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Research Highlights

Research Highlights
Achieving 100-Bushel-Per-Acre Yields in South Dakota

By Barb Baylor Anderson

Ongoing research funded by the South Dakota Soybean Research and Promotion Council to try to reach 100 bushel-per-acre soybean yields has identified ways to improve best management practices that maximize yield potential. But, more importantly, one of the principal investigators says it confirms South Dakota farmers must consider yield and profitability together.

“The question of reaching 100 bushels per acre needs to be changed to how do farmers increase yields and profitability simultaneously,” says David Clay, distinguished soil science professor with South Dakota State University. “For example, last year resulted in extensive flooding across the state with a risk from diseases. To reduce potential yield losses, many farmers asked if fungicides should be applied to all fields or only to areas with a high risk. The answer must consider expected economic returns of the control measure.”

To field test different strategies in 2019, South Dakota state agronomists helped farmers assess control approaches on their farm.  Information on expected yield losses and control measures is at https://extension.sdstate.edu/igrow-soybeans-best-management-practices-soybean-production

“On-farm results showed benefits from fungicide treatments were mixed and depended on many factors including product, timing, disease incidence and location,” says Clay. “For disease and other factors, on-farm testing can help producers identify their best chance for success. We share those findings for other farmers through a website located at https://www.sdsoybean.org/.”

On-farm recommendations previously were obtained for assessing soybean seeding rates, planting dates, planting spacing and seed treatments. Clay notes the locally led production and management approach is a good technique because increasing yields without breaking the bank in a highly variable environment is difficult. It requires unique development of adaptable systems that link advances in crop genetics with improved understanding of environmental conditions.

“With on-farm disease control, fungicide treatments showed success can vary from one location to another. We learned remote sensing can identify where positive response would be expected and is useful because disease changes the reflectance characteristics of the plants,” he says. “By understanding this, variability can be used to reduce costs while improving yields. Once problem areas are identified they can be scouted, and appropriate prescriptions developed.”

White mold in South Dakota production field (left). The center image was collected with a UAV and the right image was collected with the Landsat satellite. These images show that the ability to detect differences depends on spectral resolution.

Clay says future work may include testing and assessing the value of unmanned aerial vehicles (UAVs) for identifying yield limiting factors. Such assessments, when combined with on-farm testing of different products, may assess effectiveness just as remote sensing has done for weeds, nutrients and diseases. Other research needs include use of soil and plant biological products that increase yield and soil microbial diversity, cover crops and rotational diversity, where and when seed treatments are needed, soil health, use of drones to improve scouting efficiency, optimizing plant populations for minimizing pests and tracking new pests and pest resistance.

“The purpose of the on-farm program is not to increase yields but to help and provide training to farmers interested in increasing yields and profits simultaneously,” says Clay.

Additional requirements for optimizing yields and profits are discussed in “Igrow Soybean: Best Management Practices for Soybean Production at https://extension.sdstate.edu/igrow-soybeans-best-management-practices-soybean-production.

To find research related to this Research Highlight, please visit the National Soybean Checkoff Research Database.