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

Precision AgGoogle Glass: New Tool For Ag
October 8, 2014
New wearable smart technologies such as Google Glass show potential to greatly impact how we accomplish the business of feeding the world. Read More
Precision AgPrecision Agriculture: Finding The Payback
September 6, 2014
Profitability in precision ag is not about any one technology, but the result of employing technology in a total system approach that is agronomically sound. Read More
Precision AgUAS: The S Stands For Smart, Service And Sensors
May 1, 2014
The only thing occuring more rapidly than the technologies’ evolution is the clamoring to implement UAS into agriculture as soon as possible. Read More
Precision AgAg Retail: 3 Tech Trends To Watch In 2014
April 1, 2014
It's been a busy first quarter of technology developments in 2014. Here are some of the highlights, and things to watch in the months ahead. 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

StewardshipResponsibleAg Begins Auditor Training
October 31, 2014
ResponsibleAg auditor training is now underway at the Ford B. West Center for Responsible Agriculture in Owensboro, KY. Read More
CropLife 100ValueAct Buys Stake In Fertilizer Dealer Agrium
October 30, 2014
ValueAct has bought 8.2 million shares in Calgary, Alberta-based Agrium, making them the second largest investor in the fertilizer dealer. Read More
InsecticidesNew Research Study Shows The Value Of Neonics
October 29, 2014
The study evaluated seed treatment, soil and foliar uses of neonicotinoid insecticides in the U.S. and Canada. Read More
StewardshipUSDA To Provide $4 Million For Honey Bee Habitat
October 29, 2014
Agriculture Secretary Tom Vilsack announced today that more than $4 million in technical and financial assistance will be provided to Read More
Crop InputsValent Launches New Low VOC ProGibb LV Plus Plant Growt…
October 29, 2014
ProGibb LV Plus PGR is a high-potency, liquid gibberellic acid formulation designed to comply with California’s new air quality standards for high volatile organic compound agricultural products. Read More
Crop InputsBayer CropScience Acquires Certain DuPont Crop Protecti…
October 29, 2014
Bayer CropScience and DuPont Crop Protection have signed an agreement for Bayer to purchase certain DuPont Crop Protection Land Management assets in the U.S., Canada, Mexico, Australia and New Zealand. Read More
ManagementWest Central Names New President
October 29, 2014
West Central’s board of directors have announced their unanimous decision to name Milan Kucerak President and CEO-elect following Jeff Stroburg’s retirement at the end of the fiscal year. Read More
InsecticidesValent U.S.A., MGK Form Marketing Agreement
October 24, 2014
Valent has formed an agreement with Minneapolis-based MGK to manage the marketing and sales of MGK’s crop protection line of insect control products within the U.S. beginning April 1, 2015. Read More
StewardshipFlorida’s 4R Advocate Keeps Improving
October 24, 2014
Florida farmer Alan Jones uses the 4R principles of nutrient stewardship as the core of his fertility program, which allows him to maximize production and keep costs in check. Read More
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