Allen LeGrand doesn't see better yields from late Group 2 soybeans. But with a 30-40¢ better price for the earlier-maturing varieties and an improved overall harvesting season, the sooner they're planted the better.

LeGrand's Madisonville, KY, farm is on rolling hills and creek bottoms 50 miles south of Evansville, IN, and the Ohio River. The silty clay loam land is normally in a 50-50 corn-soybean rotation. Roundup Ready beans are drilled no-till in-to “green stuff” (weeds), which is killed after the first glyphosate application, he says.

The region is traditionally a Group 4-5 area, where yields average 40-50 bu./acre. However, LeGrand strayed from the norm over a decade ago. “I like Group 2s because it allows us to cut close to 40% of our soybeans while the corn is still drying in the field,” he says. “The Group 2 varieties yield in the mid-40s and nearly as well as 3s and 4s.”

BUT HIGHER YIELDS aren't necessarily his goal for the early varieties. And probably shouldn't be, according to research by University of Kentucky (U of K) Crop Scientists Dennis Egli and P.L. Cornelius.

The studies, reported in Agronomy Journal, indicate that average yield doesn't change as planting is delayed from mid-April until late May or early June. “Thus, there was no evidence that April plantings produce higher yields in any of the three regions,” says Egli. “Early April plantings (but not early maturing varieties) were included in the Deep South (research), and average yields decreased for these ultra-early plantings.”

The conclusion of the studies is not the opinion of other soybean specialists, who promote early planted soybeans to enhance production. Trey Koger, agronomist and soybean specialist, Mississippi State University, says growers in Mississippi and neighboring states enjoy a number of benefits from planting early and using earlier maturing varieties.

“We plant the earliest crop in the country in Mississippi,” he says. “We plant most in April — roughly 80% of our soybean crop” (although 2009 saw delayed plantings due to heavy spring rains).

Larry Heatherly, former USDA soybean specialist and adjunct professor, University of Tennessee, adds that “higher yields result from the more favorable climate associated with development of early planted, early maturing beans in the South.”

LeGrand is like other southern growers concerned about wet weather hampering maturity and harvest as they are with yields. In Mississippi and Louisiana, for example, more Group 3s are seen because they can be planted and harvested earlier to hopefully escape September rains that dampen the region and promote excessive vegetation and seed rot.

LeGrand's diversified bean program helps in more ways than one. “We start by planting late 2s — either 2.8 or 2.9 — in late April after we finish planting corn,” he says. “We then come back with a 3.7 maturity, then a 4.4 and a 4.8.

“We're able to start our bean harvest in late August or early September, when we can make sales based on the (Chicago Board of Trade) September soybean futures price.

“There's usually a good premium for September over the November price. And there can be a 30-40¢ better basis by selling before the bulk of the beans hit the market.”

Just as important is his ability to spread out harvest. “We get to start harvest earlier,” he says. “The corn dries down more in the field, so we don't have to dry it in the bin. If we have a normal fall, we finish harvest by Halloween.”

LEGRAND IS CERTAINLY sold on the early planting program. Planting dates and maturities should be determined by a grower's particular location, climate and overall crop rotation that can cause in-season and harvest problems, says Heatherly.

Egli says there's no harm in planting early if soils are ready. But he still contends higher yields shouldn't be expected.

Most soybean agronomists, however, disagree and promote early planted, early maturing soybeans in the South and into much of the Corn Belt.

“Early planting does a lot for us,” says Koger. “We avoid more insect pressure, take advantage of the cooler weather in the spring and get the crop further along before dry summer periods arrive.”

Koger notes that regional bean yields have doubled the past 25-30 years. “In the 1970s and 1980s our average yield was 22.1 bu.,” he says. “Now it's over 40 bu. That's due to earlier planting, as well as better varieties, more irrigation, best insect management and more scouting.”

Heatherly says the early planting allows the earlier-maturing varieties to miss much of the normally dry and hot months of July and August. “Early planted, early maturing varieties will likely avoid rust invasions that don't occur until late July and beyond,” he says. “And they will avoid the usual onslaught of late-season foliage-feeding insects that are always a problem in the South.”

Some 18 years of research headed by Heatherly at the Stoneville, MS, USDA research center illustrates how different maturity groups in an early soybean production system (ESPS) out-performed a conventional soybean production system (CSPS).

In the ESPS system, irrigated Group 4 varieties planted before April 16 with 140 days to maturity averaged 61.5 bu. That was 1.6 bu. higher than Group 4s planted from April 16 to May 1 with 136 days to maturity. Group 5s planted before April 16 with 160 days to maturity averaged 56.6 bu., compared to 53.7 bu. for 5s planted from April 16 to May 1.

In comparison, varieties planted in the CSPS May 1 all yielded lower. Group 4s planted between May 1 and 16 with 127 days to maturity yielded 54 bu., compared to 46.7 bu. for varieties planted May 16 to June 1 with 120 days to maturity, and 36.5 bu. for beans planted after May 31 with 98 days to maturity. Group 5s yielded from 48.6 down to 37.8 bu. in the three planting periods. Group 6s yielded 43.7-49.2 bu.

Similar results were seen in Heatherly's dryland ESPS and CSPS studies. The earlier-planted bean yields were about 4-6 bu. higher (with a high of 40.6 bu./acre) than those planted after April 16. The CSPS yields were about 12-15 bu. lower.

“Many years of research lead to the unequivocal conclusion that early planting is preferred in the South,” stresses Heatherly.

Egli says that growers considering Group 2 soybeans for harvest and market advantages can grow them on most soils in Kentucky, but they might do better by planting them on drought-prone soils.

Even though the U of K scientists recommend that growers hold their percentage of Group 2s to a minimum, LeGrand is content with his Group 2s in the 30% or more acreage range.

“I've done it for 12 years and have never really found any disadvantages to it,” he says. “It spreads out my work load and improves my marketing capability.”