Everyone is familiar with the vast differences in seed size between canola vs. pulse crops (i.e., peas, faba beans). Did you also know that different varieties of cereal crops also have a different seed size – albeit not as dramatic as oilseeds vs. pulse crops? Environmental conditions during the growing season also impact seed size while being a primary factor of seed quality (i.e., germination).
Reaching the desired plant population (plants per square foot or plants per metre square) has many agronomic benefits. These benefits include: a more uniform plant maturity as fewer tillers develop on each plant, a higher percentage of main stems in the crop, increased weed competition, and potentially shortening a crop’s days to maturity slightly. The main stem of a plant generally has the most yield potential.
To calculate the seeding rate, a grower would require three numerical values for their seed lot. These are desired plant population (plants/square foot), 1000 kernel weight (expressed in grams), and germination. A 1000 kernel weight can be requested from a seed lab or counted at home and weighed. The seeding rate calculation is as follows:
Plants/sq ft X 1000 KWT (grams) / germination (expressed in decimal form) /10 = lbs of seed per acre
Seeding rate calculation example between two years of same barley variety with similar 1000 kernel weight but differing germination values
28 plants/sq ft X 45.1 grams /0.75/10 = 168 lbs/ac
28 plants/sq ft X 45.9 grams/0.99/10 = 130 lbs/ac
Example with same germination value, but differing 1000 kernel weight
28 plants/sq ft X 45.9 grams/0.99/10 = 130 lbs/ac
28 plants/sq ft X 57.8 grams/0.99/10 = 163 lbs/ac
