Optimal seeding rates for faba beans can vary from less than 3 bushels per acre to over 6 bushels per acre due to a wide range in seed size.
With spring around the corner, Sherrilyn Phelps of Saskatchewan Pulse Growers stresses the importance of knowing the thousand kernel weight of faba bean seed.
“Depending on variety and source, we see a range from 335 gram thousand kernel weight to well over 800 (grams), so that’s more than two and half times difference in size,” she explains in this Pulse School episode.
Seeding Rate Calculations (courtesy SaskPulse)
Target Plant Population = 45 plants/m2
(Target plant population/m2 ) x TKW / emergence rate = kg/ha
Kg/ha x 0.89 = lbs/acre
(Target Plant Population/m2 ) x 0.09 = Target Plant Population/ft2
After plugging the TKW number into the seeding rate formula, the next step is predicting what the emergence rate will be. Phelps suggests using a rate that’s 5 to 15 percent lower than your germination rate, depending on whether conditions are conducive for seed survival.
“So it depends on whether you’re seeding early, if you’re putting it through air-seeding systems with a lot of air, is your seed questionable, are you putting extra fertilizer with it, or doing things that could impact emergence. Under those situations use a lower emergence rate,” she explains, noting she typically uses an 85 percent emergence rate if germination is 90-95 percent or higher.
Phelps also shares these tips for getting faba beans off to a good start:
- Field choice — fabas like moisture, so choose fields with more water holding capacity. Avoid ground where residual herbicides could harm faba beans, and since there’s a high level of outcrossing in fabas (which could result in a mixture of types at harvest), choose fields that are at least 100m (or even 500m) away from other faba bean fields.
- Fertility — faba beans are a high user of phosphorus — up to 40lbs/ac actual can be seed-placed safely. (Sidenote: Fabas are the highest nitrogen-fixing legume grain crop in Western Canada.)
- Inoculant — use an inoculant that’s either specific for fabas or ensure it works on fabas. Not all pea/lentil inoculant strains are effective.
- Seeding date — as early as you can get on the field — they should be the first crop going in the ground.
- Seeding depth — 2-3 inches
More information on seeding faba beans available here