If you grow corn, you may contribute to raising a record number of corn plants in 2015. Bob Nielsen, Purdue University Extension corn specialist, says data from on-farm trials and other whole-field trials conducted at other locations indicate rising final harvest populations since 2008.
Nielsen, Jim Camberato and Jason Lee summarized data from 67 field-size trials over the past seven years, going back to 2008. There is no mistake that the average harvest population has been increasing, they conclude.
The estimated final harvest stand in Indiana in 2014 was 30,850 plants per acre, they observe. Their analyses indicate maximum yield occurs at 32,000 plants per acre. Further, back in 2013, the year of the drought, Nielsen estimates that half of all Indiana cornfields had more than 30,000 plants per acre. By contrast, data from 1998 suggests that in that season, only 5%, or one in 20, Indiana cornfields had harvest populations of 30,000 plants per acre or more.
Before you crank up the seeding rate, here are a few observations that might cause you to think.
First, obviously weather affects yield. From the devastating drought of 2012 to each of the last two seasons, yields doubled or more for many fields. Yet populations only increased incrementally. It takes more than corn stalks to produce high yields.
Second, maximum yield was at 32,000, but Nielsen contends that may not be the population that produced maximum economic yield. Seed costs must be counted in. If a bag of seed costs $240 for 80,000 kernels, that's $3 for every 1,000 seeds planted. Will tight budgets cause some to cut back on seeding rate, or will they try to yield their way out of low prices and go to even higher seeding rates? Time will tell.
Third, to get 32,000 plants per acre, if that's your goal, you will need to plant more than 32,000 seeds per acre. How many more depends upon your time spent on planter maintenance and planting conditions, plus management style.
Fourth, variable rate planting is on the rise, and may tend to increase overall plant population. Farmers can plant higher rates where they think soils are more productive.