Do your homework and take a ‘1,000-foot look’ when selecting varieties.
• By Vicky Boyd,
Only a few decades ago, many growers didn’t think much about selecting soybean varieties and planted whatever the local co-op sold. Today, soybean producers face a potentially mind-boggling array of hundreds of varieties across multiple maturity groups.
To help winnow down the selections, University of Arkansas Extension soybean agronomist Jeremy Ross said growers should take a systematic approach that includes studying how varieties performed in university and seed company multiple-location trials as well as local county agent strip trials and demonstrations.
“You kind of need to step back for a 1,000-foot look and think about several factors before you start looking at individual varieties,” he said. “We’ve moved from having just a handful in any given year that we tested to running 180-250 varieties annually. I can’t keep up with them. The life expectancy of a normal soybean (variety) is about three years.”
Tyler Hydrick, a crop consultant with Hydrick’s Crop Consulting in Jonesboro, Arkansas, tracks the different soybean, corn, cotton and rice varieties his growers plant using the computer program, FieldX. But it only allows him a total of 100 variety entries among all crops.
“I’m so scared for next year,” he said. “As crazy as it sounds, next year I could very easily end up with 100 different soybean varieties.”
To help North Carolina growers, the North Carolina Soybean Producers Association developed an online seed selection tool (https://ncsoy.org/varietyselector/) that North Carolina State University Extension encourages growers to use. It includes data from the NC State Official Variety Testing Program. This year, NC State Extension Soybean Specialist Rachel Vann said they have over 215 varieties in the Official Variety Testing program.
“Our growers can quickly narrow their selections if they know what maturity group they want to grow, and that depends on their rotation and when they plan to harvest,” she said. “I think one of the advantages of having so many varieties available is that growers recognize they can typically find high-yielding varieties with the various traits they need.”
Adding to the confusion is many seed companies market the same variety under different numbers. To help Arkansas growers, Ross has created a cross-reference guide. A Croplan RX4825 MG4 Xtend variety, for example, is the same as Armor 48-D24, Hefty H48X7, Local Seed LS4966X, MorSoy 4846RXT, Progeny P4816RX, Dyna-Gro S48XT56 and Delta Grow DG48X45.
When it comes to working with growers to select varieties for the upcoming season, Ross, Vann and Hydrick take slightly different approaches.
Ross likes to first determine the maturity group or groups growers want to plant. In Arkansas, they typically plant late MG3 to MG 5, although MG4 is the most popular. In North Carolina, it ranges from MG 3 to MG 7. Also factor in your other crops and when they’ll be harvested as you choose soybean maturity groups.
“You don’t want to neglect one crop more than another,” Ross said. “Early beans come off in the middle of rice.”
Vann looks at it slightly differently and recommends growers either stagger planting or choose different maturity groups so not all of their crops will be at the same reproductive stage at the same time. By doing so, growers can spread their risk should a drought, heat wave, hurricane or other hazards occur.
University of Arkansas Distinguished Professor of Crop Physiology Larry Purcell has developed the SoyRisk predictor model (https://agribusiness.uark.edu/decision-support-software.php). Mid-South producers can input a planting date, maturity group, soil texture, irrigation information and goals, such as minimizing risk while maximizing profit. The Excel-based program then predicts yields and profits based on the user’s choice as well as a “maximizing” option. The program draws from 30 years of weather data.
Based on Purcell’s work, Ross said, “Data shows that MG4s have a higher yield potential than 3s or 5s. We need to be growing group 4s – mid to late group 4s – to really get the maximum yield on our varieties.”
Hydrick likes to start with herbicide traits and is heavily influenced by the other crops his growers will plant.
“The first and most important question is what herbicide package do we need?” he said. “That question is more of a farm answer and not a field answer. You have to start from the outside to work in. I don’t care if you want to grow dicamba beans or Enlist cotton. Just looking at it strictly from the bean side, the first question we need to answer is herbicide tolerance.”
Growing dicamba beans alongside a different traited cotton, for example, wouldn’t be a huge concern because cotton has a somewhat natural tolerance to dicamba. But growing another traited soybean adjacent to dicamba cotton could cause issues because soybeans are very susceptible to off-target dicamba movement.
The ultimate herbicide trait choice may boil down to personal preference, Ross said.
“Some people are going to look for the cheapest technology to control weeds,” he said. “Some are somewhat biased to some companies. Depending on what your other commodities are, some people use similar herbicide traits.”
Disease, nematodes, chlorine and soil textures
Following herbicide traits, Hydrick said he looks at soil texture, which involves focusing on individual fields.
“A lot of factors goes into this,” he said. “You have to figure out the maturity and the height of the bean you’re going to plant on that ground. Heavier ground tends not to get as much height. We try to plant a bean that gets taller.”
Then Hydrick will look at whether fields have nematode issues, which can be addressed by collecting samples and having soil tests run. In Arkansas, the Arkansas Soybean Promotion Board has sponsored free nematode tests for the past several years for fields coming out of or going into soybeans the next season. Mississippi State University Extension Service also offers free nematode soil testing through August 2021, thanks to check off dollars and a partnership with the Soybean Cyst Nematode Coalition.
If you farm elsewhere, check with your local Extension specialist to see whether your state offers free nematode lab tests.
“I preach this every year,” Ross said. “Everybody’s got to look at yield, but if you have root-knot nematodes in your field and the variety doesn’t have any tolerance, you’re not going to be able to achieve those high yields.”
In its field trials, the University of Arkansas also screens soybean varieties for tolerance to metribuzin, a popular preplant herbicide. In addition, the university screens for chlorine excluders and implemented a new chloride sensitivity rating system of 1 to 5 in 2019, with 1 being a strong excluder and 5 being a strong includer.
Yield is always a factor that captures growers’ attention, Ross said. But he warns against selecting the top yielder based on results from one location. He compares it to a race horse – it will perform well under optimum conditions, but it will go down quickly if conditions aren’t perfect. A workhorse variety, on the other hand, may not be a bin-buster, but it will produce consistently good results over several locations.
“If you get one that looks good over multiple locations, it’s going to be a good fit no matter what,” Ross said.
Hydrick likes to recommend varieties that have a high floor – those that have strong minimum yields regardless of field characteristics. About 80% of the acreage Hydrick’s Crop Consulting serves is planted to Asgrow 46X6 because it performs well under most conditions.
Ross recommended reviewing university yield trials and not just those from your respective state. Also study the results from universities in neighboring states. In addition, look at strip trials or demonstrations conducted by county agents as well as seed company trials. Results from trials or demonstrations conducted close to your farm also are telling, since they’ll be grown under similar climatic conditions as yours.
Vann agreed. “We try to really emphasize to our growers to look at consistent yields across multiple locations rather than just raw yield in one environment. Ideally, it should be multiple environments and multiple years. It’s just been a challenge for a lot of the varieties, because the turnover is very rapid.”
Once you’ve narrowed your choices to about 10 different varieties, look at how each will fit into schedules for the other crops on your farm and avoid planting just one variety, Ross said.