Bean production practices such as row width, market classes grown, and the cultivar architecture have changed over time. Collectively, these changes could have a dramatic effect on grower decisions for plant populations for dry beans. Currently, there is little information on the impact of seeding rate on the yield of large seed dry beans in Ontario, while recent technology now allows growers to change seeding rate in real time, to maximize yield and minimize cost. The purpose of this study was to determine the optimal plant population for large seed dry bean cultivars planted in 38 and 76 cm rows, across multiple environments in Ontario.
Five small plot studies tested kidney (cv. Inferno and Red Hawk), cranberry (cv. Etna) and otebo (cv. Hime) beans in two row widths and four seeding rates. On 38 cm rows the seeding rates were 120,000; 180,000; 240,000 and 300,000 seed/ha (approximately 48,500; 73,000; 97,000; and 121,500 seeds/ac). On 76 cm rows the seeding rates were 76,000; 105,000; 140,000 and 175,000 seed/ha (approximately 30,750; 42,500; 56,650 and 70,800 seeds/ac). Sites were located at Ridgetown and Exeter ON. Measurements included plant growth and development at 40 and 60 days after planting, and crop yield.
Decreasing seeding rates reduced canopy height in both row widths, but plant dry weight increased, particularly in narrow rows. Seeding rate and row width had no effect on plant development at 40 or 60 days after planting, or seed weight at harvest. Crop yield was similar (Figure 1) for both row widths, whereas in past research there was a 13.6% yield increase for narrow row kidney beans versus wide row beans. The lowest seeding rate reduced yield by 12% in wide rows and 10% in narrow rows, while all other seeding rates had similar yield to the highest seeding rate.
