# Canola fertilizer recommendations

In recent years, the canola crop has become an important part of the crop rotations in northern Minnesota. Yields have increased as growers adopt improved management practices. Improved fertilizer management is one major contributor to improved yields. Read these nutrient guidelines for improved canola production.

## Nitrogen

We base nitrogen fertilizer guidelines 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 (see Figure 1). With the soil NO3--N test, we use the following equation:

N_{rec} = (6.5) (EY) - STN_{(0-24 in.)} - N_{Pc}

Where:

EY = expected yield (cwt/acre)

STN = nitrate-nitrogen (NO3--N) measured to a depth of 24 in. (lb./acre)

N_{pc} = amount of N supplied by the previous legume crop (lb./acre).

Table 1 summarizes these N credits.

Table 2 lists the fertilizer guidelines for situations where the soil test is not used

## Table 1: Nitrogen credits

Previous crop | First-year nitrogen credit |
---|---|

Soybean | 20 lbs. of N per acre |

Edible beans, field peas | 10 lbs. of N per acre |

Harvest sweetclover | 10 lbs. of N per acre |

Harvested alfalfa*: 4 to 5 plants per square foot | 75 lbs. of N per acre |

Harvested alfalfa*: 2 to 3 plants per square foot | 50 lbs. of N per acre |

Harvested alfalfa*: 1 or fewer plants per square foot | 0 lbs. of N per acre |

Harvested red clover | 35 lbs. of N per acre |

*Add 20 pounds of N per acre to the credits listed if the third or fourth cutting wasn’t harvested.

Table lists 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.

## Table 2: Nitrogen fertilizer guidelines

Crop grown last year | Organic matter level* | Expected yield: 10-15 cwt./acre | Expected yield: 16-20 cwt./acre | Expected yield: 21-25 cwt./acre | Expected yield: 25+ cwt./acre |
---|---|---|---|---|---|

Alfalfa (4+ plants per square foot) | Low | 0 lbs. of N per acre | 0 lbs. of N per acre | 0 lbs. of N per acre | 0 lbs. of N per acre |

Alfalfa (4+ plants per square foot) | Medium and high | 0 lbs. of N per acre | 0 lbs. of N per acre | 0 lbs. of N per acre | 0 lbs. of N per acre |

Alfalfa (2 to 3 plants per square foot) | Low | 0 lbs. of N per acre | 0 lbs. of N per acre | 0 lbs. of N per acre | 0 lbs. of N per acre |

Alfalfa (2 to 3 plants per square foot) | Medium and high | 0 lbs. of N per acre | 0 lbs. of N per acre | 0 lbs. of N per acre | 0 lbs. of N per acre |

Soybeans | Low | 0 lbs. of N per acre | 10 lbs. of N per acre | 20 lbs. of N per acre | 30 lbs. of N per acre |

Alfalfa (1 or fewer plants per square foot) | Medium and high | 0 lbs. of N per acre | 0 lbs. of N per acre | 0 lbs. of N per acre | 0 lbs. of N per acre |

Group 1 crops (see below) | Low | 0 lbs. of N per acre | 0 lbs. of N per acre | 0 lbs. of N per acre | 0 lbs. of N per acre |

Group 1 crops (see below) | Medium and high | 0 lbs. of N per acre | 0 lbs. of N per acre | 0 lbs. of N per acre | 0 lbs. of N per acre |

Group 2 crops (see below) | Low | 40 lbs. of N per acre | 50 lbs. of N per acre | 60 lbs. of N per acre | 70 lbs. of N per acre |

Group 2 crops (see below) | Medium and high | 20 lbs. of N per acre | 30 lbs. of N per acre | 40 lbs. of N per acre | 50 lbs. of N per acre |

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

#### Crops in Group 1:

Alsike clover, birdsfoot trefoil, grass or 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, sugarbeet, sunflower, sweet corn, triticale and wheat.

## Phosphate, potash and other nutrients

Follow these guidelines for broadcast application.

Table 3 summarizes guidelines for using phosphate fertilizer for canola production. For the phosphorus (P) soil test, use one of the following equations if you want a phosphate guideline for a specific expected yield and a specific P soil test:

- Recommended P
_{2}O_{5}= [3.60 - 0.17) (Bray P in ppm)] (Expected yield) - Recommended P
_{2}O_{5}= [3.60 - 0.22) (Olsen P in ppm)] (Expected yield)

## Table 3: Phosphate fertilizer guidelines

Expected yield | 0-5 parts per million (ppm) Bray and 0-3 ppm Olsen | 0-5 parts per million (ppm) Bray and 0-3 ppm Olsen 6-10 ppm Bray and 4-7 ppm Olsen | 11-15 ppm Bray and 8-11 ppm Olsen | 16-20 ppm Bray and 12-15 ppm Olsen | 21+ ppm Bray and 16+ ppm Olsen |
---|---|---|---|---|---|

10-15 hundredweights (cwt) per acre | 40 lbs. per acre | 25 lbs. per acre | 15 lbs. per acre | 0 lbs. per acre | 0 lbs. per acre |

16-20 cwt per acre | 55 lbs. per acre | 40 lbs. per acre | 25 lbs. per acre | 0 lbs. per acre | 0 lbs. per acre |

21-25 cwt per acre | 75 lbs. per acre | 50 lbs. per acre | 30 lbs. per acre | 10 lbs. per acre | 0 lbs. per acre |

25+ cwt per acre | 80 lbs. per acre | 55 lbs. per acre | 35 lbs. per acre | 10 lbs. per acre | 0 lbs. per acre |

Table 4 shows suggestions for potash use for canola production. Use the following equation if you want a potash guideline for a specific soil test and a specific expected yield:

Recommended K_{2}O = [5.4 - (0.034) (Soil Test K in ppm)] (Expected yield)

## Table 4: Potash fertilizer guidelines

Expected yield | 0-40 ppm K soil test | 41-80 ppm K soil test | 81-120 ppm K soil test | 121-160 ppm K soil test | 160+ ppm K soil test |
---|---|---|---|---|---|

10-15 hundredweights (cwt) per acre | 60 lbs. per acre | 40 lbs. per acre | 25 lbs. per acre | 0 lbs. per acre | 0 lbs. per acre |

16-20 cwt per acre | 85 lbs. per acre | 60 lbs. per acre | 35 lbs. per acre | 10 lbs. per acre | 0 lbs. per acre |

21-25 cwt per acre | 110 lbs. per acre | 80 lbs. per acre | 45 lbs. per acre | 15 lbs. per acre | 0 lbs. per acre |

25+ cwt per acre | 115 lbs. per acre | 85 lbs. per acre | 50 lbs. per acre | 15 lbs. per acre | 0 lbs. per acre |

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

We do not recommend application of other nutrients. There is no research data to suggest that canola crops need applied nutrients beyond nitrogen, phosphate, potash and sulfur.

CAUTION!Do not apply fertilizer in contact with the seed at planting.

Reviewed in 2018