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Make Smarter Split N Decisions With This New Online Tool

23:39PM Dec 09, 2014

The federally funded climate initiative “Useful to Useable” (U2U) continues to develop helpful decision-making tools for farmers. The latest is called “Corn Split N,” which can help farmers and farm advisers manage in-field nitrogen applications for maximized yields and minimized environmental impact.

Corn Split N is a free online tool for use in Iowa, Illinois, Indiana, Missouri and Kansas. It combines historical weather data and field conditions with economic considerations to determine the best dates and rates to make a post-plant nitrogen application in corn.

The tool was developed by U2U, which is a USDA National Institute for Food and Agriculture-funded initiative to improve the resilience and profitability of Corn Belt farmers in the wake of changing climate. The project team includes 50 faculty, staff and students from nine north-central universities, including the Corn Split N tool project coordinator, Chad Hart, Iowa State associate professor of economics.

"Traditionally, farmers have applied nitrogen to the soil in a single pass either in the fall or in the spring before planting," Hart says. "However, research has shown that by splitting the nitrogen over two intervals, applying it once in the fall or spring when the soil is not saturated and the temperature is between 50 and 32 degrees Fahrenheit, and then a second time when the plants are in the ground and in most need of it, will ultimately lead to better results. Less fertilizer will be needed overall and not as much will be lost in run off."

Hart says timing of N applications can vary greatly depending on weather and soil conditions. Corn Split N includes historical climate data to better pinpoint when nitrogen should be applied for the best results. A post-plant application needs to occur before the corn gets too tall, so the tool also factors in estimates of development stages based on location, selected planting date and accumulated growing degree days.

Users can see customized results based on their planting and fertilization schedule, plus local costs and available equipment. A fieldwork table and crop calendar also allow farmers to see how schedule adjustments could affect their ability to fertilize on time.

Corn Split N will expand to Wisconsin, Minnesota, South Dakota, North Dakota, Nebraska, Ohio and Michigan for 2015. For more information, visit or the U2U homepage,