Practices and technologies to increase soybean yields with nitrogen efficiency
There are few things more satisfying than a lush green field of soybeans laden with pods. To enhance the crop—and maybe increase yield—farmers have used inoculants for many years.
As a legume, soybeans have the ability to fix nitrogen in the air to help them grow. They also work with the bacterium B. japonicum, a rhizobia species, which form nodules on the roots of the plant.
“The soybean plant and the rhizobia develop a symbiotic relationship, and in exchange for nitrogen, the bacteria get sugars to live,” explains Shawn Conley, University of Wisconsin soybean specialist.
Without the bacteria in the soil, soybeans can’t properly grow. To ensure the rhizobia are present at planting, Conley says farmers can use inoculant to provide a dose of the bacteria.
Inoculants were initially created to produce an environment for successful soybean growth. Thanks to research, enhanced inoculant formulas now increase yields as well.
“In my opinion, there’s just certain things in production agriculture I consider no-brainers,” says Bill Darrington, Persia, Iowa, farmer. “When you understand what inoculants do, they pay off.”
One recent improvement in inoculant technology is better nodule quality, says Pete Hayes, vice president of marketing for Advance Biological Marketing (ABM). The company’s triple stack rhizobia strains provide healthier nodules, which lead to more nitrogen uptake and higher yields.
In addition to their triple strain technology, ABM also offers a new biological called trichoderma.
“Trichoderma is a fungus that acts in the root system of a plant and grows with the plant,” Hayes says.
ABM pairs trichoderma with soybean inoculants, which results in larger roots that allow the plant to adapt to environmental stresses and increase yield.
“I’ve done side-by-side comparisons for the past six years and have always seen a positive yield response,” says Tim Renger, Bancroft, Iowa, farmer.
After using Graph-Ex SA, which includes the rhizobia and trichoderma, for the past four years, Renger has seen 1.6 bu. to 4.8 bu. increases.
Other companies, such as Verdesian Life Sciences, continue to research and develop nitrogen-maximizing products for soybeans.
“Our newest product, Preside CL, uses a combo of Take Off technology and rhizobia,” says Kurt Seevers, technical services manager for seed treatments and inoculants, at Verdesian. “Take Off is a nitrogen assimilation product, not a preservative, and works inside the plant to use nitrogen more efficiently.”
After one year of research, Seevers says they saw a yield increase in 90% of 16 different test sites. This was compared to long-term averages of other inoculants, which provide a yield benefit 67% to 70% of the time.
That response translates into an average of 2 bu. more than other inoculants and 4 bu. more than untreated fields. Verdesian started offering Preside CL to farmers in 2015 and will continue their research on nitrogen efficiency.
To help farmers produce more with less, Novozymes offers two different inoculants—both have the necessary rhizobia and a signaling molecule. This molecule helps the plant get the required nutrients earlier in development and advance nodule formation for more nitrogen fixation, explains Shawn Semones, director of research and development at Novozymes.
Novozymes also offers an inoculant called Tagteam that includes a fungus with similar functions to ABM’s trichoderma. It also grows with the plant while making previously unusable phosphorus more available to soybeans, which leads to higher yields with fewer phosphorus treatments.
With the pressure to produce more bushels and maximize nitrogen, watch for even more advancements in inoculant technology.