoot trefoil, grass/legume hay, grass legume pasture, fallow, red clover. Crops in Group 2: Barley, buckwheat, canola, corn, grass hay, grass pasture, oat, potato, rye, sorghum-sudan, sugar beet, sunflower, sweet corn, triticale, wheat.
Phosphate and potash guidelines
When deficient, phosphorus and potassium can limit the pea yield in Minnesota.
Guidelines for broadcast applications of phosphorus and potassium are based on the soil test level for a six-inch soil sample and the expected yield of the crop. Specific guidelines for phosphorus are based on two soil test methods. The Bray-P1 test is most accurate for situations where soil pH is 7.4 or less. If soil pH is 7.5 or greater then the Olsen P test should be utilized to determine fertilizer requirements.
Phosphate fertilizer guidelines
| Expected yield Bray-P1 Expected yield Olsen |
0-5 ppm 0-3 ppm |
6-10 ppm 4-7 ppm |
11-15 ppm 8-11 ppm |
16-20 ppm 12-15 ppm |
21+ ppm 16+ ppm |
|---|---|---|---|---|---|
| 0-999 lbs/acre | 25 lbs/acre | 15 lbs/acre | 0 lbs/acre | 0 lbs/acre | 0 lbs/acre |
| 1000-1999 lbs/acre | 50 | 25 | 15 | 0 | 0 |
| 2000-3999 lbs/acre | 75 | 50 | 25 | 15 | 0 |
| 4000 or more lbs/acre | 100 | 75 | 50 | 25 | 0 |
The application rate in the phosphate table is pounds per acre based on the soil methods test reported in parts per million (ppm). Use one of the following equations if a phosphate guideline for a specific soil test and a specific expected yield is desired:
- P2O5rec = [0.034 - (0.0017) (Bray P, ppm)] (Expected yield)
- P2O5rec = [0.033 - (0.0021) (Olsen P, ppm)] (Expected yield)
Potash fertilizer guidelines
| Expected yield | 0-40 ppm | 41-80 ppm | 81-120 ppm | 121-160 ppm | 160+ ppm |
|---|---|---|---|---|---|
| 0-999 lbs/acre | 25 lbs/acre | 15 lbs/acre | 0 lbs/acre | 0 lbs/acre | 0 lbs/acre |
| 1000-1999 lbs/acre | 50 | 25 | 15 | 0 | 0 |
| 2000-3999 lbs/acre | 75 | 50 | 25 | 15 | 0 |
| 4000 or more lbs/acre | 100 | 75 | 50 | 25 | 0 |
Pounds of potash suggested to apply per acre for processing peas production is based on the ammonium acetate potassium test reported in parts per million (ppm). Use the following equation if a potash guideline for a specific soil test and a specific expected yield is desired:
- K2O rec = [0.034 - (0.0002) (Soil Test K, ppm)] (Expected yield)
Other nutrients
There has been no research demonstrating the need for the application of other secondary macronutrient fertilizers such as calcium, magnesium or sulfur for pea production. The application of micronutrients such as boron, copper, iron, manganese, and zinc is not likely to increase pea yield in Minnesota.
Reviewed in 2022