Update:
State collaborators were requested to collect data from fields planted with soybean in 2016. The survey form was distributed among soybean producers in each state, through Extension Educators, extension events and media, crop consultants, state soybean growers’ boards, , etc. Filled forms were sent to the NE-WI core team before May 1, 2017. Total number of surveyed fields was 2339. Taking into account the number of surveys collected during the 1st year of the project, our database contains information from a total of 6251 soybean fields, representing 501,837 acres. Number of surveyed 2017 fields per state were: OH (227), IL (83), IN (77), MI (339), WI (208), IA (315), ND (311), MN (36), KS (101), and NE (642). Number of surveyed fields was very close (or even above) our target number of survey per state and per year. Exceptions were IL, MN, IN, and KS, which were substantially below target (only 15, 9, 25, and 46% of the target number of surveys were collected, respectively). We followed up with these four collaborators to continue data collection during 2017 summer until reaching a number of surveyed fields that is closer to the target.
The NE-WI core team spent substantial amount of time inputting the producer-reported data, quality control measures, mapping of field boundaries, and retrieving weather, soil, and terrain data for each individual field-year case. Follow up with some soybean producers was needed to verify some of their survey entries. We inputted and quality controlled all the data collected in all states. The data were archived in excel format, with columns indicating the different parameters (yield, planting date, etc.), and rows corresponding to specific field x year cases. This file is available to NCSRP upon request. Surveyed fields containing missing yield data or without field location were eliminated from the database. Note total number of surveyed fields indicated above (6251 fields) corresponded to the final database AFTER inputting and quality control. Along the entire process, we were very careful to keep data strictly confidential and never disclose producer contact information.
The team has published a scientific article revealing the major causes for yield gaps in the US North Central Region in the prestigious Agricultural & Forest Meteorology journal (SEE APPENDED FIRST ARTICLE). This journal is amongst the most impactful papers in agricultural sciences and has a massive outreach. The paper described the methodology followed to calculate yield gaps for major soybean producing areas across the US North Central region and identify the underlying factors explaining the yield gaps. Likewise, we published an extension article summarizing the results of the papers (SEE APPENDED SECOND ARTICLE; also available online at: Key Management Practices That Explain Soybean Yield Gaps Across the North Central US. We shared this extension article with NCSRP members, project collaborators, state commodity boards, extension educators, Natural Resources Districts, and other colleagues involved on data collection. Our preliminary findings were also publicized through the SRII website, extension websites and events, newsletters, etc. (e.g., http://illinifarmreport.blogspot.com/2016/02/benchmarking-soybean-production-systems.html; http://www.soybeanresearchinfo.com/index.php?id=36&p=&search=; http://ipcm.wisc.edu/blog/2016/10/calculating-the-soybean-yield-gap-for-wi-soybean-farmers-2/; https://stepupsoy.osu.edu/soybean-production/soybean-yield-gap-research; http://msue.anr.msu.edu/news/survey_to_help_michigan_soybean_producers_identify_and_overcome_yield_gaps; http://ilsoyadvisor.com/agronomy/2017/october/understanding-yield-gaps-to-improve-yield-and-profitability/; Yield Gap Report Back). The team has also submitted a third scientific article for publication in Field Crops Research journal (now under review). This paper assessed the power of different statistical method on their ability to detect the causes for yield gaps. During the last 6 months, we had bi-weekly team meetings to check on project progress and discuss next steps.
We had a whole-team meeting, including all state collaborators, in October 2017 during the ASA/CSSA/SSSA meeting at Tampa FL. During the meeting, we discussed project progress and opportunities to leverage on the output from this research. Our team also gave two oral presentations at this conference based on results from the project. Drs. Grassini and Conley has integrated results generated from this initial analysis into all of their Extension programming this past winter. This includes 60 Extension presentations to ca. 5,000 farmers, crop consultants and industry reps.

We developed a novel approach that combines producer survey data with a spatial framework for identifying causes of yield gap in the US North Central region. We generated a producer survey database containing 6,251 fields and associated yield, input and management data. The analysis indicate that, on average, soybean producers are 22% (dryland) and 13% (irrigated) below their yield potential as determined by climate and genetics. Planting date, tillage, and in-season foliar fungicide and/or insecticide were identified as explanatory causes for yield variation, with the planting date the most consistent management factor that influenced soybean yield. There are also other opportunities to improve producer profit by cutting on inputs cost, for example, by reducing current seeding rates. The approach developed for this project is cost-effective and can help inform and strategize research and extension program at both state and regional levels.