Variable Rate Seed and Plant Stand Counts
We are often asked: "Why do we variable rate seed?" Our answer is to try to achieve a more even plant stand by increasing the seeding rate in areas that we expect the mortality to be higher, and decreasing it in areas with lower mortality. One of the benefits of having an even plant stand throughout the field is consistent crop staging which helps with spray timing. This is especially important for spray applications that have a very small crop stage window, such as Fusarium Head Blight.
Back in 2012 at CropPro we were not yet doing variable rate seed, and found that plant stand counts varied immensely between zones. We also were nowhere close to the recommended target of 30 plants/ft2.
2013 was the first year CropPro did variable rate seed. The overall seeding rates were also increased to try to target a higher plant stand. When doing plant stand counts that year, we found the counts to be much more consistent across the zones.
Since 2013 we have continued to do plant stand counts on every farm, every year. As we expand to different geographies in Western Canada, the target seeding rates and mortalities may be different. Low rainfall areas in Southern SK and AB may have very different seeding rate strategies and goals than North-East Saskatchewan which is typically a higher rainfall area. Having boots on the ground helps us to learn the individual fields and try to apply the best strategy.
The example below shows a typical field in North East Saskatchewan. In this field the barley seeding rates were increased in zones 1-2 and zones 8-10. Zones 1-2 are the driest parts of the field so we expect that in a low rainfall year there will be less emergence. In contrast, zones 7-8 are lightly saline depressions and zones 9-10 are the highest salinity. We expect the high salinity zones to have the lowest emergence, so we increased the seeding rates the most in zones 9-10 to try to get a crop established.
In summary, plant stand counts are a very important part of our variable rate program. They allow us to use data from the field to manage our recommendations and help our clients reach their target plant stand goals.