Study: Sensors Outdo Farmers At Choosing Nitrogen Rates

Corn Field

Choosing how much nitrogen (N) to put on corn fields isn’t something farmers take lightly. Many factors go into the decision, including past experiences, the timing of application, yield goals, and results from soil tests.

Nevertheless, crop sensors can select N rates for corn that outperform those chosen by farmers, according to more than 50 on-farm demonstration projects conducted in Missouri from 2004 to 2008. Compared to producers’ N rates, sensor-selected rates increased yield by almost 2 bushels per acre, on average, while reducing by 25% the amount of excess N that was applied to fields but not removed in grain.

As concerns about N pollution continue to mount, the sensors offer a way to cut fertilizer inputs without hurting yield or profits. “The most important thing, I think, is that we were able to make progress on both fronts: The technology slightly improved production and slightly improved environmental outcome,” says the study’s leader, Peter Scharf, a University of Missouri extension agronomist. “There has been talk about win-win, but really there have not been a lot of approaches that have actually [achieved] that.”

Funded by the USDA-NRCS Conservation Innovation Grants program, the Missouri DNR Nonpoint Source Pollution Control program, and the U.S. EPA Special Grants program, the study appears in the November-December issue of Agronomy Journal.

Scharf explains that although optimal N rates can vary substantially within and between fields, most U.S. corn growers still apply the same rates to entire fields or even entire farms. Many farmers in Missouri and elsewhere also spread N fertilizer months before planting, often the November before.

As fertilizer and seed costs keep climbing, however, corn producers are feeling financial pressure to apply N more precisely — in amounts that satisfy crop requirements but don’t exceed them. To help farmers with this, in 1997 Scharf began studying methods for predicting where to put more N in fields and where to put less before sowing crops, since that’s the system most people use. But he and his colleagues eventually turned to crop sensors, employed after plants start growing, as a more accurate means to diagnose N deficiency and sufficiency.

The sensors take advantage of what farmers know already from experience and common sense, Scharf says: Crops with enough N are darker green and taller, while N-deficient crops are lighter and shorter. After developing a technique for translating sensor output into a suitable N rate within a few seconds — work that was published in 2009 — Scharf and his collaborators began taking the technology to farms.

Fifty five demonstrations were eventually conducted across a broad swath of Missouri’s corn-growing region. In most cases, two or three sensors were attached to N applicators already owned by farmers or their service providers, and then used to side-dress N at variable rates to corn in growth stages ranging from V6 and V16. At the same time, fixed N rates chosen by farmers were applied in other areas, allowing comparison of the two techniques.

An average of 14 pounds/acre less N was applied when sensors chose the rates, the researchers found, without affecting yields. In fact, during the exceptionally wet spring of 2008, sensor use actually boosted grain yield by 8 bushels/acre, on average, over what producer rates achieved–a significant bump that brought the overall yield gain with the sensors to 2 bushels/acre over all 55 fields.

Scharf believes yield increased significantly in 2008 because the sensors actually chose higher N rates than farmers did that year, better compensating for fertilizer lost through heavy rainfall. And this yield bump, coupled with an overall reduction in N fertilizer from 2004-2007, ended up increasing partial profit by an average of $17/acre across all farms.

Despite the sensors’ benefits, however, “the adoption numbers are still quite small,” Scharf says. Complete systems currently range in price from $10,500 to $16,500, and learning to use them involves time and expense, as well. Still, these aren’t the main hurdles to wider adoption, he adds.

The bigger one is getting farmers to side-dress N during the growing season, rather than fertilizing in spring before planting or even the fall before.

The unusually heavy rains of the past four years may change that. Because applying N months in advance gives it more time to leach and run off, many farmers have lost loads of it — and, therefore, money and yield — in recent rain-soaked years. That leaves one option: Applying the nutrient during the growing season.

“If this weather keeps up, I think we’ll see more people going toward in-season N application,” he says. “And that will be a big obstacle out of the way to using the sensors.”

Leave a Reply

Fertilizer Stories

Flooded corn in Indiana
FertilizerBoth Wet and Dry Conditions Threaten Nitrogen Loss
May 15, 2017
The weather is notoriously unpredictable, leading to challenges for planting, harvesting and applying the nitrogen (N) your corn crop needs. Read More
Iowa waterways
FertilizerDow AgroSciences Recognizes Ag Retailers’ Role in Protecting Iowa Water Quality
April 6, 2017
The state of Iowa and its agriculture community have worked for decades to preserve soil health, protect water quality and Read More
Yara West Sacramento Ribbon Cutting
Crop InputsYara West Sacramento Is Newest Addition
March 27, 2017
Yara’s West Sacramento Terminal was officially welcomed March 21 as the newest Yara North America facility in the U.S. While continually Read More
Nutrients for Life Foundation Teacher
FertilizerNutrients For Life Foundation Celebrates 10 Years Teaching Fertilizer Education
March 23, 2017
Those in agriculture know fertilizer is a vital ingredient to grow strong, productive crops. In fact, fertilizer is responsible for Read More
Trending Articles
Migrant farm workers
LegislationTrump: Immigration Crackdown Won’t Impact U.S. Agriculture
May 16, 2017
President Donald Trump said he would seek to keep his tough immigration enforcement policies from harming the U.S. farm industry Read More
AGCO Ratliff featured
Eric SfiligojRemembering Robert Ratliff
May 15, 2017
With all the fast-paced happenings in agriculture this spring, with multiple mergers in the works and planting season in full Read More
Case sprayer nozzle closeup
EquipmentSpray Application: A Nozzle Renaissance
May 2, 2017
If you had asked four-decade ag veteran Mark Bartel, President of Wilger Inc., just a few years ago what lay Read More
ManagementWashington Update, Dow-DuPont Earnings, and the Passing of an AGCO Legend
April 27, 2017
Editors Paul Schrimpf and Eric Sfiligoj talk about the latest Beltway news, crop protection company 1st quarter numbers, and the Read More
Crop InputsFlying Under the Radar No More, FMC Goes Big
April 13, 2017
Describing FMC as “under the radar,” admittedly, is probably a stretch. But in a snap of the fingers, FMC upped Read More
Young Corn Plants
Crop NutritionStill Hunting Yields
April 1, 2017
There’s no denying it — the agricultural marketplace today is undergoing a fundamental shift in fortunes. Not too many years Read More
Latest News
ManagementTrip Report, PSM R.I.P, and Ag’s Reaction to Federal Bu…
May 25, 2017
Editors Paul Schrimpf and Eric Sfiligoj talk about their recent travels, the end for Process Safety Management (PSM), and how Read More
Corn soil
LegislationARA Member Testifies Before Senate Ag Committee
May 25, 2017
Agricultural retailers stand on the front-lines of the American economy. As trusted advisors to America’s farmers, ag retailers are uniquely Read More
Young corn plants in soil
Crop InputsFortenza Insecticide Seed Treatment Receives EPA Regist…
May 25, 2017
Fortenza seed treatment insecticide from Syngenta has received registration approval from the U.S. EPA for use on corn and cotton Read More
ManagementFarm Market iD’s Agriculture Database Now Covers More T…
May 25, 2017
Farm Market iD, farmmarketid.com, has announced the release of its 2017 Annual Update of its farm and land database. The Read More
Food IT Fork-to-Farm
Precision AgThe Mixing Bowl Event Connects Technology, Food, and Ag…
May 24, 2017
For the fourth consecutive year, The Mixing Bowl presents FOOD IT, under the theme “Fork to Farm.” Action-oriented entrepreneurs, industry Read More
Photo credit: The United Soybean Board/The Soybean Checkoff.
Seed/BiotechKansas State University Researchers Find New Pathogens …
May 24, 2017
A single seed seems so simple. Put it in the ground, give it some care, and you’ve soon grown food. Read More
Soybean Field
HerbicidesNew Dicamba Herbicide Premix Coming Soon from Syngenta
May 24, 2017
Syngenta has announced the name of its new herbicide featuring the active ingredients of S-metolachlor and dicamba. Upon registration by Read More
Eric SfiligojMonsanto ‘Picks Its Battles’ by Nixing Deere Deal
May 23, 2017
Having been in the trade journalism game since the mid-1980s, I remember several watershed moments during my career. One of Read More
FungicidesSyngenta Launches New Seed Treatment Fungicide
May 22, 2017
Syngenta has announced the launch of PLENARIS seed treatment fungicide for the control of downy mildew in sunflower. PLENARIS contains Read More
Corn close up
Crop InputsMonsanto’s First HPPD Herbicide Garners EPA Appro…
May 19, 2017
Monsanto announced today that EPA has federally approved Harness MAX Herbicide, the first herbicide in the Monsanto portfolio to provide Read More
ManagementPrecision Planting Deal, China Developments, and Enviro…
May 18, 2017
Editors Eric Sfiligoj and Dan Jacobs discuss the latest news on John Deere’s now dead deal for Precision Planting, China’s Read More
Soybean aphid leaf
InsecticidesMulti-state Research Reveals IPM Best Option for Treatm…
May 17, 2017
About 89.5 million acres of soybeans will be planted across the U.S. in 2017 — a record high, according to Read More
GROWMARK-2017-Interns
CropLife 100GROWMARK Names 2017 Summer Interns
May 16, 2017
Forty-two college students are exploring agricultural career opportunities this summer as GROWMARK interns. They are working at FS member cooperatives Read More
Migrant farm workers
LegislationTrump: Immigration Crackdown Won’t Impact U.S. Ag…
May 16, 2017
President Donald Trump said he would seek to keep his tough immigration enforcement policies from harming the U.S. farm industry Read More
Flooded corn in Indiana
FertilizerBoth Wet and Dry Conditions Threaten Nitrogen Loss
May 15, 2017
The weather is notoriously unpredictable, leading to challenges for planting, harvesting and applying the nitrogen (N) your corn crop needs. Read More
farmer Kip Tom
Precision AgAg Tech: On the Cusp of Something Big?
May 15, 2017
The investment and ag-tech sectors’ continuing courtship of agriculture, smoldering for three or four years now, was well in evidence at Read More
AGCO Ratliff featured
Eric SfiligojRemembering Robert Ratliff
May 15, 2017
With all the fast-paced happenings in agriculture this spring, with multiple mergers in the works and planting season in full Read More
Greg Musson, Gar Tootelian
ManagementOpinion: Shaking Your Perspective in Ag Retail
May 12, 2017
Some of you I’m sure have encountered our recently retired salesman extraordinaire, Dan Bellanger. He worked in the industry for Read More