Timely fertilizer management topics

May 1, 2019 – Issue 5

How much fertilizer does canola need? Nitrogen: Nitrogen uptake is 2 to 3 pounds of available N per bushel of seed yield. What soil reserves and mineralization do not supply must come from fertilizer. Phosphorus: Current recommendations are 1.25 to 1.5 pounds of phosphate per bushel of yield. Sulphur: Canola needs 0.5 to 0.8 pounds of sulphur (S) per bushel of yield, making it a high S-using crop. Potassium: Canola plants need 2.3-2.5 pounds of potassium (K2O) for every bushel of seed yield. Most Prairie soils provide enough K. Micronutrients: Tissue analysis of canola at flowering show sufficiency at these levels: 29 parts per million (ppm) for boron, 19 ppm for iron, 14 for manganese, 14 for zinc, 2.6 for copper and 0.02 for molybdenum. The Canola Council of Canada boron trials found no consistent yield benefit from boron treatment, including in those plots with very high yield results. READ MORE

Why limit seed-placed fertilizer? The safe recommendation for seed-placed fertilizer for canola is this: Apply no more than 20 lb./ac. of phosphate in the seed row. Place all other fertilizer, including extra required phosphate, in a side band or mid-row band where it will not harm germinating seeds. Generally, small-seeded crops such as canola are more sensitive to seed-placed fertilizer, especially nitrogen and potassium. And the risk is higher in dry soil conditions. READ MORE See the Canola Encyclopedia section on this topic. Try the SDSU calculator to estimate seed damage from seed-placed fertilizer.

Quick test for safe rates of seed-placed fertilizer. At what rate does seed-placed fertilizer start to reduce canola stands? A quick test for the safety of seed-placed fertilizer is to turn off the fertilizer feed for about 100 feet, mark the spot, and go back and compare stand establishment in treated and untreated areas. You may want to try this at a few sites in a field: hill tops, side slopes, an easy-to-view area near the road. READ MORE

Trying lime this year to manage clubroot and/or improve fertilizer uptake? Keith Gabert would like to hear from you. Email gabertk@canolacouncil.org.

Canola Watch