Quick facts
- The canola crop has become an important part of the crop rotations in northern Minnesota.
- Yields have increased as improved management practices are adopted by growers.
- Improved fertilizer management is one major contributor to improved yields.
Nitrogen guidelines
Nitrogen (N) fertilizer guidelines can be based either on the results of the soil NO3--N test or the consideration of expected yield, previous crop, and soil organic matter content. The soil NO3--N test is appropriate for western Minnesota
When the soil NO3--N test is used the N guidelines can be derived from the following equation:
Nitrogen fertilizer formula
Suggested N in lb./acre = (6.5) (EY) - STN(0-24 in.) Npc
Nitrogen formula variables
- EY = expected yield (lb./acre)
- STN = nitrate-nitrogen (NO --N) measured to a depth of 24 in. (lb./acre)
- Npc = amount of N supplied by the previous legume crop (lb./acre). These N credits are summarized in table 6.
Nitrogen guidelines in the first table are for canola in situations when the soil NO3--N test is not used based on expected yield of the crop in pounds per acre.
Nitrogen guidelines
| Crop grown last year | Organic matter level* | 10-15 lb./acre yield | 16-20 lb./acre yield | 21-25 lb./acre yield | 25+ lb./acre yield |
|---|---|---|---|---|---|
| Alfalfa (4+ plants/ft2) | Low | 0 lb. N/acre | 0 lb./ N/acre | 0 lb. N/acre | 0 lb. N/acre |
| Alfalfa (4+ plants/ft2) | Medium/High | 0 | 0 | 0 | 0 |
| Alfalfa (23 plants/ft2) | Low | 0 | 0 | 0 | 0 |
| Alfalfa (23 plants/ft2) | Medium/High | 0 | 0 | 0 | 0 |
| Soybeans or alfalfa (1 or less plants/ft2) | Low | 0 | 10 | 20 | 30 |
| Soybeans or alfalfa (1 or less plants/ft2) | Medium/High | 0 | 0 | 0 | 0 |
| Group 1 Crops | Low | 0 | 0 | 0 | 0 |
| Group 1 Crops | Medium/High | 0 | 0 | 0 | 0 |
| Group 2 Crops | Low | 40 | 50 | 60 | 70 |
| Group 2 Crops | Medium/High | 20 | 30 | 40 | 50 |
- Low = less than 3.0%; medium/high = 3.0% 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
The listed rates are suggested for a broadcast application.
Phosphate fertilizer guidelines (pounds of P2O5 suggested to apply per acre) for canola production are based on either the Bray-P1 or Olsen soil methods test and 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:
- P2O5 rec = [3.60 (0.17) (Bray P, ppm)] (Expected yield)
- P2O5 rec = [3.60 (0.22) (Olsen P, ppm)] (Expected yield)
Phosphate 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 |
|---|---|---|---|---|---|
| 1015 cwt./acre | 40 lb./acre | 25 lb./acre | 15 lb./acre | 0 lb./acre | 0 lb./acre |
| 1620 cwt./acre | 55 | 40 | 25 | 0 | 0 |
| 2125 cwt./acre | 75 | 50 | 30 | 10 | 0 |
| 25+ cwt./acre | 80 | 55 | 35 | 10 | 0 |
Potash fertilizer guidelines (pounds of K2O suggested to apply per acre) for canola production are 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 = [0.0358 (0.023) (Soil Test K, ppm)] (Expected yield)
Potash guidelines
| Expected Yield | 0-40 ppm | 40-80 ppm | 80-120 ppm | 120-160 ppm | 160+ ppm |
|---|---|---|---|---|---|
| 1015 cwt./acre | 60 lb./acre | 40 lb./acre | 25 lb./acre | 0 lb./acre | 0 lb./acre |
| 1620 cwt./acre | 85 | 60 | 35 | 10 | 0 |
| 2125 cwt./acre | 110 | 80 | 45 | 15 | 0 |
| 25+ cwt./acre | 115 | 85 | 50 | 15 | 0 |
Sulfur guidelines
The canola crop is very responsive to sulfur fertilization. When this crop is grown on heavy textured soils, a rate of 10 to 15 pounds of sulfur per acre is suggested. The suggested rate increases to 20 to 30 pounds of sulfur per acre when this crop is grown on sandy soils. Broadcast applications are appropriate for this crop.
Other nutrients
There is no research data to suggest that other nutrients are needed in a fertilizer program for canola production. Therefore, none are recommended.
CAUTION: Do not apply fertilizer in contact with the seed at planting.
Reviewed in 2023