Iowa Secretary of Agriculture Mike Naig and the Iowa Nutrient Research & Education Council (INREC) today announced the expansion of the Nitrogen Soil Sampling Project that delivers free nitrogen soil testing for farmers in counties upstream from the Des Moines and Cedar Rapids metro areas.

The Nitrogen Soil Sampling Project, originally launched in April 2026, was well-received by Iowa farmers and sign-ups filled up quickly. Because of the program’s popularity, INREC is doubling the project capacity for fall 2026 and expanding the program area to include farmers in all 22 counties in the Greater Des Moines watershed, in addition to four counties in the Middle Cedar watershed. The three-year pilot program is designed to assess year-over-year variability in nitrogen availability and evaluate how on-farm management decisions are impacted by residual soil nitrogen.

“As farmers continue to navigate a challenging ag economy, many are searching for tools to optimize their fertilizer and input costs, while supporting ongoing efforts to improve Iowa’s water quality,” said Secretary Naig. “One soil sample represents a snapshot in time, and this multi-year Nitrogen Soil Sampling Project is designed to help farmers track patterns and better understand how weather and growing season variability affects the residual nitrogen levels in their soils. When the soil sampling data is coupled with the N-FACT tool, farmers can make more informed fertilizer management decisions to minimize costs while maintaining yields and delivering water quality benefits.”

Soil testing for residual nitrogen can help farmers refine fertilizer application rates, which may trim crop input costs while offering water quality benefits. Farmers in the following counties are eligible for the INREC fall soil sampling cost-share project: Audubon, Benton, Black Hawk, Boone, Buena Vista, Calhoun, Carroll, Clay, Dallas, Dickinson, Emmet, Greene, Grundy, Guthrie, Hamilton, Hancock, Humboldt, Kossuth, Palo Alto, Pocahontas, Polk, Sac, Tama, Webster, Winnebago and Wright. The goal is to collect samples from 250 farm fields. Soil sampling and laboratory testing is being led by SoilView.  

Farmers who enroll are asked to provide data such as nitrogen management, crop rotation, cover crop history and manure application, and complete a post-harvest survey. All entries are shared anonymously with researchers at Iowa State University to refine recommended rates using the Iowa Nitrogen Initiative’s N-FACT.

Farmers can start enrolling in the fall soil sampling project now at iowanrec.org/nitrogen-soil-sampling-project.