If you’re growing soybeans in the Missouri Bootheel, normally planting maturity Group  IV or V varieties, you wouldn’t dream of importing Group II and III soybeans from Iowa. Or would you?

“That’s exactly what many producers are doing,” said Ron Marler, manager of the Bernie, Mo., MFA Agri Services Center. “We brought in a lot of Group III soybeans last year and they performed very well; yielded in the 60 to 70 bushel range—on a par with our traditional late Group IV beans. And there will be more early maturing soybeans planted this year.”

Researchers at the University of Missouri’s Delta Center, near Portageville, and at the University of Arkansas have worked the past few years with ultra-early soybeans, and results are encouraging.

“Our results show that, in any given year with irrigation, we can have similar yields for MG II through MG VI soybeans,” said Larry Purcell, plant physiologist, University of Arkansas. “Even earlier varieties perform about as well some years, but their yields are less dependable over time. The crux of production with ultra-early soybeans is using narrow rows [drilled at 7.5-inch row spacing] and high population densities. This has been the focus of our research for the past 2 years.”

Early maturing soybeans generally are shorter growing and branch less than longer-season varieties. They need to be planted thicker to have the same yield potential. But how much thicker?

“That’s not so easy to answer, because the agronomic optimum and the economic optimum may not be the same thing,” said Purcell. “And there are differences from year to year. Also, the length of growing season changes somewhat with changes in latitude and growing conditions.”

Purcell’s research shows minimum plant densities—actual plants, not seeding rate—for soybeans planted in May and grown under irrigation to be 325,000 plants per acre for MG I and 101,000 plants per acre for MG II.

“These are the minimum populations we have found that are needed to give near maximum yield,” said Purcell. “However, most growers may want to plant for a higher population, as insurance against risk, and higher populations do not decrease the yield potential. Again, these populations are for May-planted beans. Drought avoidance is better when you get the crop planted earlier, but it’s difficult to get a higher plant population when you drill beans much earlier.”

“Our best bet may turn out to be MG II soybeans,” said Grover Shannon, soybean breeder at the Delta Center. “Earlier varieties don’t handle stress as well as longer-season beans, and they have a shorter time to recover. As things are now, we cannot bring MG II soybeans here from farther north and get along well consistently. They don’t have resistance to cyst nematode and some other diseases, and they often don’t perform as well on some of our soil types. We still don’t have ideal MG II and MG III varieties for the Mid-South.”

But Shannon is working to correct that situation, as is Pengyin Chen in Arkansas.

“We’ve made north-south crosses and are evaluating them now,” said Shannon. “I’m breeding more plant height into them as well as disease and nematode resistance.

We don’t know all of the answers yet, but we’re learning. Within 3 years, we should be releasing ultra-early soybeans that are more adapted to conditions here.”

Early maturing soybeans have some distinct advantages in the Mid-South. Getting the crop planted early and in pod-fill stage before the typical hot dry weather is a big benefit.

Friendlier markets

“Farmers here who planted early varieties in April were able to start combining in August,” said Marler.

In mid-August, 2004, the soybean price was making wide swings in the $5.50 to $6 range. Two months later, as conventional harvest got underway in earnest, prices had dropped by $1 per bushel.

Spreads harvesting chores

Putting the combine to work in late summer spreads both labor and machinery over a longer season.

More cropping flexibility

Arkansas researchers are looking at the possibility of using ultra-early beans in novel double-crop situations—two soybean crops per year, or an early corn crop followed by soybeans on irrigated land.

And there are some potential drawbacks with early maturing beans. For one thing, ultra-early beans are maturing in the hottest part of summer, which may cause more shattering losses.

“Seed cost and availability can be problems, too,” noted Shannon. “Planting at high populations can push the cost of seed to $50 per acre or more. And early planted soybeans should get a seed treatment to prevent damping off.”

While ultra-early soybeans look promising for the southern quarter of Missouri and on southward, Bill Wiebold, University of Missouri soybean specialist, is skeptical about the strategy for central and northern Missouri.

“Some Missouri producers are looking at early maturing varieties as a hedge against Asian soybean rust, but I think they would do better to focus on maximizing their yield potential [with adapted varieties],” Wiebold said. “Do the best job of growing soybeans that you can. The threat of rust makes everyone nervous, but I wouldn’t make a management decision solely on that threat.”

“Rust is a $100,000 question for 2005,” said Larry Purcell. “And it seems reasonable to expect that earlier maturing soybeans may have an advantage in avoiding rust in many years. But my pathologist colleagues tell me that the cooler temperatures and wetter conditions ultra-early soybeans would experience during seed fill would likely be ideal for rust development also. We’ll have a better idea after this cropping season.”

So, wherever you grow beans, if you’re thinking of going ultra-early for the first time, plant early maturing beans on a small acreage to begin with. If it works as well as it has for some Mid-South producers, you can go with more acres next time. If it doesn’t work, you haven’t risked as much.