Variable Rate Manure Application with Real-Time Nutrient Sensing for Improved Soil Health and Reduced Environmental Impacts of Dairy Manure Use

Project Overview

Project Type: Research and Education
Funds awarded in 2024: $349,819.00
Projected End Date: 03/31/2027
Grant Recipient: Colorado State University
Region: Western
State: Colorado
Principal Investigator:
Dr. Jasmine Dillon
Colorado State University
Dr. Shawn Archibeque
Colorado State University
Kat Caswell
Colorado State University
Dr. Steven Fonte
Colorado State University
Meagan Schipanski
Colorado State University


Not commodity specific


  • Animal Production: manure management
  • Crop Production: application rate management, nutrient cycling, nutrient management
  • Education and Training: demonstration, extension, farmer to farmer, on-farm/ranch research, workshop
  • Farm Business Management: budgets/cost and returns
  • Natural Resources/Environment: carbon sequestration, soil stabilization
  • Production Systems: agroecosystems, dryland farming, integrated crop and livestock systems
  • Soil Management: nutrient mineralization, organic matter, soil analysis, soil chemistry, soil microbiology, soil quality/health

    Proposal abstract:


    Although manure is a high-quality soil amendment, its management
    system can degrade air and water quality. Manure nitrogen
    volatilization as ammonia impacts both human health through the
    formation of atmospheric PM2.5 and reduces biodiversity through
    deposition in natural areas such as Rocky Mountain National Park.
    Northern Colorado’s semi-arid environment combined with common
    manure management practices such as open lots, uncovered manure
    storage, and broadcast manure application make dairy systems
    hotspots for ammonia emissions in the state.


    Variable rate application (VRA), a precision manure management
    strategy, adjusts manure volume application to reduce
    over-application of manure nutrients. While VRA by volume
    provides more control over nutrient placement within a field,
    over- or under-application of some nutrients due to the inability
    to adjust rates based upon manure’s heterogeneous nutrient
    composition or to optimize application rates for multiple
    nutrients. For example, setting application rates by volume to
    meet plant nitrogen needs may result in over-application of

    Recent advancements in VRA use NIRS sensors to measure manure
    nutrient composition real-time, enabling autonomous adjustment of
    application rates in the field. This technology refines existing
    VRA technology as it can be optimized for multiple criteria
    (e.g., minimize both nitrogen and phosphorus), which may
    further reduce environmental impacts by more precisely matching
    application rates to plant needs.

    This project was developed in coordination with local manure
    applicators, a dairy farm manager, a large dairy operator, and
    dairy industry partners including a manure management school
    facilitator, an equipment dealer, and a manufacturer. The
    objective of this proposal is to evaluate the potential for
    manure sensors to contribute to reduced ammonia losses from
    manure application and improve soil health in Colorado’s
    croplands. Its findings will be disseminated in coursework and a
    demo day hosted in collaboration with CSU Extension, 4Rivers
    Equipment, and Puck Enterprises.

    Project objectives from proposal:

    Research Objectives

    1. Compare ammonia losses from variable rate manure application
      (VRA) with and without manure sensors with those of the most
      common CO manure management practices.
    2. Evaluate the impact of variable rate manure injection with
      and without the use of NIRS manure sensors on soil N dynamics and
      key soil health parameters (g., bulk density, soil
      organic carbon, aggregate stability, electrical conductivity, and
      soil microbial communities).
    3. Compare the impact of variable rate dairy manure injection
      with and without manure sensors on crop yield and quality.
    4. Complete a cost-benefit analysis of dairy manure application
      with the use of manure sensors.


    Education Objectives

    1. Incorporate research findings into existing undergraduate
      cropping systems, agroecosystem management, and manure management
    2. Facilitate technology transfer via a Northern Colorado Manure
      Tech Demo Day and Extension bulletins.
    3. Provide a professional development opportunity by offering an
      optional 2-day manure management training in conjunction with the
      demo day, with the opportunity to earn a manure management
      certificate upon completion.
    4. Share findings and data with the broader community via a
      publicly available ammonia emissions database.


    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.