Reference strips and precision sensors for increased nitrogen use efficiency in wheat production

Final Report for OW13-017

Project Type: Professional + Producer
Funds awarded in 2013: $49,907.00
Projected End Date: 12/31/2015
Region: Western
State: Montana
Principal Investigator:
Dr. Olga Walsh
Montana State University
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Project Information


While nitrogen is a key nutrient limiting wheat grain production, its use efficiency is only about 30%. As nitrogen is lost via volatilization and plant loss, run off and leaching, immobilization and denitrification, about 70% of funds wheat growers invest annually in nitrogen fertilizer is being lost as well. Non-limiting nitrogen reference strips in combination with precision sensors such as GreenSeeker® (Trimble Navigation Ltd., Sunnyvale, CA) has been successfully used throughout the Midwest and elsewhere to accurately estimate crop yield potential and the crop’s prospective responsiveness to nitrogen mid-season. This methodology enables producers to generate topdress fertilizer recommendations based on crop’s precise requirement for nitrogen. This system helps to significantly increase nitrogen use efficiency and has been shown to net wheat growers more than $25 per acre in fertilizer savings. Researchers at Montana State University are aiming to develop algorithms for Montana wheat varieties and growing conditions within two to three years. This project was focused on ensuring that wheat growers are prepared to successfully utilize the algorithms and are equipped with knowledge and expertise to fully benefit from sensor-based technologies.


Our project is focused on educating and training wheat producers on how sensor-based technologies can increase the efficiency and profitability of their farm operations. Precision sensors enable to develop crop-specific and site-specific yield potential-based topdress nitrogen recommendations and to increase nitrogen use efficiency. Sensor-based nitrogen management strategies directly results in:

i. satisfaction of human food needs (due to efficient and sustainable production of wheat - principle food grain produced in the United States)
ii. improving the environmental quality (fertilizer is applied strictly based on crops need for nitrogen, which optimizes nitrogen uptake and minimizes nitrogen loss to the environment; non-source pollution associated with intensive crop production is reduced)
ii. making the most efficient use of nonrenewable resources and on-farm resources and integrate, where appropriate, natural biological cycles and controls (enables to account for spatial and temporal nutrient variability present in agricultural fields and optimizes the use of non-renewable resources such as soil nutrients, and on-farm resources such as fuel, time, and labor)
iv. sustaining economic viability of farm operations (increased efficiency of grain producing operations - significantly minimized annual losses to producers due to improved nutrient management strategies)
v. enhancing the quality of life for farmers and society as a whole (due to making farming operations more efficient and providing substantial savings in fertilizer inputs, fuel and labor, as well as improved environmental quality; agricultural education and outreach components of the project will significantly increase growers' ability to make more informed nutrient management decisions; feeling in control of their financial investments in fertilizers will ensure the improved quality of life for growers, their families and their communities as a whole).

  • Wheat production covers over 5,000,000 acres of agricultural land, employs approximately 15,000 individuals, and accounts for approximately 25% of Montana’s total agricultural revenue.
  • Rural farming communities have greatly benefited from this project through enhanced knowledge of precision agriculture techniques and improved decision-making skills for more profitable farm operations management. With 787, 472, 836, 520, 700, 405, 1037, and 297 individual farm operations in Chouteau, Glacier, Hill, Pondera, Teton, Toole, Cascade, and Liberty counties, respectively, we have reach over 5,000 crop producers within Golden Triangle – Montana’s key grain growing area. A precision nutrient management blog has ensured that project's milestones and successes are effectively communicated to a much broader grower audience in Montana, other regions of the United States, and elsewhere.
  • The agricultural sector is experiencing lack of excellent agricultural specialists trained to employ cutting edge technologies and to have the expertise to successfully work with growers. We have trained a graduate student in sensor-based nutrient management and in conducting of on-farm research studies.

Project Objectives:

This project’s objectives and expected outcomes are directly related to the definition of sustainable agriculture as defined by the U.S. Code Title 7, Section 3103 of the U.S. Congress.

1. To establish on-farm studies to demonstrate that non-limiting nitrogen reference strips - in combination with precision sensing methodologies – can be effectively used to accurately determine wheat demand for nitrogen.
2. To educate and train wheat growers on how sensor-based technologies can increase the efficiency and profitability of their wheat production operations.
3. To train graduate research assistants to utilize sensor-based technologies and to conduct on-farm research.


Click linked name(s) to expand/collapse or show everyone's info
  • Korey Fauque
  • Jeff Habets
  • Scott Inbody
  • Lindsey Martin
  • Jack Patton


Materials and methods:

1. To establish on-farm studies to demonstrate that non-limiting nitrogen reference strips - in combination with precision sensing methodologies – can be effectively used to accurately determine wheat demand for nitrogen.

Five on-farm demonstration plots were established in the fall 2013 and spring 2014 within the cooperating wheat producers’ fields (Fauque, Habets, Inbody, Martin, Patton). The demo plots included a range of nitrogen fertilizer rates from 0 to 200 lb N/a applied in a strip using liquid urea ammonium nitrate (UAN) solution and a stream-bar sprayer-equipped ATV. The 200 lb N/a fertilized plots were used as the non-limiting nitrogen reference strips at each location. The research plots were used as visual aids during the two field days organized for growers in 2014 – one near Western Triangle Agricultural Research Center, Conrad, MT in May 2014, and the second – at Jack Patton location (July 2014). Local growers were from the surrounding counties were invited to participate in the field days. The events were advertised though the Montana State University’s Extension personnel and media channels.

At the first field day (May 2014), the 12 participating growers were presented with the general background information about precision sensors, their potential benefits, and utilization methodologies. The presented information included step-by-step instructions for establishment of non-limiting nitrogen reference strips, the basic sensor set-up, and the general light reflectance concept. The meeting incorporated an interactive discussion and workshop on standard sensor use and data collection.

At the second field day (July 2014) the 23 participating growers were asked to rate the demo plots according to their visual evaluation and to identify the plots that appeared to have relatively poor and relatively well-established crop stands. The graduate student (Arjun Pandey) and the precision soil nutrient management crew members have then compared the grower rating results with the GreenSeeker NDVI measurements. In most cases, the visual evaluation of the plots did not correspond to the NDVI readings. In terms of utilizing the observations and the sensor data for prescribing topdress N fertilizer rates for wheat, he visual observation would result in substantial over-fertilization, compared to sensor-based recommendations.

2. To educate and train wheat growers on how sensor-based technologies can increase the efficiency and profitability of their wheat production operations.

• The following grower attended events were utilized to disseminate the information relevant to this project and to educate growers on the remote sensing and precision agriculture issues:

  1. Grower meeting - Western Triangle Agricultural Research Center, Conrad, MT, January 10, 2013, number of attendees – 20. 
  2. Field day – Northern Agricultural Research Center, Havre, MT, June 26, 2013, number of attendees – 300 (
  3. Field day - Western Triangle Agricultural Research Center, Conrad, MT, July 10, 2013, number of attendees – 275 (
  4. Grower tour - Soil Nutrient Management in Montana’s Golden Triangle. Farming Smarter Canada producer tour. July 11, 2013. Attendees – 15.
  5. Choteau County Crop Tour, Knees, MT, June 19, 2013, number of attendees – 19.
  6. Grower meeting - Western Agricultural Research Corvallis, MT, May 20, 2013, number of attendees - 25.
  7. Agricultural Research/Teaching/Outreach panel. Dutton High School, Dutton, MT, April 25, 2013, number of attendees – 25.
  8. Grower meeting - Western Triangle Agricultural Research Center, Conrad, MT, September 16, 2014, number of attendees – 85.
  9. InfoAg Conference: Springfield, IL, June 16-18, 2013, number of attendees – 169 (
  10. Montana Grain Growers Association Convention: Great Falls, December 3-5, 2013, number of attendees – 178
  11. Golden Triangle Cropping Seminar, MSU Extension. Fort Benton, Denton, Shelby, Chester, Cut Bank, Conrad, Choteau, and Great Falls, MT. January 13-16, 2014, number of attendees – 241 (

• An educational outreach Precision Agriculture Seminar was organized and delivered in October 2013 in Great Falls, MT. The seminar was extensively advertised in the media:


• Wheat growers were invited to travel and participate in the annual nitrogen Use Efficiency workshops, Johnston, IA (August 2013) and Sioux Falls, SD (August 2014) ( Although no growers expressed the interest in attending these workshops, the information presented at the meetings was disseminated via Precision Nutrient Management Blog, as well as by e-mail list-serve.

Graduate student, Arjun Pandey, and Research Associate, Robin Christiaens, have attended both workshops and got the opportunity to interact and network with researchers and growers involved in precision nutrient management in other regions of the United States and abroad.

3. To train graduate research assistants to utilize sensor-based technologies and to conduct on-farm research.

For the period of May 2013 – October 2014, graduate student, Arjun Pandey, received continuous training on working with crop producers on establishing experimental research plots, collaborating with growers in terms of coordinating field work operations and data collection, presenting research results at grower meetings, and conducting workshops. He has received an extensive training in remote sensing and precision agriculture methodologies, including formal classroom instruction, in-field hands-on training on the use of precision sensors, and data collection and analysis.

Research results and discussion:

Results from Objective #1's study are in the figures attached.

In summary, growers’ visual ratings were directly proportionate to the labeled N rates applied to each plot. As the N rate increased, the growers' perception of the crop stand has improved, resulting in a higher rating scores (Figure 1). The NDVI data (Figure 2) shows that no increase in the crop stands’ vigor and greenness was detected above the 100 lb N/a rate. This supports previous findings that remote sensing allows for much more precise crop stand assessment compared to traditional visual evaluation. Furthermore, results illustrate that sensors can be an effective tool in identifying nitrogen deficient and adequately fertilized plots/areas of the field and, thus, developing topdress nitrogen recommendations to correct early to mid-season nitrogen stress and to fertilize wheat crop according to its need.

Participation Summary

Research Outcomes

No research outcomes

Education and Outreach

Participation Summary:

Education and outreach methods and analyses:

• Precision Nutrient Management Blog ( – active 2013 – 2014; number of visitors/followers – over 6700.
• Extension brochure “Reference Strips for Efficient Nutrient Management” has been published in 2013. One thousand hard copies have been distributed at grower meetings, field days, and through the MSU county extension offices throughout the state of Montana. The publication was also posted to the Precision Nutrient Management Blog.
• A radio segment on Western SARE-funded project focusing on precision sensors and grower education. MSU Extension Minute with Pondera County Agent Dan Picard, on K96FM, Shelby, MT, February 27, 2013. Reached over 30,000 listeners within Glacier, Pondera, Toole, Liberty & Teton Montana counties (

Education and Outreach Outcomes

Recommendations for education and outreach:

Areas needing additional study

Further work is needed in evaluating the specific needs of growers in terms of what kind of information and skills they require/lacking in order to successfully implement precision agriculture tools and methodologies in their farming operations. Further work is needed to develop closer networking among growers, crop consultants, and agricultural extension personnel to conduct collaborative precision agriculture research.

Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the view of the U.S. Department of Agriculture or SARE.