As is typical in many parts of Canada, if you don’t like the weather, wait five minutes. March 2021 in Alberta was a perfect example of this popular adage, with mid to high teen temperatures in the south and single digit temps in the central to northern regions of the province. There was sun, wind, rain, snow, and farmers wondering what it will all lead to this seeding season.
Despite the weather, the seed must be sown. It’s always important to remember that just before the seed goes into the ground, we view the crop as having its highest level of yield potential at that moment. Indeed, every action taken between seeding and harvest is an attempt to preserve and enhance crop yield. Because of this, we need to focus on the things we can control at the time of seeding to ensure rapid and even emergence and get the crop off to the best start possible.
A few of the main actions to get seed off to the best start possible are looking at soil temperature, seeding depth, seeding rates and seed row fertilizer.
Soil temperature — We don’t want to seed too early, but we don’t want to wait too long to seed either. Cereals and pulses are the most tolerant of cool soil, especially compared to oilseeds, so think about planting them first. Using a soil temperature gauge, make sure the soil temperature is between four to five degrees Celsius. We use that mark because once the soil hits that range, we’re about seven to 10 days away from crop emergence after planting. If seeding earlier than that, we’re delaying crop emergence, and if we seed after that, when the soil warms up even more, time to emergence can be reduced even further. With smaller-seed canola or oilseeds, wait for soil temperatures above five degrees Celsius, or even closer to seven or eight degrees. Typically, warmer soil is going to equal rapider emergence and that is important because seed treatments often have a limited time of protection. We usually think of seed treatments lasting maybe 10 days to two weeks, so the quicker we can get the crop out of the ground, the more it is protected.
Seeding depth — Smaller sized seeds have fewer reserves, so oilseeds need to be seeded a little shallower. They don’t have the carbohydrate energy to be able to push through deeper soil — they rely on getting their seedlings out of the ground and photosynthesizing rapidly. Target half an inch deep for canola, under ideal conditions. Even if the soil is dry, don’t push canola seed down hoping to seed into moisture.
Larger sized seeds like cereals and pulses have more energy reserves so they can push through the soil — thus, we can seed them a little deeper and they can still emerge and have vigour when they get to the surface. Aim for one to two inches deep for cereals and pulses.
When it comes to seeding depth, one of the main issues seen in fields is uneven or unlevel drills. This often has major impacts in-crop where we get delayed emergence in small patches where the drill has been set for about an inch deep and some shanks are seeding down to two and a half to three inches. The seeds in those trenches are going to be delayed on emergence and that can follow throughout the whole season in terms of the evenness of the crop — and have areas lagging behind. The opposite is also true, where there might have been some shanks that were spraying the seeds on the surface, which makes the seed available to predators like birds and rodents and, of course, little to no emergence. By taking a few minutes to properly set the drill and ensure shanks are all level before seeding is important and can benefit the crop in terms of maturity and the evenness of maturity.
Seeding rates — Calculating seeding rates using the thousand kernel weight, provided by a seed test or available on seed bags, is one way to improve our ability to hit targeted plant stands. For canola and peas, strive for a population somewhere in the range of six to nine plants per square foot, and for cereals we’re looking for about 20 to 35 plants per square foot, depending on the crop. Utilizing those guidelines to determine the proper population for our geography is very important. We also want to think about seed survivability after seeding, factoring in germination and exposure to the elements. When seeding into cold soil, survivability is going to be slightly reduced, even if germination is high. Typically, survivability is going to run somewhere between 60 and 70 per cent for canola, meaning about 60 to 70 per cent of the seeds planted should emerge. For cereals and pulses, that number will be a little higher, sitting somewhere between 75 and 80 per cent.
Seed row fertilizer — When seeding into cool soils, plants don’t grow very quickly because their roots are still developing. So, proximity to phosphorus is of the utmost importance. I recommend applying 15 to 20 lbs of phosphorus in the seed row for canola, cereals, and pulses, just to ensure accessibility to that nutrient right up front. It’s important to abide by industry recommendations for amounts of seed row fertilizer. There are great guidelines established with both nitrogen in the seed row, phosphorus and potassium, and sulphur. These guidelines include factors such as seed bed utilization and sources of fertilizer, and those guides can be accessed online or from your trusted advisers. Finally, if you’re concerned about your seed row fertilizer, it’s always a good idea to turn your fertilizer off for a few feet in the field and evaluate your stand with no fertilizer versus fertilizer, and see how many seeds may be falling victim to high seed row fertilizer.