Fertilizer planning: Seed-placed rates, logistics, in-crop applications

March 1, 2019 – Issue 3

What fertilizer to put in the seed row? Canola needs sulphur, but there is no clear benefit to putting sulphur fertilizer in the seed row. It will likely cause more harm than good because the seed row should already have up to 20 lb./ac. of phosphate, which does show an early-season benefit. Adding ammonium sulphate fertilizer to the seed row increases the risk of seedling death, driven by toxicity from the nitrogen component. Ammonium sulphate is better put in a band outside the seed row. Why limit seed-placed fertilizer?

How much fertilizer does canola need? Canola is a high-sulphur-using crop, and usually benefits from the some sulphur fertilizer even when composite soil test results show the field has reasonable sulphur levels. That’s because sulphur can be highly variable across a field. Unless you have grid sample results and are set up for variable rate sulphur applications, a low blanket rate can be beneficial. In fields short of sulphur, use soil test recommended rates. Canola is also a high-nitrogen-using crop. In high producing areas of a field, farmers may get be able to increase profits with higher nitrogen rates – especially with good moisture. Potassium may be deficient in some fields, but this would depend on soil test results. Most fields across the Prairies are sufficient in potassium, especially for canola. Details: How much fertilizer does canola need?

What are your logistical challenges to following the 4Rs? 4R Nutrient Stewardship is a framework encouraging growers to use the four ‘Rights’: Right Source at the Right Rate, Right Time, Right Place. The principle is to use nutrient sources that the crop needs and can take up, apply them at a rate to match crop use, apply them at the right time of the season to minimize losses and be available when the crop needs it, and put them in the right place to minimize loss and maximize crop access to the nutrient. Applying all of canola’s fertilizer needs at the time of seeding in a one-pass system might check a lot of 4R boxes, but it can present a logistics challenge at seeding. Banding into the soil ahead of seeding is a ‘Right Time’ alternative but it can damage the seedbed, which is why some farms fall band nitrogen. Another option is in-field top dress. If that is something you might consider, this would be a good time to think about the equipment required. More about the 4Rs.

Canola Watch