Maximizing returns on seed corn investments
With rising seed corn costs and continuing genetic improvements allowing for better yields at thicker planting populations, growers may question which population yields the best per acre return.
MSU Extension educators in the Thumb and Saginaw Valley studied optimal corn seed populations in multiple on-farm population studies in 2008, 2009 and 2010. Planted populations ranged from 24,000 to 38,000 seeds per acre with incremental increases of 2,000 seeds. Harvested populations were generally similar to planted populations. The corn was planted in 30-inch rows, and the hybrid Great Lakes 4689GVT3 was used each of the three years. These results represent 54 study replications over three years. It should be noted that these studies were established on high yielding, well-tiled loams and clay loams throughout the Thumb and Saginaw Valley.
Gross per acre returns for each population were calculated using a corn price of $5.60 per bushel and a per bag seed cost of $275. Thus, each incremental increase of 2,000 seeds increases costs $6.88 per acre, and an additional 1.3 bushel per acre yield would be necessary to cover the increased seed cost. See the following table for results.
According to the statistics, when populations were between 30,000 and 38,000, yields were significantly higher than the 24,000 and 26,000 populations at the 0.05 level each of the three years the study was conducted. Corn yields leveled off at populations of 32,000 seeds and greater. There was only a small increase of 0.7 bu./A between the 32,000 and 38,000 populations, which is not statistically significant. At an average yield of 194.0 bu./A, the 32,000 seed per acre treatment returned the most revenue per acre.
The Corn Marketing Program of Michigan provided funding to make this study possible.