Field Crop Sensors Determine In-Season Fertilization

Growers on the northern Plains continue to adopt precision agriculture technology and management practices.

In-field crop sensors are one of the new technologies farmers are using to help manage nitrogen fertilizer applications, particularly in corn and wheat. In-field sensors are used to apply variable rates of fertilizer across fields to maximize yields.

“This technology has the potential to increase yields by increasing nitrogen efficiency and, at the same time, protecting the environment,” says John Nowatzki, North Dakota State University Extension Service agricultural machine systems specialist. “For example, variable-rate fertilization gives farmers the option of decreasing nitrogen applications in areas with shallow aquifers, which reduces the potential for water contamination from nitrogen leaching.”

Crop sensors are mounted directly on the fertilizer application equipment and then coupled with variable-rate controllers. This allows farmers to vary fertilizer application rates to growing crops. Applying fertilizer to growing crops allows farmers to make split applications.

“In many cases, producers apply two-thirds of the recommended nitrogen fertilizer at or prior to planting and then apply the remainder as needed during the growing season,” Nowatzki says. “Farmers also can use in-field sensors to accurately estimate crop yield and get information they can use to make management decisions, such as whether or not to apply fungicides or insecticides. Crop sensors simplify the remote sensing process by transferring data directly to the computer on the tractor or fertilizer applicator in real time.”

Crop sensors function by measuring the amount of light waves that are absorbed and reflected by the plant leaves. The sensors estimate plant health and vigor by focusing light on plants and then comparing the amount of specific light waves that are absorbed by the leaves with other light waves that are reflected off the leaves.

The resulting comparisons are referred to as vegetative indices. The normalized difference vegetative index (NDVI) is the index most commonly used in remote sensing of agricultural crops. The NDVI compares the amount of red light absorbed by plants with the amount of near infrared light reflected off plants. Healthy green leaves absorb more red light than leaves that are lighter green.

Commercial in-field crop sensors use different methods to determine how much nitrogen fertilizer to apply in each area of a field. Some systems require farmers to apply ample fertilizer on a test strip in a field, which often is called a nitrogen-rich strip. The operator then drives over that area so the computer controller in the tractor can compare each area of the field with the nitrogen-rich strip.

Other systems recommend operating the sensors over representative areas of each field and making the rate decision based on average sensor readings.

Commercially available in-field sensors include Ag Leader’s OptRx, Topcon’s CropSpec, Trimble’s GreenSeeker and Holland Scientific’s Crop Circle. Each company has unique sensors, mounting techniques and methods of determining plant nutrient requirements. Current crop sensors focus on crop nitrogen needs.

Some companies recommend using one sensor for each 10-foot section of application width and mounting the sensors on the applicator booms, while others use only two sensors mounted on top of the tractor cab. The cost of each system ranges from $10,000 to $20,000.

“The results of in-field sensor research generally indicate that crop producers will use less nitrogen fertilizer to reach their goals,” Nowatzki says. “Farmers also can use this technology to advance management practices designed to maximize yields. In-field sensing technology complements in-season fertilization practices by allowing farmers to more accurately apply only the needed amount of fertilizer at each field location.”

Three NDSU Research Extension Centers are including in-field crop sensor presentations in their field day tours this summer. Nowatzki presented information on in-field sensor technology at the Hettinger REC field tour on July 10. Walt Albus, NDSU research agronomist at the Oakes Irrigation Research Site, will present similar information at the NDSU Agronomy Seed Farm field tour on July 16 and at the Williston REC field tour on July 24.

Leave a Reply

Precision Ag Stories

Corn Field
FertilizerBridging Crop Nutrition Science And Technology
September 7, 2016
The future seemed to draw nearer for the 1,600-plus attendees of the co-located InfoAg and International Precision Agriculture conferences in St. Read More
Deere R4023 cab
Precision AgPrecision Ag Aids Fertilizer Programs
September 6, 2016
Whatever the farm economy may look like, retailers need to continue to develop a sound fertility program to reach the Read More
EquipmentCase IH Debuts Nutri-Tiller 955 Strip-Till Applicator
August 24, 2016
With strip-till continuing to expand across new acres, Case IH designed the new Nutri-Tiller 955 strip-till applicator to help producers Read More
EquipmentCase Launches Aim Command FLEX, 25th Anniversary Patriot Sprayer
August 24, 2016
Case IH announces new AIM Command FLEX advanced spray technology for greater application accuracy, as well as special 25th Anniversary Read More
Trending Articles
Matt Hopkins15 Twitter Accounts Every Ag Professional Must Follow
October 13, 2016
What do singer Katy Perry and the President of the United States have in common? They are two of the Read More
AGCO RG700 cab
OpinionRoadblocks To Precision Ag Innovation
October 5, 2016
On August 29, I got to preside over the PrecisionAg Innovation Series event, “Game-Changing Advances in Precision Farming Technology,” developed Read More
J.C. Ramsdell containment system
EquipmentClear Opportunity In The Tank Market
October 4, 2016
Crop prices may be down, but steel prices are too — and that’s good news for retailers looking to add some Read More
WinField booth Farm Progress
Special ReportsTalking Weed Management Strategies At Farm Progress 2016
October 2, 2016
The annual Farm Progress Show — this year staged in Boone, IA — is always a great place to catch Read More
Corn Field
Eric SfiligojFacing Ag Industry Challenges
September 26, 2016
At the 2016 annual Mid America CropLife Association (MACA) meeting in September, a pair of crop protection company representatives discussed Read More
Bayer Monsanto
Crop InputsBayer-Monsanto Mega-Merger: 6 Things You Need To Know
September 14, 2016
Mega mergers have become almost routine in the agricultural industry. Right on the heels of Monday’s news that fertilizer giants Potash Read More
Latest News
AGCO RG700 at the 2015 National Farm Machinery Show
EquipmentAGCO Parts Rolls Out No-Interest, No-Payments Offer Via…
October 26, 2016
AGCO Corp. is now offering an innovative financing solution on qualifying Parts and Service transactions. Now through December 31, 2016, Read More
Soybean field
Crop InputsIncotec Invests In North America
October 25, 2016
Leading seed enhancement company Incotec, part of Croda, has announced an investment in their North America business. The total investment of Read More
Patriot 25th anniversary
SprayersCase IH Celebrates 25 Years Of Patriot Sprayers At Bens…
October 24, 2016
Case IH executives, employees and special guests celebrated 25 years of production of Case IH Patriot sprayers in a special Read More
4r Nutrient stewardship
StewardshipNominations For The 4R Advocate Program Due October 31
October 24, 2016
Nominations for the 4R Advocate program are due to The Fertilizer Institute by October 31, 2016. The program recognizes agricultural Read More
Corn close up
Eric SfiligojProtecting Agriculture’s Ability To Feed The World
October 24, 2016
The rate of change coming to agriculture is growing, and will continue to do so for the foreseeable future. This Read More
Student Young Worker CHS
CropLife 100CHS Supports #FirstJob Compact
October 24, 2016
CHS joins the White House and many of the country’s largest employers in signing a new initiative centered on helping Read More
Kennebec Grain terminal
CropLife 100Wheat Growers Kennebec Facility Loads First Rail Cars
October 21, 2016
In a season of firsts for Wheat Growers’ Kennebec Grain Terminal, the first 115-car unit train was loaded with soybeans Read More
ManagementThe Latest Dow-DuPont Rumor, Product of the Year Voting…
October 20, 2016
CropLife Editor Eric Sfiligoj shares a new rumor about the Dow-DuPont merger and updates on two CropLife-driven programs, the CropLife Read More
Soybean Closeup
FungicidesFMC Begins Registration Process For New Fungicide Activ…
October 19, 2016
FMC Agricultural Solutions has begun the joint U.S. EPA and Canadian Pest Management Regulatory Agency registration process for bixafen, a new Read More
Soil Young Corn
Industry NewsAgribusiness Search Firm Appoints New Managing Partner
October 18, 2016
Morris Bixby Group, a leading agribusiness search firm providing the highest quality professional recruiting and career advancement services since 2000, Read More
Wheat Field North Dakota
FertilizerUnited Suppliers Acquires Kansas Fertilizer Business
October 17, 2016
United Suppliers, Inc. has purchased the assets of Evans Enterprises, LLC, an ammonium chloride fertilizer business based in Olathe, KS. Read More
Corn Field
Industry NewsFMC Launches New Operations In Argentina, Exits Joint V…
October 17, 2016
FMC Corp. has exited its joint venture with Ruralco Soluciones S.A. FMC has launched new commercial operations, FMC Quimica S.A., Read More
Dow AgroSciences
InsecticidesRenewed Registration Issued For Products Containing Sul…
October 17, 2016
On October 14, 2016, the U.S. EPA re-established the registration of products containing sulfoxaflor (Isoclast Active), including Transform WG, Closer Read More
Eric SfiligojThe Whys Of Agriculture
October 17, 2016
During 2016, there have been myriad challenges facing the whole agricultural industry. Such wide ranging issues as water protection, sustainable Read More
Young Corn Field
FertilizerImproved Phosphorus Management Essential To Feeding Wor…
October 14, 2016
With a global population expected to reach 9 billion people by 2050, improved management of key essential nutrients such as Read More
ManagementHarvest and Crop Price Updates; EPA and Crop Protection…
October 13, 2016
Glyphosate and atrazine get public comment support from ARA as each is reviewed by EPA, and the latest on the Read More
Matt Hopkins15 Twitter Accounts Every Ag Professional Must Follow
October 13, 2016
What do singer Katy Perry and the President of the United States have in common? They are two of the Read More
Corn Field
Industry NewsArysta LifeScience Adds Two Key Account Managers
October 13, 2016
Arysta LifeScience North America recently announced the addition of two key account managers: Doug Hoberty and Rob Wier. Hoberty and Read More