This planter, used to demonstrate several brands of planter units, was used at various speeds to evaluate the effects of planting speed on yield. (Planter and photo courtesy of Case-IH)

May 11, 2007

With the wet and rainy spring, many producers may feel like they're behind on planting this season, yet they should resist the urge to speed up to cover more acres faster. While newer corn planters can singulate the seed at speeds up to eight miles per hour, most planters were designed to properly place the seed in the soil at an operating speed of about five miles per hour.

Table 1. Corn yield as influenced by planting speed at the Rogers Memorial Farm (RMF) and at the Ag Research and Development Center (ARDC).
Speed, mph	Yield, bu/ac
	RMF	ARDC
2.5	157.3	195.2
5.0	160.0	198.3
7.5	152.1	192.2

As planting speed goes up, seed spacing uniformity and depth placement uniformity tends to decrease, reducing yields because of uneven competition among plants. However, any possible yield reduction from non-uniform stands needs to be balanced against any potential yield reductions from late planting when determining planting speed.

In 2006, I had the opportunity to borrow a planter designed to compare the seeding performance of several different brands of planting units. While this planter is being used across the Midwest for seeding demonstrations, it's not set up to compare the effects of planter brand on yield (because of wheel track interactions). However, a yield sample across the width of the planter represents "an average planter" since several brands are on the toolbar. I used the planter at different planting speeds to test the effects of speed on yield. A replicated set of plots were dryland no-till corn into wheat stubble at the UNL Rogers Memorial Farm east of Lincoln. The planter was also used for irrigated corn no-tilled into soybean residue at the UNL Ag Research and Development Center near Mead.

At both sites, the yields were best when the planter was operated at 5 mph and decreased as the speed increased to 7.5 mph. Though just two sets of conditions, the profit loss was more than $20 an acre, considering $3.50 a bushel corn. This is enough to justify renting an extra planter or hiring a custom planter operator rather than speeding up to cover more acres.

Paul Jasa
Extension Engineer