Determining a Rye Seeding Rate By Counting Seeds
Last week, I helped Gary Guthrie seed cereal rye into plots on his farm near Nevada as part of a variety trial. We recently got some samples of hybrid rye seed donated by KWS, a German seed company. Our target plant population for the plots was 30-35 seeds per square foot. We chose this target based off of what a number of the experts who presented at last winter’s Small Grains Short Course had determined as ideal for winter small grain production.
Before going to the field, I determined the 1,000-kernel weight in grams of each of the varieties we seeded into the plots. I did this by counting out 100 seeds ten times and then weighing them with a small kitchen scale. It probably took me ~20 minutes to do each variety (five in all: 4 hybrids and 1 not-stated variety).
After weighing all the varieties, I used this nifty calculator from Alberta Agriculture and Forestry that David Weisberger, graduate student in agronomy at ISU, pointed short course attendees to last winter. The calculator asks users to input the desired plant density (population), germination rate, emergence mortality and 1,000-kernel seed weight. It then provides the user with the proper seeding rate to achieve the desired population. Germination rates were provided on the bag tag for each variety and I assumed a mortality rate of 10% for each variety.
Look at how the 1,000-kernel weight and germination rate affect the seeding rate! There is a 70-lb difference between the lowest and highest seeding rate to achieve the same target population of 30-35 seeds per square foot. It just goes to show how important it is to determine seed size when determining a seeding rate, especially when you have a population density in mind. Progas had the highest seeding rate because it has the biggest seed among all the varieties (e.g. need to put out more pounds of seed per acre because those seeds are larger/heavier than the seeds of the other varieties).
Gary and I seeded the varieties by hand into small plots measuring 7.5 ft x 25 ft. Here’s how the seeding rates looked at the plot level:
- Bono: 7.6 oz./plot
- Brasetto: 8.5 oz./plot
- Gatano: 6.9 oz./plot
- Progas: 11.7 oz./plot
- VNS: 8.1 oz./plot
So count some seeds (and calibrate those grain drills) when getting ready to seed winter small grains this fall!