Early soybeans show promise in Southeast

Soybean producers in Alabama who tried an Early Soybean Production System (ESPS) this past year generally enjoyed better-than-average yields, thanks in large part to ideal weather conditions, says Dennis Delaney, Auburn University Extension agronomist.

The majority of the ESPS soybeans are being grown in north Alabama's Tennessee Valley, says Delaney, although they're also being grown in other parts of the state, including south Alabama's Wiregrass Region.

“The early system has become a viable option for some of our growers, especially now that we have improved varieties. Before, we were trying to grow varieties developed for Tennessee and Kentucky, but these new varieties work well for those of us in the lower Southeast,” he says.

Many growers who planted soybeans in the early system this past year saw yields of 50 to 60 bushels per acre, says Delaney, while some of the later-planted soybeans averaged in the 25- to 30-bushel-per-acre range.

Alabama producers using the ESPS usually plant during April and early May, he says. Delaney cautions growers using the early system that timely harvesting is essential for a successful crop, and that ESPS soybeans are susceptible to pod shattering and to disease. “Growers need to harvest these soybeans quicker, when the pods are ready in August and September. They should stop harvesting corn or whatever else they're doing at the time and get these beans out of the field,” he says.

It's also important, he adds, to use a fungicide on the seed and to use a desiccant for removing leaves and for controlling late weed flushes. “Sometimes, we get rainfall in August and September that causes weeds to come up through the plant canopy,” explains Delaney.

If this past year was any indication, the earlier planted soybeans could be less susceptible to Asian Soybean Rust, he says, since these beans were approaching maturity when rust was first detected in the state.

He estimates that 40 to 50 percent of the soybeans planted in Alabama this past year were of the Group IV variety, while in previous years early planted soybeans made up only about 10 percent of the state's total acreage.

Delaney says he expects a slight increase in Alabama's soybean acreage this year, as some growers move away from corn due to increased nitrogen prices. In 2005, Alabama growers harvested 145,000 acres of soybeans with a 33-bushel-per-acre average yield.

Researchers in Georgia also are looking at ESPS soybeans, planting a Group IV variety between April 20 and May 31. The system, according to Extension specialists, is still fairly uncommon in Georgia.

The ESPS system appears to have the most merit for productive soils in the Middle/Upper Coastal Plain and the Limestone Valley regions of Georgia, according to the 2006 University of Georgia Soybean Production Guide.

The critical moisture period for ESPS is July and early August, states the guide. Therefore, the ESPS system can be used to escape September/October drought and/or to further spread drought risks when grown in addition to regular soybean varieties.

The performance of ESPS varieties can be improved by planting in close-row widths (7 to 30 inches) and at high seeding rates (10 to 20 percent above normal). ESPS varieties will mature by mid-September, and harvest must be made by 10 to 14 days after maturity to avoid shatter and seed quality problems.

ESPS varieties, say Georgia specialists, are ideal for soybean trap crops. They are, however, for the most part, susceptible to root-knot nematodes. Therefore, they should be planted only on select soils. ESPS varieties have high yield potential but have slightly higher production risks than regular varieties, according to the guide.

The three major risks which must be managed when growing ESPS soybeans include:

  1. Early maturing varieties attract stink bugs during early pod-fill (July). Therefore, stink bug scouting and control measures are essential.

  2. ESPS seed quality declines rapidly in the field after maturity. Harvest within two weeks of maturity to prevent possible severe seed quality problems.

  3. Maturity of ESPS soybeans can coincide with late August and early September rains and hurricanes, such as those encountered in 2004. Thus, a large portion of a grower's soybean crop should not be planted in this manner. It is always best to spread risks over planting dates and maturity classes.

University of Georgia Extension specialists say the performance of an ESPS crop has everything to do with weather, and conditions in 2006 were ideal for such a crop, with ample rainfall through early August followed by four to six weeks of dry weather.

While this weather pattern was great for ESPS soybeans, it also was the primary reason statewide yields fell to 26 bushels per acre, they say. This particular weather pattern creates a worst-case scenario for later maturity groups.

Planting an early maturity group in the spring may help to prevent a late-season fungicide treatment for Asian Soybean Rust. However, the Georgia specialists recommend that this type of production system be irrigated.

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