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ISOFAST can help farmers well before the tipoff to the growing season

Article cover photo
An online tool can help farmers make decisions based on historical on-farm replicated field trials. ISOFAST is unique and available for anyone to use. (Photo: Joseph L. Murphy/Iowa Soybean Association)

By Suzanne Fey, ISA Data Analyst

Farmers have bigger bets on the line than guessing which college basketball team makes it to the national championship. The Iowa Soybean Association’s (ISA) online Interactive Summary of On-Farm Strip Trials (ISOFAST) offers growers an edge on knowing whether specific products and practices will pay off.

ISOFAST is an interactive tool used to visualize and summarize data from historical and current on-farm replicated strip trials. It is unique, online, user friendly and available for the public to use. ISOFAST is on the ISA website under the Research Tools and Services tab.

The tool’s capabilities are comprehensive, providing:

  • Dynamic, visual summaries for tested individual products and practices;
  • Weather, soils and field management effects to explain yield responses;
  • Intuitive statistical inferences;
  • Break-even economic analyses;
  • Summaries of key scouting, soil and tissue observations for tested treatments; and
  • Short summaries to aid in farmer and agronomist decision making.

The tool is based on independent data measuring yield response in about 4,000 on-farm trials across Iowa from the last 10 or more years. The ISOFAST summaries promote a better understanding of the agronomic and economic impacts of treatments in different conditions across the state. They also can help farmers, researchers and industry to make smarter agronomic decisions and risk mitigation assessments.

Figure 1 shows how users can enter the grain market price and the estimated application cost of the product or practice on the left. ISOFAST will calculate: (1) break-even yield response in bushels per acre required to pay for the treatment; (2) the probability of exceeding the direct application cost across different environments; (3) the range in expected profit to exceed the application and treatment costs.  

Figure 1. Economic analysis of application costs compared to grain market prices.
Figure 2: Comparison of six foliar applied fungicides on soybeans across Iowa from 2005 to 2017. The graphs indicate confidence intervals for yield response in individual trials (small stars) and across trials (big stars).

ISA’s On-Farm Network® has worked with Iowa farmers to conduct hundreds of replicated strip trials testing different fungicides on corn and soybeans. Each of the graphs in Figure 2 illustrate average yield responses (small stars) in individual trials and their corresponding 90 percent confidence intervals for six of the common fungicides. The large red star indicates averages across trials for each fungicide. A yield response is significant if the whiskers of the 90 percent confidence interval do not cross the red vertical 0 bushels/acre yield response line. The gold dashed vertical line indicates break-even bushels/acre to cover application costs.

Row A in Figure 2 indicates the number of trials with significant response to foliar fungicide, while Row B indicates the chance to exceed the break-even cost for using the fungicide. Even if yield responses are statistically meaningful, a positive economic return to foliar fungicides is not always warranted. See the “Stratego YLD” graph in Figure 2.

 Combining individual trial locations, overall study results, weather condition information and economic evaluation will help predict better future performance of specific practices.

Read more about ISOFAST and how to use it in the ISA 2018 Research Annual Report

Use ISOFAST to see results on dozens of products.

See the Analytics team PowerPoint slides from the 2019 Farmer Research Tour.

Contact Suzanne Fey at

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For media inquiries, please contact Katie Johnson, ISA Public Relations Manager at or Aaron Putze, ISA Communications Director at

For permission to republish articles or to request high-res photos contact Aaron Putze at Iowa Soybean Association | 1255 SW Prairie Trail Pkwy | Ankeny | IA | 50023 | US

©2018 Iowa Soybean Association On-Farm Network®. All rights reserved. On-Farm Network® is a registered trademark of the Iowa Soybean Association, Ankeny, IA.Portions of some On-Farm Network trials are paid for in total or in part by the soybean checkoff.