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 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
Valley Variable Rate Irrigation
Precision AgMaximizing Returns From Water Inputs
March 3, 2014
Irrigation manufacturers have developed some vital new technologies to fine-tune irrigation and save growers money, water, energy and labor. Read More
Todd Golly and UAVs
Precision AgReal-World UAV Experience In Agriculture
February 3, 2014
Minnesota grower Todd Golly shares his views on the use of unmanned aerial vehicles. Read More

Trending Articles

Green Valley Ag facility
Retail FacilitiesGreen Valley Ag Adopts A.J. Sackett’s Precision Fertilizer Blending® Technology At New Facility
July 8, 2014
Sackett's Precision Fertilizer Blending® Technology is making huge strides around the world. Green Valley Ag adopts the technology at its new facility to support its advancing agronomic needs. Read More
Retail FacilitiesWaconia Manufacturing Builds Facility Designed For Speed, Efficiency
July 7, 2014
To make its new hub facility more efficient, Cooperative Elevator enlisted the aid of Waconia Manufacturing. Read More
EquipmentSummer Show Preview 2014: Superior Sprayers Take The Field
July 3, 2014
In this final installment of our coverage of the major categories of Big IRON that retailers can expect to test-drive at this summer’s events, here is a look at 19 sprayers. Read More
Scouting a soybean patch at Green Valley Ag.
EmployeesCropLife Compensation Survey: Battling Talent Drain
July 2, 2014
Retailers too often lose employees to companies outside of agriculture, while recruiting efforts are most often limited to competitors and other ag-focused organizations. Read More
HerbicidesDow AgroSciences Introduces SureStart II Herbicide
June 16, 2014
The enhanced formulation has improved viscosity and increased stability under heat and controls more than 60 high-anxiety grasses and broadleaf weeds found in corn fields. Read More
HerbicidesBASF Investing $270 Million To Expand U.S. Herbicide Production
June 11, 2014
BASF has invested more than $270 million to expand herbicide production capacities in the U.S., including more than 20 new products to be launched over next two years. Read More

Latest News

StewardshipMonsanto Joins Panel Of Innovators To Advance Research …
July 30, 2014
Monsanto Co. and The Climate Corp., its division, recently joined a roundtable of experts at the White House to share ideas and research approaches to help the world’s farmers manage and adapt to the impact of climate change on the global food supply. Read More
Crop InputsSoybean Checkoff Produces Big ROI
July 30, 2014
Under the soy checkoff program, all U.S. soybean farmers contribute a small percentage of their gross soybean sales for research and marketing projects that maximize their profit potential. Read More
CropLife 100Learfield Sports, CHS Agree To Football-Centric, Colleg…
July 30, 2014
CHS Inc. will embark on a highly integrated collegiate sports sponsorship platform with 24 Division I universities in 19 states designed to reach the farmer-owned cooperative's rural owners and customers. Read More
LegislationUSDA Implements Key Farm Bill Crop Insurance Provision
July 30, 2014
The new Supplemental Coverage Option, available through the federal crop insurance program and set to begin with the 2015 crop year, is designed to help protect producers from yield and market volatility. Read More
CropLife 100Wilbur-Ellis Forms New Organizational Structure For Its…
July 30, 2014
The new structure will provide more responsive internal support and will allow regional vice presidents and area managers to spend more time with customers, on talent development and on operational excellence across branches. Read More
Palmer pigweed in cotton
HerbicidesNew Training Modules On Herbicide Resistance Now Availa…
July 30, 2014
The Weed Science Society of America has announced the availability of three new education modules on herbicide resistance in weeds. Read More
HerbicidesWillowood To Market Glufosinate
July 28, 2014
Willowood USA recently announced that Federal EPA has approved its technical registration for glufosinate. Read More
InsecticidesHow To Scout For Corn Earworms In Corn
July 28, 2014
In her weekly report, University of Missouri Agronomy Specialist Jill Scheidt discusses what to look for when scouting for corn earworm. Read More
Crop InputsDuPont Pioneer, Weyerhaeuser Enter Technology License A…
July 28, 2014
The agreement brings together agricultural and forestry know-how to sustainably improve crop productivity for corn growers around the world. Read More
EquipmentAGCO Launches Global iPad App
July 28, 2014
The free AGCO Global iPad App can be downloaded from the Apple iTunes Store and features the full family of RoGator self-propelled sprayers and TerraGator high-floatation spreaders. Read More
Eric SfiligojYuma Centennial Ag Supply Earns 2014 National Environme…
July 28, 2014
Colorado-based ag retailer receives top trophy in 24th annual DuPont Crop Protection/CropLife ceremony. Read More
CropLife 100Pinnacle Forms Alliance With Wildlife Managment, Seed O…
July 25, 2014
The strategic alliance will provide Tecomate with key wildlife products, processing facilities, distribution centers and sales through Pinnacle’s ever-growing retail network. Read More
ManagementFranken Presses White House On RFS Support
July 25, 2014
Al Franken and a group of Senate democrats recently met with senior White House official John Podesta to urge the administration to change its position on an EPA proposal. Read More
ManagementASA, FarmLink To Launch ‘Operation Benchmark̵…
July 25, 2014
The American Soybean Association (ASA) and FarmLink are teaming up to help farmers close the $11 billion gap between what they harvested in 2013 and what they could harvest annually. Read More
StewardshipNorthey: Farmers Commit $1.4 Million to Try New Water Q…
July 25, 2014
The practices that are eligible for funding include cover crops, no-till or strip till and using a nitrification inhibitor when applying fall fertilizer. Read More
Precision AgFarmers Learn How Changing World Will Impact Iowa
July 24, 2014
Technology and understanding global consumer demand for Iowa farm products brought hundreds of farmers and agribusiness leaders to Ames recently for the annual Iowa Farm Bureau Federation Economic Summit. Read More
HerbicidesPurdue: Late Season Weeds May Require Manual Removal
July 24, 2014
Hand-rouging and pulling late season weeds by hand may be the best way to remove them, more so than using a herbicide, a Purdue Extension weed scientist says. Read More
Soybean Field
InsecticidesTransform WG, Closer SC Insecticides Receive R&D 10…
July 23, 2014
Dow AgroSciences has received the award from R&D Magazine for Transform WG insecticide and Closer SC insecticide with Isoclast active. Read More