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

Mike Stern
Precision AgClimate Corp. CEO Talks Retailer Support For Digital Ag
December 1, 2016
CropLife Magazine’s sister publication, AgriBusiness Global, recently sat down with Mike Stern, CEO of The Climate Corp., following the Monsanto subsidiary’s Read More
Precision AgTrimble Debuts End-to-End FMIS Platform
November 28, 2016
October’s inaugural PrecisionAg Vision Conference left this author with many thoughts and things to ponder in the coming months. Probably Read More
AGCO AgControl system
Precision AgPrecision Ag Technology: Rate Control For The Times
November 28, 2016
It’s not surprising that the need for more economical, effective application is driving the demand for the latest rate controllers Read More
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
Trending Articles
R4023 Sprayer, John Deere
CropLife 100Ag Retail Equipment Report: The Green Party Continues
December 7, 2016
In the annual race for sales in the ag retail equipment marketplace, the color schemes for participants are a little Read More
Mike Stern
Precision AgClimate Corp. CEO Talks Retailer Support For Digital Ag
December 1, 2016
CropLife Magazine’s sister publication, AgriBusiness Global, recently sat down with Mike Stern, CEO of The Climate Corp., following the Monsanto subsidiary’s Read More
Precision AgTrimble Debuts End-to-End FMIS Platform
November 28, 2016
October’s inaugural PrecisionAg Vision Conference left this author with many thoughts and things to ponder in the coming months. Probably Read More
CHS Primeland
CropLife 100The 2016 CropLife 100 Report: Reviewing The Many Bulls And Bears Impacting This Year’s Marketplace
November 28, 2016
For virtually all of 2016, the nation was wholly focused on the big Presidential election. Some folks aligned themselves with Read More
Monsanto sign
Crop InputsMissouri Governor Meets With Bayer CEO To Discuss Monsanto Merger
November 21, 2016
Missouri Gov. Jay Nixon visited Bayer AG global headquarters in Leverkusen, Germany, on November 18 to discuss the proposed Bayer-Monsanto Read More
STS16 2017
SprayersHagie Manufacturing Releases 2017 STS16 Sprayer To Market
November 16, 2016
Hagie Manufacturing LLC’s largest full season applicator is now available with enhancements for the 2017 model year. Hagie is officially Read More
Latest News
ManagementARA 2016 Report and Crop Mix for 2017
December 9, 2016
Editors Paul Schrimpf and Eric Sfiligoj talk about the recent Agricultural Retailers Association meeting and the projected acreage mix for Read More
AgriSync
Matt Hopkins17 Agriculture Apps That Will Help You Farm Smarter In …
December 9, 2016
Ag professionals are working smarter, not harder, than ever before. Smart farming technologies have enabled them to reduce costs, maximize Read More
Ryan Bartlett
Crop InputsCompass Minerals Appoints Vice President, Innovation An…
December 8, 2016
Ryan Bartlett, Ph.D., has joined Compass Minerals as vice president, innovation and product development. Dr. Bartlett will be responsible for Read More
HerbicidesHerbicides 2017: New Cropping Systems Set For Debut
December 7, 2016
Herbicide-resistant weed are inching ever-closer to a potentially frightening saturation point here in the U.S. Heading into 2016, USDA planting Read More
CropLife 100Wilbur-Ellis Acquires Michigan Ag Retailer
December 7, 2016
Wilbur-Ellis’ Agribusiness, a recognized leader in precision agriculture technology and the distribution and marketing of plant protection, seed and nutritional Read More
Fertilizer storage The Andersons
CropLife 1002016 Fertilizer Report: Another Really Rough Year For A…
December 7, 2016
In many ways, the fertilizer category cannot seem to catch a break. During the early part of the 2010s decade, Read More
R4023 Sprayer, John Deere
CropLife 100Ag Retail Equipment Report: The Green Party Continues
December 7, 2016
In the annual race for sales in the ag retail equipment marketplace, the color schemes for participants are a little Read More
Winter wheat
HerbicidesTalinor Herbicide Approved For Wheat And Barley
December 7, 2016
Talinor herbicide from Syngenta has received federal registration from the U.S. EPA, giving wheat and barley growers a new option Read More
Forage Sorghum
UncategorizedMilestone Achievement Continues For Dow AgroSciences, A…
December 7, 2016
New and innovative forage products are on the horizon driven by continued collaboration between Dow AgroSciences, a wholly owned subsidiary Read More
Palmer pigweed seedhead in cotton
HerbicidesNew WSSA Factsheet Explores Weed Seeds And Their Longev…
December 7, 2016
Did you know some weed seeds can lie dormant in the soil for more than a century and then sprout Read More
Crop InputsARA 2016: 5 Developments Worth Monitoring Into 2017
December 6, 2016
You can pretty much set your watch to it (do people even still wear watches? I know I do…but I’m Read More
Tim McCardle, ARA Chairman
CropLife 100BRANDT COO Named ARA Chairman
December 5, 2016
BRANDT EVP and Chief Operating Officer Tim McArdle has been named chairman of the Agricultural Retailers Association (ARA) during a Read More
Crop InputsWilbur-Ellis Receives ResponsibleAg Certification At Mo…
December 5, 2016
Wilbur-Ellis Co., a recognized leader in precision agriculture technology and the distribution of crop protection products, announces the ResponsibleAg certification Read More
Young Corn Closeup
Eric SfiligojThe Read On 2017 For Agricultural Fortunes Is Anybody’s…
December 5, 2016
As I (and others) have written in recent months, the nation has just experienced one of the most offbeat election Read More
Acceleron B-300 seed coating
Crop InputsThe BioAg Alliance Launches New Yield-Boosting Microbia…
December 5, 2016
As part of their commitment to develop and commercialize innovative microbial solutions for farmers through The BioAg Alliance, Monsanto Co. Read More
ManagementCorn and soy planting update; Takeaways from Climate Co…
December 2, 2016
AgriBusiness Global Editor Dave Frabotta Joins Paul Schrimpf for a discussion of global corn and soybean planting trends, and a Read More
Radish cover crop taproot
Crop InputsSoil Health Institute, Datu Research Receive Grant To E…
December 1, 2016
The Soil Health Institute (SHI) and Datu Research have announced a $626,000 grant from the Walton Family Foundation to quantify the Read More
Mike Stern
Precision AgClimate Corp. CEO Talks Retailer Support For Digital Ag
December 1, 2016
CropLife Magazine’s sister publication, AgriBusiness Global, recently sat down with Mike Stern, CEO of The Climate Corp., following the Monsanto subsidiary’s Read More