Canola Nitrogen Rate Trial
Research Question: Are nitrogen (N) rates being used on canola across Manitoba sufficient for optimizing yield and nitrogen efficiency?
Treatments
- Reduced N Rate (75%)
- Standard N Rate (100%) – Farm Normal for Field
- High N Rate (125%)
Trial Setup: Randomized complete block, each treatment was one equipment width x field length, with four replicates per location (12 strips per location)
Data Collection: Plant Counts, Tissue N (bolting), Yield, Protein, Oil Content
Click here to see full protocol.
Trial Results to Date:
Summary of 2022 – 2023 Trial Results
Click the Trial ID in the table below to view the full site report.
| Trial ID (year) | RM | Standard N Rate (100%) | Reduced N Rate (75%) | High N Rate (125%) | CV | |
| N Applied (soil residual N) | Yield | Change in Yield from Standard Rate | ||||
| lbs. N/ac | bu/ac | bu/ac | bu/ac | % | ||
| NR_01 (2022) | Swan Valley West | 113 (76) | 47.1 | -0.4 | +1.6 | 1.8 |
| NR_02 (2022) | Macdonald | 122 (55) | 52.0 | +2.3 | +3.9* | 4.1 |
| NR_03 (2022) | Lorne | 138 (60) | 35.4 | +0.9 | +0.1 | 5.5 |
| NR_04 (2022) | Morris | 120 (53) | 58.6 | -4.2* | +0.4 | 4.5 |
| NR_05 (2022) | Two Borders | 118 (79) | 42.0 | -3.3 | +0.9 | 11.9 |
| NR_06 (2023) | Minitonas-Bowsman | 113 (18) | 55.5 | -5.3* | -0.5 | 5.2 |
| NR_08 (2023) | North Norfolk | 135 (25) | 58.0 | -2.5 | +4.2 | 9.2 |
| NR_09 (2023) | Brokenhead | 137 (30) | 61.7 | -0.9 | +3.0 | 4.2 |
| NR_10 (2023) | Two Borders | 130 (50) | 51.4 | +2.3 | +3.3 | 7.6 |
| NR_11 (2023) | De Salaberry | 158 (127) | 22.8 | -1.3 | -0.1 | 5.5 |
| COMBINED | 129 (57) | 48.4 | -1.3 | +1.6* | 24 | |
Grain Yield
- Average grain yield across all trial locations when the farm normal rate of N fertilizer was applied was 48 bu/ac, ranging from 23 – 62 bu/ac.
- Overall, there was a significant 1.6 bu/ac increase in yield when an additional 25% N fertilizer was applied to the farm standard N rate.
- Two of 10 locations had a significant yield reduction of -4.2 and -5.3 bu/ac when N was reduced by 25%.
- One of 10 locations had a significant yield increase of 3.9 bu/ac when N fertilizer was increased by 25%.
Nitrogen Fertilizer Efficiency
- The current N fertilization recommendation for canola in Manitoba is to provide canola with 2.5 to 3.5 lbs. N (soil + fertilizer) per bushel of yield targeted (Canola Council of Canada and Manitoba Agriculture). Example: for a target yield of 50 bu/ac recommended N would be from 125 to 175 lbs. N/ac (soil + fertilizer).
- N provided to the crop per bushel at farm standard N rate ranged from 2.4 to 5.6 in this trial.
- As the amount of fertilizer supplied to the crop increases the efficiency of N was reduced → more N used per bushel of yield.
Economic considerations will vary farm-to-farm depending on buying price of N fertilizer, canola price and standard N rates.
In Summary
- All results presented are preliminary as this trial will continue in 2024 and 2025 field seasons.
- Farms that saw a decrease in yield with reduced N rates achieved high grain yield (>55bu/ac) with modest N fertilization (2.4 and 2.9 lbs. N/bu yield).
- The significant combined increase in grain yield of 1.6 bu/ac for could be sufficient to cover the added cost of 32 lbs. N/ac ($0.76 lbs. N and $16 canola).
Funded in part by the Governments of Canada and Manitoba under the Sustainable Canadian Agricultural Partnership, a federal-provincial-territorial initiative.
