Regional Corn Nitrogen Rate Calculator

John E. Sawyer, Faculty, Department of Agronomy


Coordination of nutrient guidelines on a regional basis is becoming more and more important with government programs now crossing state boundaries and with the ease of information access today through the internet by a widely geographically dispersed audience.  Providing current research-based information on nitrogen fertilization rate for corn production helps producers make input decisions and economically reach crop production goals.  Use of the internet to locate production information has become commonplace for producers, crop advisers, and agency personnel.  Providing information in on-line web tools allows for a consistent resource, and readily provides access to new information.


The goal was to provide access to nitrogen rate guidelines for corn production via an on-line calculator tool that is based on the regional guideline approach and from recent nitrogen response databases and economic analysis.  The web based tool is targeted to crop producers, ag-business professionals, certified crop advisers, and state agency personnel.


The publication Concepts and Rationale for Regional Nitrogen Rate Guidelines for Corn was recently developed in cooperation with soil fertility research and extension personnel from seven states in the U.S. Corn Belt.  The on-line web tool ( was developed that incorporated the regional approach into an interactive calculator that uses the research database and user selected inputs to derive a suggested nitrogen rate of application.  Information can be entered by the user to tailor the calculated rate to specific situations, such as state, state geographic area, soil yield potential, crop rotation, corn price, and nitrogen price.  This regional approach allows uniformity of nitrogen rate development, but tailors the rate guidelines to specific state situations.  In the past year the database was updated with new nitrogen response trial data from Iowa and Illinois.  This updating keeps the site current and provides guidelines using the latest research available.  In the past two years, there have been more than 30,000 visits to the corn nitrogen rate calculator web tool. 


Application of nitrogen input is a major expense for Iowa corn production.  Economic payback from any input is essential to maintain economic viability of crop production.  Having a source of research information for producers and crop advisers is essential to making appropriate nitrogen rate decisions.  The web based calculator tool is widely used, with many individuals using the information to guide nitrogen applications at a time when fertilizer costs and corn prices are at record levels.  This timely information has helped producers maintain viable economic return from corn production.

100 Corn and Soybean Production


Page last updated: August 2, 2007
Page maintained by Linda Schultz,