Better Manage Nitrogen With Software

Why is managing nitrogen so challenging?

"Because it's arguably the most important decision when growing a corn crop," says Matt Waits, CEO of SST Software. "Yet, there are so many uncontrollable factors to deal with that nitrogen management quickly becomes a very emotional decision. This results in most growers hedging to the side of overapplication to ensure desired yields."

While common sense may tell you that if your goal is maximum yield, and there's a decent margin to cover that bet, then nitrogen should be unlimited.

"Unfortunately, when nitrogen is applied at rates above crop demand, it is easily lost to the environment, potentially causing issues," says Brian Arnall, associate professor, Oklahoma State University. "Yet, recommending less nitrogen than traditionally applied can create a fear of loss or a feeling of being at risk."

When margins are tight, the grower may take the opposite stance. "If he is told to apply more, it is hard for him to see the economic value," he says.

In reality, the actual need for nitrogen, he says, is guided by a major factor that is out of the farmer's control – weather. "Nitrogen in the soil is driven by organic matter and the amount of nitrogen released by or tied up by organic matter," Arnall explains. "Both are driven by weather. It can increase the amount of nitrogen lost via leaching and denitrification. Weather can also impact how well nitrogen is used."

Rate, source, method, timing, and placement also impact its efficiency. "All of these factors play into a grower needing to apply anywhere between 0.5 to 1.5 pounds of nitrogen per bushel of corn from season to season and across a landscape," he says.

Based on Science

To minimize risk of yield loss for corn, companies like Indiana-based ForeFront Ag Solutions are deploying tools like Adapt-N to help growers benchmark and track nitrogen applications throughout the growing season. Developed by Cornell University and offered through Agronomic Technology Corporation, Adapt-N is an independent cloud-based software program that is scientifically driven to calculate the nitrogen needs of corn at sidedress time.

"Adapt-N considers 15-plus factors in the algorithm," says Erich Eller, ForeFront Ag Solutions.

Based on various inputs the user can provide, the model performs thousands of simulations when making a recommendation. It takes into account management practices, key information about the field's soils using data from systems like SST, as well as real-time and historical weather data. It then prescribes a flat or variable-rate prescription based on user preference. When using the variable-rate recommendation, Eller says every field is a trial.

"We are able to track, by management zone, the amount applied and the return on investment vs. yield," he says. "We identify management zones because each zone has a different ability to utilize nitrogen and produce bushels. Typically, the return on investment of variable rate compared with a straight rate of nitrogen is a $20- to $30-per-acre advantage."

Some fields show an even greater return. For example, he ran a trial where 99 pounds of nitrogen outyielded 200 pounds of nitrogen by 4 bushels. "Each trial was replicated across a field adding up to about 20 acres per rate," Eller says. "It was about a $50-per-acre savings."

"We can't say Adapt-N recommends more or less nitrogen, as this varies field by field and season by season," says Greg Levow, Agronomic Technology Corporation president and chief operating officer. "We can say it helps a farmer apply nitrogen where it's needed, when it's needed, even down to a 60×60-foot spot in the field."

Get Ahead of Regulations

Tools like Adapt-N are providing valuable information about nitrogen losses and plant uptake, says Arnall.

"This is allowing producers to refine their nitrogen rate recommendations beyond yield goals and management zones based upon past harvest," he says.

"It is allowing us the ability to apply the right rate at the right time," says Eller. "This decreases the chances of overapplying, which leads to improved return on investment and less impact on the environment."

"Regulations could some day set hard limits on nitrogen application rates without taking into account variations in fields, practices, and weather, which inherently cause different rates to be needed in different circumstances," says Levow. "Adoption of Adapt-N can help farmers get ahead of regulations. It can demonstrate they are farming responsibly and that such regulations would be detrimental and unnecessary."

Cornell University researchers recommend these five tips to ensure you get the most accurate Adapt-N recommendations.

1. Use accurate data. To estimate expected yield, use three to five years of accurate yield info.
2. Manage manure better. Reduce the margin of error associated with manure applications by using representative manure test results from actual manure inputs.
3. Define the management unit. Up to three zone-creation modes are possible in Adapt-N: point-based, polygon-based variable rate, and gridded (60×60 feet) variable rate. These can be defined by several user inputs of spatial data including soil type, historical yield data, and organic matter content.
4. Sample soil at appropriate depth, location, and time. Account for field variability and nutrient availability in space and time. Samples should be taken at least at a 6-inch depth, every three years, from uniform zone or grid-based areas.
5. Coordinate software, application. If possible, run Adapt-N on the date of sidedress. "By basing recommendations closest to that date, local weather conditions are accounted for. Thus, the tool improves nitrogen-use efficiency," says Aaron Ristow, Cornell University Extension associate.

In addition, use the daily alert feature to automatically receive updated recommendations on all fields.

Research Findings

In a four-year study (2011 to 2014) conducted by Cornell University, researchers explored the economic and environmental benefits of Adapt-N.

"In 113 trials conducted in New York and Iowa, we found win-win opportunities for both producers and the environment," says Aaron Ristow, Extension associate, Cornell University.

In 83% of the trials, Adapt-N recommended a lower nitrogen application than the respective grower rate with a 40-pound-peracre (34%) average reduction. At the same time, the average profit increased by $26 per acre.

"In terms of environmental losses, we found an average reduction of 36% in simulated leaching losses and a 39% reduction in gaseous losses to the atmosphere," he says. "Overall, adoption of a tool like Adapt-N can contribute to efforts to reduce the environmental costs of nitrogen fertilization while increasing the economic benefits to growers."

Adapt-N also includes N-Insight, which is designed to assess the financial and environmental impact of nitrogen. This software is targeted to ag service providers so they can quickly evaluate the value of using precision nitrogen-management tools.

"N-Insight was built on the same modeling components as Adapt-N and is a conversation starter between growers and agronomists. It helps growers understand how to adapt to in-season weather conditions, how soil conditions impact N loss, and how changes in management practice may improve yield and environmental performance," explains Ristow.

A cloud-based platform, Adapt-N is highly scalable and ready for rapid adoption, Ristow adds. It's available in 38 states.