There's a new reason to plant soybeans early. Newer varieties yield better than older ones when planted early because they handle harsh field conditions even better.

That's the bottom line of a recent three-year study funded by the Soybean Research and Development Council (SRDC). SRDC is a joint project of the soybean checkoff boards in Iowa and Illinois.

When all the numbers were crunched, older varieties, as expected, had higher yields when planted in early May instead of late May — a 6% advantage.

Here's the new news: Newer varieties did even better — cranking out an 11% advantage with earlier planting.

“The new soybean varieties on the market, and those coming, have been selected under earlier planting conditions,” explains Keith Whigham, Iowa State University extension soybean specialist. “Therefore, they are better- adapted to early planting than those available 10 or so years ago.”

Adds Jim Beuerlein, extension soybean specialist at Ohio State University: “These newer-genetics varieties just flat-out tolerate adverse, early season conditions better. They grow better root systems earlier and are more able to fight off diseases, too.”

Tim Maloney, owner of Agri-Tech Consulting in Janesville, WI, agrees. “The new bean varieties today have definitely been bred to better handle that extra stress of earlier planting,” he says.

That early planting challenge for soybeans becomes an even bigger hurdle with the recent wider adoption of high-residue tillage, including no-till planting.

Seed companies have been touting traits such as “strong early vigor” or varieties especially adapted for no-till or other high-residue situations. Some examples, points out Maloney, are Dekalb and Asgrow. Both promote certain varieties as “residue proven.”

That probably has more to do with no-till or high-residue environments than with early planting. But, with earlier planting, the situation is often the same — cooler, wetter soils, he adds.

“Seed companies are actually breeding enhanced vigor into these new varieties to meet these generally harsher early season planting conditions,” says Maloney, “and these beans seem to love it.”

Many large-acreage growers now have separate planters, or planters and drills, so they can plant corn and soybeans at the same time. And that shouldn't bother growers fearful of planting beans between mid-April and mid-May, notes Whigham.

“Soil temperatures for optimum germination are about the same for both crops,” he says.

Obviously, anything can be carried too far. But from about late April to early May in the Soybean Belt, if soil conditions are good, don't worry about the calendar. Just plant. Most years, say these experts, you'll harvest more beans by being an early bird planter.

One caution: If bean leaf beetles have been a problem, remember that they tend to attack the earliest planted fields, says Beuerlein. So watch them. Normally, beans will grow out of the damage. But he says to spray if necessary to avoid bigger problems in the fall.