Regional Nitrogen Rate Guidelines for Corn

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 publications and on-line web tools allows for a consistent resource, and readily provides access to new information.


The goal was to develop a regional approach to nitrogen rate guidelines for corn production and an on-line calculator tool for determining rate of N fertilization based on the regional approach and from recent nitrogen response databases and economic analysis.  The publication and web based tool are 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 developed in cooperation with soil fertility research and extension personnel from seven states in the U.S. Corn Belt.  Nitrogen rate guidelines presented in the publication are based on an economic analysis of recent nitrogen response databases provided by each state.  The goal was not to develop the same corn nitrogen rate guideline for the region, but rather to have a common approach to developing nitrogen rate guidelines.  The nitrogen rates suggested for a state are based on research conducted in that state, but the analysis and rate development approach is the same across the region.  An on-line web tool ( ) was developed that incorporated the 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 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 this reporting year, there have been approximately 17,660 visits to the site and 75,510 page views for 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 regional publication and web based calculator tool is widely used, with many individuals using the information to guide nitrogen applications at a time when fertilizer costs are at record levels.  This timely information has helped producers maintain viable economic return from corn production.

September 2006

103 Nutrient Management

Page last updated: September 13, 2006
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