Bigger soybean yields start with penciling in an early planting date. Unlike corn, beans don't pay much attention to heat units. When the summer solstice arrives and day length begins to shorten, beans shift from vegetative to reproductive growth regardless of whether they were planted the third week in April or the first week in June.

An early planting date can easily add 10 bu. to your yield, but assuming a 20-bu. increase isn't unreasonable, according to growers who have backed bean planting into late April.

In 2007, Mead, NE, farmer Ben Deerson started planting beans on May 3. “The further our planting dates got from May 3, the more the bushels went down,” he says.

So, in 2008, Deerson planted his first beans on April 23. “It was cold. No one but us was even planting corn,” says Deerson, who farms with his father David. “It got everybody talking. Those beans actually came up before the corn we'd planted 4-5 days earlier.”

At harvest, Deerson pulled three separate yield checks out of the 40-acre field and logged yields of 79.3 bu., 78.9 bu. and 79.1 bu. — just shy of his 80-bu. goal. Wet spots in parts of the field brought the yield average for the entire field down to 72 bu.

BY COMPARISON, Deerson used to start planting beans around the third week in May, and a 60-62-bu. yield would be “a really good year.”

Farmers who plant soybeans early talk about “building a bigger factory,” Craig Marsh, Golden Harvest agronomist at Crofton, NE, explains. “Beans need as much vegetative growth as possible before the summer solstice. Flowers form at each node and become pods. The more pods, the more beans.

“Sometimes guys look at later-planted beans that are just as tall as early planted crops and assume they have the same yield potential. But the later-planted beans have fewer nodes that are stretched farther apart,” he says.

But, it takes more than early planting to maximize soybean yields, Marsh says. It takes a change in attitude. “We've got to stop thinking about soybeans as a secondary crop and start thinking of them as a high-value crop,” he says. “You can't just throw a naked bean out there and not look at it again until harvest.”

It starts with seed. “Farmers are willing to buy expensive corn genetics and wouldn't think about planting seed that isn't treated,” he says. “But with beans they look for inexpensive seed and consider seed treatment optional. And, they tend to select an early variety so they can get beans out ahead of corn harvest, rather than choosing the variety with the greatest yield potential.”

IN DEERSON'S EARLY planted beans, he chose a Group 2.8, glyphosate-tolerant NK bean variety that has been a consistent high-yielding bean for a number of years. The seed was treated with CruiserMaxx for early season disease and insect control. “If you don't use Cruiser, the early flushes of bean leaf beetles will just chew the crap out of the leaves,” he says. “You can see the dead beetles on the ground.”

The early planted beans were on pivot-irrigated ground, says Deerson, who is a Golden Harvest seed dealer. “For dryland beans you have to choose a later-maturing variety if you want to plant early. Dryland beans need August rains to make top yield, so I used a Group 3.4 bean on those acres.”

Some growers worry about the risk of frost with beans planted in late April, but Deerson was confident with the odds. “It takes a minimum of three hours at 28° to kill a bean plant. In eastern Nebraska there's only an 8% chance of a freeze after April 25,” he says. “And Syngenta will replace any seed treated with CruiserMaxx for free if you lose the plants to frost.”

Yield studies show that early season weeds can rob yield, so Deerson planted beans in 15-in. rows and used a pre-emerge herbicide to control weeds until the plants canopied. “I sprayed glyphosate twice before the beans began to bloom,” Deerson says. “You lose yield if you spray glyphosate when beans are blooming. The plant has to metabolize the herbicide and that's less energy it has to put into plant growth. That can reduce yield by as much as 5%.”

Deerson hired an aerial application of Warrior and Quadris the first week in July as a preventative treatment for insects and disease. In the first week of August, he sprayed the beans again with Lorsban for aphids, after scouting the field.

“It cost $27/acre to have the fungicide aerially applied. Whether it helps or not probably depends on the year,” he says. “You get the most bang for the buck from a fungicide treatment if it's cloudy and humid. If it's hot and sunny you probably don't need it.”

According to Marsh, scouting fields individually is still the best way to make insecticide and fungicide decisions. “You have to be smart about it,” he says. “But, sometimes farm size dictates a blanket treatment. And, a fungicide treatment adds the security that plant health will stay good until die down.”

The benefits of early planted beans justified Deerson buying a second planter. “We had been using a 16-row, 30-in. planter for corn and beans. I bought a 32-row, 15-in. planter so I can put in beans while dad plants corn,” he says. “It's a bigger planter than what we really need, but I've got some other farmers interested in early planted beans so I'll use it to do some custom work.”

One drawback to early planted beans, according to Deerson, is they don't work well with no-till. “If you're going to plant early, you've got to get that soil warmed up. We're usually 100% no-till, but I disked fields this fall that we want to plant early next spring.”

If farmers are willing to make changes, Marsh is convinced soybeans will reward their efforts. “There are too many guys doing the same thing over and over and wondering why their beans don't yield better. We've got to get it in everybody's head that you get what you pay for,” he says. “Soybeans operate a heck of a lot differently than corn does. But if you're willing to manage the crop, 80-bu. beans are a reasonable goal.”