Finding the nitrogen rate for your farm to maximize productivity, profitability, and environmental performance
This decision support tool leverages data from the Iowa Nitrogen Initiative on-farm nitrogen rate trials with cropping systems modeling. See the optimum nitrogen rate under different scenarios by selection location, anticipated crop year weather, residual soil nitrogen, crop rotation, planting date, and fertilizer/crop pricing.
Choose the location of your field by clicking on the map. You can select a location based on county or by Major Land Resource Area (MLRA).
Select your most recent crop rotation.
Select the 40 year average based on data collected by Iowa State University or customize the weather for spring and summer.
This option incorporates observed weather data for the selected region over the last 40 years.
You have selected an average spring, average summer.
"Residual soil nitrate" refers to the available nitrogen that is carried over from one crop year to the next.
If you are running the tool before the season, select your intended planting date range; or, if you've already planted, select the actual planting date.
The price you pay for nitrogen and the price you market your grain determines your price ratio, which is used to calculate the economic optimum nitrogen rate. Use the table below to select your nitrogen source(s) and its price as well as the percentage of your total nitrogen application for each.
Use the slider to select your estimated or actual grain market price. View today's corn prices.
N-FACT is an ongoing project developed to help users understand, forecast, and evaluate cropping systems performance. Predictions will be updated as new information becomes available. The project investigators and Iowa State University are not responsible for user outcomes. Information from this website can be used in presentations without further permission if used in its entirety and credit is given to the Iowa Nitrogen Initiative. However, we encourage you to inform the project directors. Information from this website cannot be used in publications or other model improvement activities without permission of the project investigators.