If Randy Dowdy can do it, soybean farmers in North Carolina certainly can.

So says Brandon Harrelson, sales manager for Southern States Cooperative in North Carolina, speaking of Dowdy, the Brooks County, Ga., farmer who achieved a yield of 116.5 bushels per acre on irrigated soybeans last year.

“We all know who Randy Dowdy is and we all want to know what he does to make 500 bushel corn and 100 bushel soybeans,” said Harrelson at the Southern States high yield soybean field day Sept. 15 at Mount Olive, N.C.

At the field day, participants toured Southern States’ 50-acre, high-yield test plot on Ralph Britt Jr.’s farm. The irrigated plot utilizes an early production system with the goal of achieving 100 bushels per acre. “We’re trying to think about new ways to manage soybeans and what we can do to achieve big yields,” Harrelson said.

“We wanted to use an early production system and make it successful in North Carolina. We wanted to use different products to see which ones would aid us in our successful plot. We wanted to use best management practices available for higher yields. We wanted to show that 100 bushels per acre could be achieved and recorded in North Carolina,” he said.

This year, the test plot presented a number of challenges, including a later-than-wanted planting date, but Harrelson is confident they will reach the 100 bushel per acre goal once it is harvested in November.

“We planted on May 26. Our beans should have been in the ground in late April, but rains kept us out of the fields until May,” Harrelson explained.

Lodging was a problem because 50 pounds of nitrogen was applied at one time. “We didn’t intend for that. We intended to spoon feed the nitrogen, but we forgot to turn the pivot off so we got all of our nitrogen at one time, which didn’t help our lodging issues,” Harrelson said

In the test plot, Harrelson, Britt and the Southern States team planted Southern States 4917, a Group 4 variety that Dowdy also planted on his farm to achieve the 116.5 bushel yield. Harrelson said 135,000 seeds were planted per acre and he is confident that 90 percent emerged. Seeds were planted in 15 inch rows.

“The only reason we decided to plant a Group 4 was that it was an indeterminate variety. We knew that it had genetic potential to continue producing a strong yield even after flowering and pod fill,” Harrelson explained. “Indeterminate varieties have an overlapping range of vegetative and reproductive stages. That’s good because you’re continuing to produce yield during flowering and continuing to produce leaves which are the creating energy, even during the reproductive stages.”

Soybeans had not been planted on the test plot land for several years which is why seed treatment inoculants were important, Harrelson said. “We used an inoculant in the planter box. This is a great thing to do if you plant soybeans on a piece of land that hasn’t had beans for several years. It really helps fixate nitrogen.”

Nematicides and fungicides were applied as preventive measures. In addition, 30 pounds of pre-plant nitrogen was applied. Although soybeans do fixate their own nitrogen, Harrelson said nitrogen needs to be applied if a farmer wants to make a yield of 60 bushels per acre or more.

Need right fertility for higher yields

“If you want 50 to 60 bushel yields, you probably don’t need to apply nitrogen,” he said. "If you want to get 60 to 80 bushels you need to put out 30 pounds of nitrogen. If you really want to push it and go for 80 to 100 bushels, you probably want to look at 30 to 60 pounds of nitrogen. It can’t fixate enough nitrogen to feed it the entire year and continue to grow.”

Potash, potassium and sulfur are also critical as is a full package of micronutrients, manganese and boron.

“It takes a lot of potash. We want 200 units of potash available to the plant in pre-plant fertilizer. We also put out 1,500 pounds of gypsum, and sulfur is important to soybeans as a soil conditioner,” Harrelson said.

Irrigation is critical for achieving 100 bushel per acre yields and was utilized on the Southern States plot.

“If we didn’t get rain in three or four days during the vegetative stage, we usually turned the pivot on. During bloom, a critical time, we wanted to save all of our pods. We didn’t want any blooms to shed so we basically added about 1.5 to 2 inches basically every week. We figured out how much rain we got and decided if we needed to add extra water,” Harrelson said.

As for weed control, the team followed the adage of “starting clean and staying clean.” Harrelson said the goal was to keep the field as clean as it can be until the canopy closes.

“Insect and weed control has to be managed. If we wait until we see disease and insect damage, we’ve already lost yield,” he added.

Ralph Britt is confident the plot will reach or even exceed 100 bushels per acre.

Southern States plans another high yield soybean plot next year, and Harrelson says they plan to shoot even higher than 100 bushels in the next trial.  “We learned a lot and will do some different things. We may look at a starter fertilizer to increase our chances of a more uniform stand and we may look at using growth regulators to help with some lodging issues,” he said.

As for Britt, he noted that mistakes were made along the way and he acknowledged that the later than wanted planting date was a challenge, but he is confident the plot will hit or even surpass the 100 bushel goal once he runs the combine.

“We learned a lot about a high yield system and it helped us to think about doing things differently to increase our yields. I am looking forward to running the combine and the yield monitor to see how we will do,” Britt said.