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

Final Report for OW13-017B

Project Type: Professional + Producer
Funds awarded in 2013: $1,960.75
Projected End Date: 12/31/2015
Region: Western
State: Idaho
Principal Investigator:
Dr. Olga Walsh
University of Idaho
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Project Information


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.




Scientists and crop producers around the world are using crop canopy sensors to evaluate a crop’s nutrient status, estimate a crop’s biomass production, estimate a crop’s yield potential, detect crop stress and disease infestation, breed and select new crops, make fertilizer recommendations, and prescribe variable-rate fertilizer and chemical applications.

The purpose of this project was to improve growers’ knowledge and understanding of how crop canopy sensors and in-field reference strips can be utilized for effective nitrogen (N) management.

Project Objectives:

Objectives/Performance Targets

Specific objectives are:

  • 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.
  • To educate and train wheat growers on how sensor-based technologies can increase the efficiency and profitability of their wheat production operations.
  • To train graduate research assistants to utilize sensor-based technologies and to conduct on-farm research.


Click linked name(s) to expand
  • Kelli Belmont


Materials and methods:

The field research plots were established at the University of Idaho Research & Extension Center, Parma, Idaho. Spring wheat was seeded using a 5-foot research drill. The demo plots included a range of nitrogen fertilizer rates from 0 to 200 lb N/a applied in a strip using dry granular urea fertilizer at Feekes 5 growth stage (tillering). The 200 lb N/a fertilized plots were used as the non-limiting nitrogen reference strips. The plots were irrigated every 7 days using subsurface drip irrigation system buried at 8 inch depth. The amount of water to be applied at each irrigation event is determined by using Agrimet crop water use evapotranspiration-based model for spring cereal crops. The crop canopy reflectance measurements were taken throughout the growing season to access crop nutrient status. 

Research results and discussion:

The project helped us understand grower attitudes and knowledge level on precision ag and crop sensors. Field plots serves as excellent demonstration tools for growers and crop advisors attending extension outreach events. This allowed us to introduce the basic concepts of sensor-based technologies to ag producers and develop a collaboration network among ag professionals interested in advancing precision ag in the state of Idaho. This included incorporation of crop sensors and unmanned aerial systems for improved nutrient management.

Participation Summary

Educational & Outreach Activities

Participation Summary:

Education/outreach description:

An extension publication – “Efficient Nitrogen Management with Reference Strips and Crop Sensors” – was produced in collaboration with the University of Idaho College of Agriculture and Life Sciences Educational Communications office. The publications was distributed to field day attendees and at extension outreach events, commodity schools and grower seminars. Two technicians were trained in precision sensors use and in conducting agricultural research.

Project Outcomes

Project outcomes:

Grower survey on Precision agriculture adoption was conducted at grower meetings, field days, via list serv, in collaboration with commodity commissions, and on-line – SurveyMonkey and on Twitter and Blog) among ag professionals on nitrogen fertilizer and precision ag.

Total of 67 responses were collected to date. Survey will serve as a baseline for understanding grower attitudes and strategies on fertilizer management and to track progress of extending precision ag education and technologies adoption. 60% of responders indicated that nitrogen fertilizer is the most costly input in their farming operation. 80% use field records, 58% work with crop consultants, 5% use crop sensors to guide their nitrogen management. 100% recognize their fertilizer management is in need of improvement and that their fields are non-uniform and require changing fertilizer management from field to field and year to year. 50% indicated they are aware of precision ag research conducted in Idaho with 52% being aware of crop sensors for nitrogen management.

Economic Analysis

Economic analysis was not part of this project.

Farmer Adoption

In Idaho, adoption of sensor-based technologies is currently minimal, compared to other crop production areas of the U.S. This in part is due to high variation of agriculture practices: very large dryland fields in the north vs small area irrigated fields in south, complicated with highly diverse cropping systems which include a large number of crops. This poses challenges in terms of developing crop-specific and area-specific algorithms and ensuring farmer adoption. Very positive feed back was obtained from growers during seminars and field days in terms of acceptance of sensor-based technologies. 


Areas needing additional study

The proposed areas needing additional study are: developing effective methods of adoption of sensor-based technologies among growers, and demonstrating potential economic benefits of these technologies for farmers' bottom line vs associated investments in equipment and software. 

Information Products

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.