Commodities

Practices

• 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

Problem

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.

Solution

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
phosphorus.

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.

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
   courses.
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.