In Carolinas: Early soybean system not for everyone

Can the success of soybean growers in the Delta, planting early maturing varieties very early in the growing season be duplicated in the Carolinas?

Recently crowned South Carolina Soybean Yield Champion, Johnny Houser, says yes. His state best 69.21 bushels per acre of dryland soybeans are good evidence that the South Carolina grower knows what he's talking about when he talks about early/early beans.

Houser grew his record 2005 crop using Garst 4512 seed, a Maturity Group IV variety, planted the first week in May. “We would like to plant our beans earlier than that, he adds, but we couldn't get into the fields until May.”

When soybeans were at their peak acreage in North and South Carolina, back in the 1970s, Maturity Groups VI, VII and VIII were recommended. New research and the onset of Roundup Ready varieties have lowered those recommendations to Maturity Groups V and VI, though a few later maturity varieties are still grown.

In Arkansas and Mississippi Maturity Group III and IV soybeans grown at about the same latitude as the Carolinas have shown some dramatic yields increases when planted in late March and April and harvested in July and August. Typically, these growers plant 10 or more extra pounds of seed to compensate for early season seedling diseases that reduce stand. And, they have to plant in narrow rows to manage weeds.

There are some compelling reasons for Carolina growers to use similar production systems. However, Clemson University researcher John Mueller cautions that some of the growing conditions that favor this ‘early/early’ soybean production system in the Delta don't exist in the Carolinas.

For one thing, he stresses that the Group IV maturity varieties being used in the Delta were developed primarily for use in the Delta. Though on a comparable north/south position on the map, the environmental factors in the two regions can be dramatically different, he says.

They include seed treatments for early season seedling disease, which adds production costs. And, these are predominantly irrigated beans, which are a rarity in South Carolina, he points out.

The early/early soybeans grown in the Delta are drilled beans on 15-20 inch rows. “If you are restricted to planting on conventional 36-38-inch rows, this system is not likely to work for you,” Mueller says.

“When you see yields on irrigated beans of 60-70 bushels per acre, it gets your attention, if you grow soybeans,” Mueller agrees. The most consistent yield increases in the Delta have come north of Interstate 20, and if the weather cooperates, they have seen some excellent yield increases, stressing that these are different environments on varieties ideally suited to those conditions.

They also have excess irrigation capacity and the timing needed for early season beans fits ideally into other cropping systems. In most years, they can harvest soybeans before they get to corn and cotton, so early/early beans fit well into their harvest times. All these little things add up to a great opportunity for early/early beans, but most of these little things don't apply to South Carolina, Mueller stresses.

Among the advantages of the early/early system is a 30-40 cent per bushel premium price bump that growers see every three to four years for early season beans, and less dramatic early season price increases in most years.

For the 2006 growing season, soybean farmers will start out knowing the carryover stock of beans is the highest ever recorded — high stocks have historically been an indicator of low prices. Though no one can predict with certainty, 2006 clearly has the look of one those years where early season beans may be more valuable.

Nearly as unpredictable, and definitely related to price is soybean rust. If rust becomes a problem in the Southeast, early/early beans stand a much better chance of maturing before the disease reaches the Carolinas. The reason is simple: soybean rust has not infected beans until flowering begins, the earlier the flowering, the less rust inoculum plants are exposed to equates directly with less infection.

With a dismal long-range forecast that calls for even more hurricanes in 2006 than in the record setting year in 2005, early/early beans may be harvested before peak hurricane months of August and September. Regardless of hurricanes, early/early beans will allow farmers to spread out the harvest system and reduce harvest and post harvest risks.

On the downside, early/early beans will be exposed to continued flushes of weeds at a time when plants are slow to cover the rows and help shade out these pests. “By planting narrow rows, growers can reduce the time needed by soybean plants to meet in the rows and shade out weeds,” says Clemson University Weed Scientist, Chris Main. In addition, he adds that narrow rows will allow herbicides to be more efficient, making weed management much easier.

Early season diseases will likewise be a bigger problem in most years in early/early beans. In addition to increasing seeding rates to control diseases, growers should plant varieties that have good stem disease resistance, according to Mueller.

In a two-year test on non-irrigated soybeans, Group VII and Group VIII maturity varieties averaged 36-40 bushels per acre. In the same tests Group V and Group VI varieties averaged 32-35 bushels per acre on beans planted primarily in June. Though soil type and a plethora of other factors make it unfair to compare these yields to Johnny Houser's robust 69 bushels per acre beans, it is clear that there is a yield bump for the early/early beans.

Houser, who grows approximately 1,200 acres of soybeans, has been growing Group IV beans for six years, with varying success. In 2005, he tried some Group III beans, but lost so much foliage, he had to spray for weeds to harvest the crop. “That didn't work too well, pointing out that his Group IV beans were mid to late — 4.3 or better varieties.

Some contend, if you can grow corn in the Carolinas, you can grow Group IV soybeans. Though they see some opportunities for some farms, the Clemson researchers urge growers to carefully consider a number of production factors when making the decision to try early/early soybeans in South Carolina.

Hide comments


  • Allowed HTML tags: <em> <strong> <blockquote> <br> <p>

Plain text

  • No HTML tags allowed.
  • Web page addresses and e-mail addresses turn into links automatically.
  • Lines and paragraphs break automatically.