Arkansas farmers could plant twice as many acres of early-maturing soybean varieties this spring as usual, according to Lanny Ashlock, soybean agronomist for the Cooperative Extension Service, University of Arkansas.
He said the reason for the increase is simple — early-maturing varieties planted in April need less water during late July and August. “The reason for the increased interest relates back to the last three growing seasons being very dry. It's an attempt to minimize the impact of drought on soybean production.”
Arkansas farmers raise about 3.4 million acres of soybeans annually. Typically, about 400,000 acres are in early-maturing varieties. Group IIIs and IVs mature earlier in the growing season. The hope is that they will develop and mature while there is adequate moisture. They are ready to harvest in August and early September, when drought can be a problem in many years. The bulk of the crop, in conventional Group V varieties, matures in September and October.
The numbers are on the side of the early-maturing varieties. “For the last decade, the non-irrigated early soybean system has been the most cost-effective and has produced the most yields,” Ashlock said. “They've averaged about 30 bushels per acre, about 5 bushels more than the conventional system. Year-in and year-out, it seems to fit Arkansas' rainfall patterns better than any other soybean production system.
“We've been evaluating the IIIs, and they perform better because of the rainfall patterns we've been seeing. They've done quite well.”
Before farmers decide to grow very early-maturing varieties, they need to know the key factors that make the system work.
“They have to be ready to plant when the weather breaks in April,” Ashlock said. “That can be a problem for growers who are trying to plant rice and other crops. There's a tremendous demand on labor and equipment.” The seed has to be in hand and needs to be treated with a fungicide to minimize pithium problems.
Farmers should consider planting Group IVs and late-maturity Group IIIs in mid-April, when the soil is warm enough to get a stand. Farmers in south Arkansas need to have completed planting these varieties by the end of April. It's not as critical in north Arkansas.
Ashlock recommends that farmers drill the seed in or plant in row spacings not more than 20 inches. In most cases, seeding rates should be increased by 15 to 20 percent. That's about 180,000 seeds, or 60 pounds, per acre depending on seed size.
With early-maturing varieties, weed control is important. Narrower rows and increased seeding rates can help reduce herbicide use. Farmers must be vigilant for the beanleaf beetle and stinkbug throughout the growing season.
Ashlock noted that even though the early-maturing system minimizes the need for irrigation, farmers who can irrigate these beans one or two times in June and/or July, can often double their yields.
“That's a lot more bang for your buck than you get with Group V conventional varieties,” he said. “Nothing seems to respond as well to watering as these early varieties.”
Just as farmers have to be ready to plant early varieties on time, they have to be ready to harvest when the crop is mature, Ashlock said. “It must be harvested just as soon as the crop matures.”
He said a farmer harvesting early varieties in August or early September must make sure he has a “home for the beans.” In other words, the farmer must be able to store it or make sure that an elevator operator has space reserved for the soybeans, Ashlock said.