Wondering what in-season modeling tool to use - or one at all? NutrientStar can Help

Planting season is upon us, and as you consider the best ways to help farmers understand in-season nitrogen management, NutrientStar may have information you can use.

There are tools on the market that claim to deliver in-season nitrogen status information based on soils, weather and crop models. The Climate Corporation’s FieldviewTM Nitrogen Management Tool (NMT) and Yara US’ Adapt N (previously owned by Agronomic Technology Corporation) are two such models. But how well do they really work, and how might such tools fit into your business? NutrientStar has teamed up with Brookside consultants and other agronomists across the country to independently test these models and give you the facts about their performance. All the data are available on the NutrientStar website, along with a tool called the TEDs (Technology Extrapolation Domains) - which is a geo-spatial framework that helps interpret trial results.

For example, if you want to know how Climate FieldViewTM NMT performed in 2016 trials, you can visit the tool-finder page for the model and see a summary of results. When compared to the farmer’s normal treatment, the FieldViewTM NMT enabled an average decrease in the amount of nitrogen applied by 37 pounds, which resulted in slightly lower yields (4 bu/acre) but did not significantly impact the    average return on N fertilizer investment. More detailed results are available online, but to briefly summarize the data reveals that in 8 out of 34 trials, the response to N was below the lowest rate applied in the trial (between 0 - 100 lbs N/acre), and while the NMT in 6 of those trials recommended a much lower rate than the farmer would have applied, the NMT rate was still insufficiently low as well. In 18 of 34 trials, there was a response to N between 100 and 250#/acre, with the farmer return to N in 3 trials exceeding the NMT return to N by $10/acre or more, and the NMT return to N exceeding the farmer return to N by $10/acre in only one trial. In addition, in the remaining 8 of 34 trials, the response to N was not detected because the agronomic optimum rate exceeded the highest N rate in the trial of 250#/acre.

What is the take-away from these data? The advisor working with that farmer and that field may understand the dynamics driving the lack of response in certain fields, but these data offer an opportunity to start a dialogue about managing N application rates based on mineralization rate, leaching, denitrification potential and where poor soil quality may be limiting N uptake. The NutrientStar data collected by Brookside and other consultants goes beyond measuring model performance to tell this broader story that may help analyze field nutrient dynamics.

Now how do we track this locally/regionally?  We know that research is limited by funding, thus a limited number of plots are established each year.  Enter NutrientStar’s TED framework (and these are not TED talks for those wondering) that allow trial results to have applicability elsewhere even if trials were not conducted in your area. The TEDs (generated and field tested by researchers at the University of Nebraska) group regions with like climate and soils conditions together and assigns them a number. Each numbered TED reflects a range of values based on historic, actual weather data and soil conditioning data from the SSURGO database - for example, soil water storage capacity in millimeters and growing degree days are two such values. These are the factors influencing crop growth, and therefore could be considered much more relevant for viewing results of trials than state boundaries would be.

If, for example, you were an advisor in Hancock County Ohio and wanted to view trial results for a model such as Adapt N, you can enter your field boundaries into the TED tool to isolate the TEDs relevant to your farm or field. If you did so you might find that most of your farm falls in TED #504803. Looking at the table of TED characteristics tells you that TED #504803 contains over half a million corn acres, accounts for 6% of the corn growing area in the U.S., has soil water storage depth of 200 - 250 mm, and high temperature seasonality. The graphic below shows TED #504803 in blue and encompasses a wide geographic area (PA, OH, KY, IN, and IL).

Now we will find the Adapt N studies conducted in TED #504803 to see how the tool performed in agricultural fields experiencing similar climate and soils to your own. The table below shows average yields for trials from actual locations where Adapt N has been field tested. Note that yields in trials ranged significantly - from as high as 28 bu/acre to as low as -54 bu/acre. Average yield results across all trials in TED #504803 for Adapt N in 2015 - 2016 were -12 bu/acre compared to the farmer rate.

Adapt N 2015-2016 studies for corn in TED #504803

TED

Location name

Model

Study/Trial ID*

Trial year

Bu/ac difference

504803

Colfax, IL

Adapt-N

01-290

2015

-6.2

Cropsey, IL

Adapt-N

01-292

2015

-15.3

St Marys, OH

Adapt-N

04-002

2015

+5.3

Shelbyville, IN

Adapt-N

05-008

2015

-19.5

Franklin, IN

Adapt-N

05-009

2015

-9.8

Greenville, OH

Adapt-N

09-002

2015

-9.8

Farina, IL

Adapt-N

10-001

2015

-28

Farina, IL

Adapt-N

10-003

2015

-22

Belle Prairie City, IL

Adapt-N

10-004

2015

-1.3

Belle Rive, IL

Adapt-N

10-006

2015

-33.6

Sims, IL

Adapt-N

10-007

2015

-54

Sims, IL

Adapt-N

10-008

2015

-35.6

Edgewood, IL

Adapt-N

10-009

2015

9.1

Berne, IN

Adapt-N

15-001

2015

-3.5

Pontiac, IL

Adapt-N

01-293

2016

-36

Cooksville, IL

Adapt-N

01-294

2016

-14

Fort Wayne, IN

Adapt-N

03-008

2016

+.11

New Bremen, OH

Adapt-N

04-004

2016

+2.8

Wayne City, IL

Adapt-N

10-012

2016

-4.2

Farina, IL

Adapt-N

10-013

2016

+23.8

Buchanan, MI

Adapt-N

13-120

2016

-.03

Additional trial results for Adapt N are available at http://nutrientstar.org/tool-finder/adapt-n-research-findings/

This is just a small sample of the data available on the NutrientStar website. There are also data on performance of nitrogen stabilizers and enhanced efficiency fertilizers gleaned from a review of all trial data available in the literature.

If you would like a personalized tour of the NutrientStar data/website or assistance with navigating the TED tool, please contact the NutrientStar team as they are always available to assist.

John McGuire: mcguire9@gmail.com

Karen Chapman: kchapman@edf.org

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