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

FertilizerFall Fertility 2014: Forecasting Fertilizer Use
September 7, 2014
Great crops this year have tapped the soil, and fall work is definitely called for, but how challenging will that get? Read More
Aerial view of the West Fertilizer explosion site
FertilizerFertilizer Companies Blame City For West, TX, Explosion
August 6, 2014
El Dorado Chemical Co. and CF Industries contend the city failed to properly train the first responders and had insufficient protocols in place to battle the April 17, 2013, blaze at West Fertilizer Co. that triggered the explosion. Read More
FertilizerThe Fertilizer Institute: New President, Renewed Energy
February 3, 2014
Chris Jahn relishes the opportunity to lead the organization through the challenging times ahead. Read More
FertilizerA New Cycle For Fertilizer Demand
January 2, 2014
Changes in the corn market could have a major impact on the crop nutrients sector in 2014, say experts. Read More

Trending Articles

Crop InputsPlatform Specialty Products To Acquire Arysta LifeScience
October 20, 2014
Once the acquisition is complete, Platform Specialty Products will combine Arysta LifeScience with previously acquired companies Agriphar and Chemtura Crop Solutions. Read More
Seed/BiotechMonsanto Offers New Support For Ferguson, Area Communities
October 8, 2014
Monsanto Co. has committed $1 million in new support for several collaborative efforts in Ferguson, MO, and surrounding communities in North St. Louis County. Read More
Seed/BiotechUnapproved Genetically Modified Wheat Found In Montana
October 3, 2014
USDA reports that one year after discovery of Monsanto's unapproved wheat in a single Oregon field disrupted U.S. wheat export sales, the GMO wheat has again been found in Montana. Read More
Equipment2014 Product Of The Year Voting
September 19, 2014
The deadline to vote for the 2014 CropLife IRON Product of the Year is October 31. Please cast your vote today to help us determine the winner. Read More
FertilizerFall Fertility 2014: Forecasting Fertilizer Use
September 7, 2014
Great crops this year have tapped the soil, and fall work is definitely called for, but how challenging will that get? Read More
CropLife 100CHS To Build $3 Billion Fertilizer Plant In North Dakota
September 5, 2014
The fertilizer plant in Spiritwood will be the single largest investment in CHS history, as well as the single largest private investment project ever undertaken in North Dakota. Read More

Latest News

Seed/BiotechMonsanto Named One Of The World’s Best Multinational …
October 23, 2014
Monsanto ranked No. 8 in the world’s largest annual study of workplace excellence that identifies the top 25 best multinational companies in terms of workplace culture. Read More
Crop InputsArysta Hires Former Agri-Chem, CPS Employee For Delta S…
October 23, 2014
New Territory Sales Manager Mark Peel’s primary role will focus on working with growers regarding fungicides in Louisiana, Mississippi, Arkansas and Tennessee. Read More
CropLife 100GROWMARK Announces Appointments In Plant Food Division
October 22, 2014
GROWMARK, Inc. has announced the three key staff changes in its Plant Food Division. Read More
CropLife 100GROWMARK Appoints New VP Of Finance And Risk Management
October 22, 2014
Wade Mittelstadt has been named GROWMARK Vice President, Financial and Risk Mangement, effective December 1, 2014. Read More
FungicidesEPA Approves BASF In-Furrow Corn Fungicide
October 22, 2014
Field trials show Xanthion In-furrow fungicide provides more rapid emergence, extended residual control and improved seedling health than untreated crops. Read More
EquipmentAgraScout App Available At No Cost To Universities
October 21, 2014
AgraScout, a fast and easy to use mobile crop scouting app, is now available at no cost to University students, Read More
LegislationNew Farm Bill Program To Provide Relief To Farmers Affe…
October 21, 2014
The USDA has implemented a new Farm Bill initiative that will provide relief to farmers affected by severe weather, including drought. Read More
ManagementGreenfield Scholars Program Aims To Sustain Agronomy Wo…
October 21, 2014
The program encourages talented students to study agronomy, crop and soil sciences while cultivating networks to develop the necessary workforce to sustain the profession. Read More
Paul SchrimpfPrecision Ag: Taking It To The Hill
October 21, 2014
A new coalition took the good news message of precision agriculture to Washington, DC, last month. Read More
ManagementUSDA Awards $18 Million In Small Business Research Gran…
October 21, 2014
The grants will provide high quality, advanced research and development that will lead to technological innovations and solutions for American agriculture. Read More
FertilizerCF Industries Terminates Merger Discussions With Yara I…
October 21, 2014
CF Industries Holdings and Yara International have terminated their discussions regarding a potential merger of equals transaction. Read More
Seed/BiotechSyngenta Ranked A Top 10 Biotech Employer For Third tim…
October 20, 2014
Syngenta ranked in the top 10 among the world’s top biotech employers, according to an annual survey conducted by Science magazine. Read More
CropLife 100Wheat Growers Break Ground For New Facility At Kennebec
October 20, 2014
Wheat Growers has broke ground for a state-of-the-art shuttle loader grain handling, fertilizer and agronomy facility in Kennebec, SD. Read More
FertilizerVerdesian Life Sciences Signs Agreement With Los Alamos…
October 20, 2014
Verdesian Life Sciences has signed a licensing agreement with Los Alamos National Laboratory to develop and market LANL’s latest nitrogen enhancement technology for plants. Read More
MicronutrientsStoller Group Announces Groundbreaking At New Office Bu…
October 20, 2014
Jerry Stoller, founder and president of Stoller Group, announced the groundbreaking at the site of the company’s future headquarters in Read More
Crop InputsBioSafe Systems Opens New Production Facility In Nevada
October 20, 2014
BioSafe Systems has completed construction of a state-of-art production facility in Sparks, NV, for its line of activated peroxygen products. Read More
Crop InputsPlatform Specialty Products To Acquire Arysta LifeScien…
October 20, 2014
Once the acquisition is complete, Platform Specialty Products will combine Arysta LifeScience with previously acquired companies Agriphar and Chemtura Crop Solutions. Read More
Seed/BiotechEPA Approves Dow’s Enlist Duo Herbicide
October 15, 2014
The Enlist Weed Control System, breakthrough technology to fight resistant and tough weeds, has received the long-awaited green light from federal regulatory authorities. Read More