Iowa Nitrogen Initiative

Nitrogen fertilizer is among the most critical inputs to crop production – and one of the costliest. When applied at the optimum rate, nitrogen boosts productivity and profitability and avoids the environmental costs of excess application. However, finding the optimum application rate can be a challenge: it can vary by more than 100% from field-to-field and year-to-year.

What

The Iowa Nitrogen Initiative is a private-public partnership that provides Iowans with the best nitrogen science in the world for the benefit of productivity, profitability, and environmental performance. Since 2022, we have conducted over 1,000 on-farm nitrogen rate trials on private farm fields across the state of Iowa.

How

We are working alongside agricultural service providers, farmers, and their advisors to design, execute, and interpret hundreds of coordinated on-farm, scientifically robust nitrogen rate trials every year. These trials provide data that helps us understand the interactions among genetics, weather, soil type, and management, and how those impact cropping system outcomes.

This on-farm data infrastructure will allow ISU to use the latest advances in super-computing and quantitative modeling to forecast best management practices and demonstrate how Iowa farmers can maximize efficiency of their dynamic operations.

N-FACT

N-FACT (Nitrogen Fertilization Application Consultation Tool) is an online tool powered by INI trials data and the Agricultural Production Systems sIMulator (APSIM), an advanced cropping systems model. N-FACT allows users to select inputs based on their farm and management decisions, including location, crop rotation, growing season precipitation, post-harvest soil nitrate, planting date, and market prices for corn and nitrogen. Based on these inputs, N-FACT outputs probability-based ranges of optimum N fertilizer rates.

N-FACT also hosts an INI trial data explorer that allows users to observe, benchmark, and compare optimum nitrogen rates across different locations, years, and managements. It can be accessed at https://n-fact.ag.

Together, these tools provide new information that allows users to improve nitrogen management for productivity, profitability, and environmental performance.

Recruiting Farmer Collaborators for 2026

Would you like to better understand and predict the optimum nitrogen fertilizer rate within and across your fields? We’re looking for farmers to participate in our field trials for 2026. Read our trial flyer for more information about eligibility, trial protocol, and benefits.

Iowa Nitrogen Initiative Annual Report

Each spring, we publish an annual report detailing what we learned in the previous crop year (April through March). Click to access the 2024 Crop Year in Review; contact us if you would like print copies for distribution.

 

Forecast and Assessment of Cropping sysTemS (FACTS; 2015-present)

FACTS is an ongoing project developed to forecast and evaluate real-time soil-crop dynamics in specific ISU fields. Predictions and measurements will be frequently updated as new information becomes available during the growing season.

What we do:

  • During the growing season we provide real-time measurements and forecasts for weather, soil water and nitrogen, crop water and nitrogen, yield predictions, crop stage and heat/frost stress.
  • Before/after the growing season we benchmark production, economic, and environmental performance, estimate the yield gaps, and perform what-if scenario analysis to identify management practices with the highest profits and lowest environmental impacts.

Why we do it:

  • To provide quantitative answers to questions that farmers commonly ask such as what is going to be the yield this year, how much nitrogen is in the soil today, do I have enough soil water for the next few days, what if I had used more nitrogen, planted more seeds, gotten more rain.
  • To improve the science behind predictive tools, ground-truth predictions, and explore different approaches to accurately forecasting yields.