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Nitrogen Balance: A new tool for evaluating nitrogen management

Article cover photo
A tool being used by ISA regional agronomists can help farmers see how well their nitrogen management performed at the end of the crop year. Results can help make adjustments for the following season. (Photo: Joseph L. Murphy/Iowa Soybean Association)

By Scott Nelson, ISA On-Farm Network® Director 

Iowa farmers have a new resource to help them refine their nitrogen management. The Nitrogen Balance tool, developed for the Iowa Soybean Association by MyFarms, can analyze the difference between nitrogen inputs, like fertilizer or manure, and nitrogen outputs, such as nitrogen lost to the environment or grain leaving the farm. The tool creates an easy-to-understand scorecard on how well nitrogen was managed, enabling farmers to make profitable refinements for next year’s production.

An example scorecard is shown in Figure 1. In this example, the farmer is comparing results from five fields. Optimum nitrogen balance levels should fall between the two vertical yellow lines. In field B71 there was an excessive nitrogen balance, showing excess nitrogen being lost to crop production. Fields 3J7, 3J2 and 97E all had acceptable nitrogen balance, meaning these fields were managed successfully for nitrogen utilization. The field at the bottom of Figure 1 shows an insufficient nitrogen balance, where there was not enough nitrogen to optimize corn yield.

Figure 1: Nitrogen Balance comparison between five fields. The red bars indicate either a shortage or an excess of nitrogen in a field. The green bars indicate a positive balance.

The Nitrogen Balance tool allows farmers to view anonymous aggregated data, as shown in Figure 2. In this graph, farmers in a region have input their data, which has been aggregated in the chart. This will help to understand the effects of nitrogen application timing on nitrogen balance in the area with similar soils and weather events. 

Note that split applications generally had lower nitrogen loss. In other words, split applications lost less nitrogen and were generally more profitable when compared to fall applied nitrogen, which had the highest amounts of nitrogen loss.

Figure 2. Nitrogen balance comparison between split nitrogen application to spring and fall applied nitrogen.

The Nitrogen Balance tool is available only through ISA regional agronomists. Farmers who are interested in receiving nitrogen balance information for their farms should contact their ISA regional agronomist or email:

To complete the Nitrogen Balance formula, the agronomist will need fertilizer practices and yield monitor data for the particular crop. The Nitrogen Balance tool will analyze this data along with weather events to create a report. Data will be kept private and anonymous.

While nitrogen balance is an Iowa Soybean Association research project, funding for this research was from non-checkoff dollars.

Contact Scott Nelson at


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