In October 2020, Drs. Vann, Naeve, and Conley were funded by USB to facilitate collaborative efforts of Extension soybean specialists across the U.S. This USB project brings together soybean Extension personnel from diverse U.S. regions who will collaboratively investigate BMP’s and subsequently disseminate information using diverse outreach strategies. The USB funding specifically supports bi-annual meetings where high-quality information will be generated (i.e., Extension publications, social media releases, videos). This collaborative group will sustain the goals of this project by leveraging QSSB funding to support localized research efforts that will be integral to providing soybean farmers with the tools and information they need to continue increasing their quality and efficiency, ultimately allowing us to develop and deliver BMP’s on a national scale. As part of the USB contract, multistate collaborative research trials are being planned across the U.S. Because the USB grant does not cover the costs of these trails, this proposal aims to seek funding allowing Iowa State University to participate fully.

Develop and distribute up-to-date, high-quality information to soybean farmers across the U.S. on emerging best management practices (BMP’s) through a national partnership.

It is planned to participate in the collaborative USB project and conduct one or two trials as decided upon by the collaboration. The trial(s) will be conducted at the Ag Engineering and Agronomy Research Farm near Ames, IA.

Updated March 30, 2021:
The multi-state group of soybean agronomists has decided to put a large focus on soybean biological N fixation (BNF). BNF may be the most important economic and environmental process affecting crop production (and certainly soybean production) in the US. Yet, it is only partially characterized. A better understanding of quantities of N fixed and the soil, soybean management, and environmental factors affecting BNF will contribute to the science leading to greater soybean yields, higher soybean quality, lower environmental impacts, and greater returns to US farmers. This research aims to 1) estimate BNF and N budgets in soybean (Glycine max) considering N and S fertilization rates, and 2) build a predictive model for BNF in the United States using environmental data.

At Iowa State University, we are conducting 2 trial locations for this multi-state effort. The locations will be near Ames and Sutherland, IA. The trial will have 5 soybean treatments (plus 1 unfertilized corn treatment) using ammonium sulfate, gypsum and urea to examine the N by S interaction and how that may impact BNF. The unfertilized corn treatment is used to determine how much N mineralization (background) N is available for the location. Soil samples are taken pre-planting for site characterization. Plant and soil samples will be taken at the R2, R4, and R6 soybean growth stages. Soybean phenology, grain yield, yield components, and grain composition will also be determined.

Updated October 19, 2021:
Two field trials were established; one at the Ag Engineering Agronomy Farm near Boone, IA (planted 6 May 2021) and the other at the Northwest Research and Demonstration Farm near Sutherland, IA (10 May 2021). Treatments remained consistent with the spring progress of work. At both trial locations pre-planting soil samples were taken to a 24" depth, soil (0-24") and plant samples were taken at the R2, R4 and R6 timings, grain yield, seed weight, and seed samples at harvest were collected. Because this work is to evaluate soybean N fixation as influence by N and S treatments, samples soil and plant samples were sent to Kansas State University and grain samples were sent to University of Minnesota. Centrally analyzing soil, plant, and grain ensures uniform procedures to make the evaluations across multiple states. Initial plans are in place for a second year of the field trial in 2022.

Updated January 24, 2022:
Year one of this project is considered complete. With plans in motion for a second year covered by a project renewal. Soil and plant samples that were collected were sent to Ignacio Ciampitti (Kansas St. Univ.) and Seth Naeve (Univ. of Minn.) for sample analysis and incorporation into a multi-year, multi-state analysis and reporting. Earlier this month, the Iowa field data collection of stand counts, vegetation assessment, canopy cover, etc. were reported into the larger multi-state database.

In 2021, a similar trend was found at both Ames and Sutherland locations where the 'Full' treatment (150 lb N and 15 lb S at both planting and R3) had significantly higher yields than the untreated control. However, all treatments (urea only - 26 lb N; gypsum only - 30 lb S; ammonium sulfate - 26 lb N and 30 lb S; and full) did not produce a profitable yield response (ie. cost of product and application was greater than yield response times commodity price). The grain yield and grain yield response was greater at Sutherland compared to Ames. This may be an indication that soybean response to N and S application is, at least, partially driven by productivity level. Results on soil nitrate and N fixation have not been analyzed yet.

The economic impact and significance of the outcomes derived from this study will lead to an increased ability for farmers and industry advisors to make better in-season decisions for soybean management. Furthermore, agronomists would be able to learn which soybean growing environments respond to individual management practices to be able to better advise farmers on new or evolving management practices. Overall, this study will lead to continued collaboration between soybean extension specialists from across the U.S., leading to developed of best management practices for resilient productivity and increased profitability in an ever-competitive global market.