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Extension > Agriculture > Nutrient Management > Nutrient/Lime Guidelines > Fertilizer Recommendations for Agronomic Crops in Minnesota > Canola

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Fertilizer Recommendations for Agronomic Crops in Minnesota

Canola

Daniel E. Kaiser, Extension Soil Scientist; John A. Lamb, Extension Soil Scientist; and Roger Eliason, Director, University of Minnesota Soil Testing Laboratory

Revised 2011

subsoil map

Figure 1. The fall soil nitrate test should be used for nitrogen recommendations in the counties that are shaded.

In recent years, 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. The guidelines for improved canola production are described in the sections that follow.

Nitrogen

Nitrogen fertilizer guidelines can be based either on the results of the soil NO3--N test or the consideration of the combination of expected yield, previous crop, and soil organic matter content. The soil NO3--N test is appropriate for western Minnesota (see Figure 1). When the soil NO3--N test is used, the N guidelines can be derived from the following equation:

Nrec = (6.5) (EY) - STN(0-24 in. - NPc

Where:

EY = expected yield (cwt/acre)
STN = nitrate-nitrogen (NO3--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 1.

The fertilizer guidelines for situations where the soil test is not used are listed in Table 2.

Crops in Group 1:

Alsike clover, birdsfoot trefoil, grass/legume hay, grass legume pasture, fallow, and 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, and wheat.

Table 1. Nitrogen credits for various legume crops that might precede barley in a crop rotation. Use these credits for the "Npc" factor in situations where the soil nitrate test is used.

  Previous Crop 1st Year Nitrogen Credit
  lb. N/acre
  Soybean 20
  Edible  beans, field peas 10
  Harvest sweetclover 10
  Harvested alfalfa*  
    4 to 5 plants/ft2 75
    2 to 3 plants/ft2 50
    1 or fewer plants/ft2 0
  Harvested red clover 35

* Add 20 lb. N/acre to the credits listed if the 3rd or 4th cutting was not harvested.

Table 2. Nitrogen guidelines for canola in situations when the soil NO3--N test is not used.

  Expected Yield (bu./acre)
  Crop Grown Last Year Organic Matter Level* 10-15 16-20 21-25 25 +
  Alfalfa (4+ plants/ft2) Low
Med and high

0
0

0
0
0
0
0
0
  Alfalfa (2 to 3 plants/ft2) Low
Med and high
0
0
0
0
0
0
0
0
  Soybeans
  Alfalfa (1 or less plants/ft2)
Low
Med and high
0
0
10
0
20
0
30
0
  Group 1 Crops Low
Med and high
0
0
0
0
0
0
0
0
  Group 2 Crops Low
Med and high
40
20
50
30
60
40
70
50

*Low = less than 3.0%; medium and high = 3.0% or more.

Phosphate and Potash

The guidelines for the use of phosphate fertilizer are summarized in Table 3. The suggestions for potash use are in Table 4. The listed rates are suggested for a broadcast application.

Table 3. Phosphate fertilizer guidelines for canola production.

  Phosphorus (P) Soil Test, ppm*
Expected
Yield
Bray: 0-5 6-10 11-15 16-20 21+
Olsen: 0-3 4-7 8-11 12-15 16+
cwt/acre P2O5 to apply (lb./acre) —
10-15   40 25 15 0 0
16-20   55 40 25 0 0
21-25   75 50 30 10 0
25 +   80 55 35 10 0

* Use one of the following equations if a phosphate guideline for a specific expected yield and a specific P soil test is desired.

P2O5 rec = [3.60 –(0.17) (Bray P, ppm)] (Expected Yield)
P2O5 rec = [3.60 –0.22) (Olsen P, ppm)] (Expected Yield)

Table 4. Potash fertilizer quideline for canola production.

Expected
Yield
Potassium (K) Soil Test, ppm*
0-5 6-10 11-15 16-20 21+
cwt/acre K2O to apply (lb./acre) —
10-15 60 40 25 0 0
16-20 85 60 35 10 0
21-25 110 80 45 15 0
25 + 115 85 50 15 0

* Use the following equation if a potash guideline for a specific soil test and a specific expected yield is desired.

K2O rec = [5.4 – (0.034) (Soil Test K, ppm)] (Expected Yield)

Sulfur

The canola crop is very responsive to sulfur fertilization. When this crop is grown on heavy textured soils, a rate of 10 to 15 lb. of sulfur per acre is suggested. The suggested rate increases to 20 to 30 lb. 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.

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