Progress report for SW24-014
Project Information
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
- Compare ammonia losses from variable rate manure application (VRA) with and without manure sensors with those of the most common CO manure management practices.
- 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).
- Compare the impact of variable rate dairy manure injection with and without manure sensors on crop yield and quality.
- Complete a cost-benefit analysis of dairy manure application with the use of manure sensors.
Education Objectives
- Incorporate research findings into existing undergraduate cropping systems, agroecosystem management, and manure management courses.
- Facilitate technology transfer via a Northern Colorado Manure Tech Demo Day and Extension bulletins.
- 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.
- Share findings and data with the broader community via a publicly available ammonia emissions database.
Cooperators
Research
Objective 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.
- To sample and quantify ammonia, we will follow a variation of methods outlined in Hoff et al., (1981). Using this approach, we will create microplots within each treatment strip. The number of microplots and samples required for adequate statistical analysis will be determined in conjunction with CoPI Archibeque and Stakeholder Andrews once the field locations and field mapping are finalized. Within each microplot, a steel cover with an acid trap and plastic hosing will be used to trap ammonia emissions and simulate air flux. Time intervals for sampling and duration of total sampling will also be determined based off Hoff et al., (1981), in addition to Keller (1986) and Erwiha et al., (2020). Similarly, to these approaches, we will measure ammonia emissions for 10 minutes every 3 hours during daylight. This schedule will be followed starting 24 hours after application and continue for 10 days as was done in Rochette et al., (2001). To build on these methods, we will take a sample 24 hours prior to application to capture flux before and after application. As ammonia sampling methods are variable, we will complete a pilot analysis to test method feasibility, quantify variability with the chosen method. Pre and post manure samples will be analyzed for N, P, K, pH, ammonium N, and nitrate N.
- Built 54 ammonia traps (see pictures below). Each trap holds five 20-mL scintillation vials, allowing for 200 vials total to be in the field at once. Traps consist of a 12-inch 2x4 plank with 2-inch holes carved across the plank. Magnets were glued at the bottom of the holes and scintillation vials to secure them in place during data collection. Scintillation vials will be filled with 10 mL of 6 M hydrochloric acid when capturing ammonia emissions during application. To simulate air flow, a plastic lid with two holes drilled into the side are placed over the trap. A piece of pipe runs through two holes. The width of the pipe was calculated using a 10x turnover rate for airflow within the plastic hood. The traps will be deployed to the field during manure application. Within each treatment replicate there will be three traps placed equidistant apart. Once all traps are placed appropriately, the scintillation vial lids will be removed and the plastic hood secured. Over the course of 72 hours scintillation vials will be replaced at predetermined time points to create an ammonia loss curve.
Objective 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).
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Baseline soil samples will be collected from each site at the start of the project in April 2024. Subsequently, soils will be sampled in the fall following silage harvest each season for all three years of the project to understand the impacts of treatments on key soil health parameters.
Within each field strip, we will collect two composite soil samples separated into two depth increments (0-20 cm and 20-40 cm). For the treatments with a fixed application rate, we will divide each strip evenly and collect one composite soil sample from each half strip. For the treatments with variable application rates, we will stratify our sampling approach to collect samples from an area that received above average and one area receiving below average manure application rates based on the application maps. We will then be able to scale the soil testing results using the application rate maps. Soil samples will be transferred to a cooler in the field, transported back to the lab, and refrigerated for further processing.
Soil samples will be processed to evaluate a suite of soil health parameters that reflect key soil functions and that are relatively sensitive to short-term management changes. To understand potential impacts on soil physical properties, we will measure bulk density using soil cores of known volume and wet aggregate stability on minimally disturbed soil samples (Elliott 1986) in the Fonte Lab. Bulk density and aggregate stability are key predictors of water infiltration and retention dynamics. The remaining subsample of soil will be sieved to 2mm and air-dried for soil C and N analyses. Impacts on SOM will be evaluated via total organic C as well as C and N in particulate organic matter (POM) and mineral-associated organic matter (MAOM) pools. The SOM fractions are thought to be more sensitive to management than total SOM and provide an indicator of the long-term trajectory of SOM levels (Lavallee et al. 2020). All soil organic C and N and manure N will be measured using an elemental combustion analyzer at the shared CSU EcoCore lab. Additionally, we will measure mineral N (2M KCl extractable ammonium and nitrate) to understand N availability using colorimetric methods in the Schipanski lab. Electrical conductivity will also be measured on all samples in the Schipanski lab as an indicator of salinity, an important concern in soils receiving frequent manure additions. Finally, a fresh 2mm-sieved subsample of soil will be freeze-dried and then analyzed by Regenerative Ag Labs for phospholipid fatty acid (PLFA) to understand the impact of manure application treatments on soil biological activity. The PLFA method provides broad information about bacterial and fungal microbial functional abundance (Bossio et al., 1998).
- We completed baseline sampling for the experimental site with the truncated treatments (injection only). The field was stratified into zones based on the patterns required to drag the hose for manure application and further broken into "high" and "low" yield zones based on data from the EOS crop monitoring database, which uses satellite imagery to predict NDVI. Summary statistics for the baseline soil data analyzed by the end of the reporting period are described below. Based on producer feedback, we made a minor adjustment to the treatments for the truncated experiment.
- Based on feedback from our participating producers and collaborators, we further clarified our variable application ate approach to be bounded by an additional factor: financial constraints in terms of the amount of manure they must apply (in addition to the already planned soil & manure testing-driven approach to defining application rates for each zone)
Objective 3. Compare the impact of variable rate dairy manure injection with and without manure sensors on crop yield and quality.
- Crop yield will be estimated using combine yield monitors, where available. If yield monitors are not available, yields will be collected by hand. From each replicate, corn plants from 5.3m of crop row (representing 1/1000th of an acre) will be cut and weighed in the field using a hanging scale. Biomass will be chopped in the field using a biomass shredder and a subsample will be collected for quality analyses conducted in the Archibeque lab. Samples will be analyzed for crop N, P, K, starch, sugar, ash, neutral detergent fiber (NDF), and acid detergent fiber (ADF) using near infrared resonance (NIR) calibrated and validated using wet chemistry analyses of sorghum silage.
- This growing season will be the first application of treatments and yield data will be collected in fall.
Objective 4. Complete a cost-benefit analysis of dairy manure application with the use of manure sensors.
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The producers and industry collaborators are interested in the economic feasibility of this type of technology. As such, we will calculate the cost-benefit and/or return on investment of the manure sensors for each year. Purchase price of manure sensors, fuel, and fertilizer value of manure will be used. It will be estimated with and without the assumption that the use of the technology to apply dairy manure replaces some synthetic nitrogen fertilizer application. Yield data and a range (high, medium, and low) forage market prices will be used to estimate economic returns for each treatment. We will then estimate the break-even time point for the manure sensing technology investment.
The following analyses are complete for the field with the truncated experiment: soil (MAOM/POM fractionation, KCl extraction, Bulk density, PLFA, soil mineral analyses (NH3+ and NH4+), EC analysis, pH analysis, total C, and total N). We have also obtained the geolocated total manure, N, P, and K application rates from the HarvestLab. Lastly, we obtained historical yield data from the EOSDA Crop Monitoring program. The following analyses are underway: manure P, K, NO3-, NH4+, EC, total C, and total N.
Due to circumstances outside of our control, the producer who was applying the full set of treatments to his fields dropped out of the study. We are working diligently with our networks to identify another producer to collaborate with and have several leads we are pursuing here in CO and in the Midwest.
Research Outcomes
We are in year 1 of the project and do not yet have recommendations.
Education and Outreach
Talk: "Beyond the Barnyard: Optimizing Nutrient Efficiency in Colorado's Dairy Production Through Precision Manure Management with NIRS Technology" Presented at the 2024 CSU Hydrology Days, Fort Collins, CO. April 17, 2024. Andrea Loudenback
Participation Summary:
Objective 1. Incorporate findings into existing cropping systems, agroecosystem management, and manure management courses.
- Together with the graduate student, professors will develop course slides, evaluations, and activities that integrate the knowledge gained from this project into their courses. Research findings, videography, and imagery generated from this project will be incorporated into their course content as modules developed in the final year of the grant. These may include videos and photographs from the experiment and demo day. Collaborator Rieder has also offered to talk with courses or demo the technology for classes, schedule permitting.
Objective 2. 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.
- Collaborator Heese, an experienced manure application school trainer, will attend from IA to co-facilitate the training with the graduate student on the project. The trainer uses inquiry-based learning and recitation as primary modes for delivering information. In general, previous trainings held by this trainer have not been place based, and instead serves to inform producers of the general knowledge required for manure application. Along with Collaborator Heese, CoPI Caswell and the graduate student on the project will work to revise the materials to be specific to manure management in Colorado.
Objective 3. Facilitate technology transfer via a Northern Colorado Manure Management Demo Day and Extension bulletins.
- Recruit producers
- Producers will be recruited to the event through several modes, including advertising through CSU Extension’s online presence, contacts at county extension offices, the USDA ARS network Collaborator Kleinman is connected with, and via relevant email listservs. The templates provided in the SARE Farmer Field Day Toolkit will be used to design extension outreach materials.
- Collaborator Hunter Pierce (21st Century Equipment) will organize their media team to coordinate with CoPI Caswell to recruit producers through radio, online, and word-of-mouth. Lastly, to reach a different contingent of producers and stakeholders involved in manure management throughout the state, the graduate student on the project will attend and/or present at major agricultural events in Colorado, such as Dairy Days, the Colorado Farm show, and National Western Stock Show, leading up to Demo Day.
- Began informal recruiting through related manure management work with collaborators from USDA.
- Host the demo day
- At the Demo Day producers will arrive in the morning for presentations overviewing the project, how precision manure management may contribute to reducing the environmental impacts of manure management, and results from the study. After the morning session, producers will break for lunch before being transferred to the experimental sites to view the fields, experimental design, and the manure sensor in use. Collaborators Joe Heese, Alex Rieder, Grayson Rieder, and Hunter Pierce will walk producers through the machine set up, the pumping equipment necessary for this type of manure application approach, and how to use the sensor. Collaborator Casey Andrews will assist the research team in presenting the virtual field mapping and contributions ot the field design. To conclude the field portion of the Demo Day, attendees will have the opportunity to watch collaborators Alex Rieder and Grayson Rieder apply manure via the injection method and with the manure sensor.
- Initial planning for the demo day activities began this year. We are in discussions about hosting this in conjunction with a larger convening of producers and researchers interested in manure management because we identified there will be a lot of overlap in attendees. We are exploring the option of hosting the events in conjunction with one another to be sensitive to the time constraints faced by producers.
- At the Demo Day producers will arrive in the morning for presentations overviewing the project, how precision manure management may contribute to reducing the environmental impacts of manure management, and results from the study. After the morning session, producers will break for lunch before being transferred to the experimental sites to view the fields, experimental design, and the manure sensor in use. Collaborators Joe Heese, Alex Rieder, Grayson Rieder, and Hunter Pierce will walk producers through the machine set up, the pumping equipment necessary for this type of manure application approach, and how to use the sensor. Collaborator Casey Andrews will assist the research team in presenting the virtual field mapping and contributions ot the field design. To conclude the field portion of the Demo Day, attendees will have the opportunity to watch collaborators Alex Rieder and Grayson Rieder apply manure via the injection method and with the manure sensor.
- Program evaluation
- To evaluate the program and knowledge gained, producers will complete identical pre and post surveys to assess their level of manure application knowledge before and after the event. The questionnaire will include general questions such as “Have you ever seen manure injection in practice?” and Likert scale questions such as “How likely are you to hire a custom applicator who uses manure injection practices?”. We will also ask producers to rate the usefulness and allow them the opportunity for open-ended feedback about the event so that we can use their feedback to improve outcomes from similar events in the future. The evaluation will collect farm and farmer demographics including operation size and length of time working in agriculture to evaluate differing levels of experience and approaches to management decisions. Additionally, all participants will be asked to answer standard demographic questions.
- To evaluate the program and knowledge gained, producers will complete identical pre and post surveys to assess their level of manure application knowledge before and after the event. The questionnaire will include general questions such as “Have you ever seen manure injection in practice?” and Likert scale questions such as “How likely are you to hire a custom applicator who uses manure injection practices?”. We will also ask producers to rate the usefulness and allow them the opportunity for open-ended feedback about the event so that we can use their feedback to improve outcomes from similar events in the future. The evaluation will collect farm and farmer demographics including operation size and length of time working in agriculture to evaluate differing levels of experience and approaches to management decisions. Additionally, all participants will be asked to answer standard demographic questions.
- Develop a series of bulletins about variable rate manure application, including the use of the sensors. This information will complement existing CSU Extension literature on manure management for reducing ammonia emissions from manure application (e.g., Best Management Practices for Reducing Ammonia Emissions: Manure Application, Best Practices for Manure Utilization). These publications will be annual communication pieces and fact sheets posted to the extension website leading up to the Demo Day. Additionally, further publications surrounding general best management practices for manure management and manure as a resource may be advised by CoPI Caswell and added to the communication pieces published through CSU Extension.
- Began reviewing existing CSU Extension materials and developing a plan of action for updating materials over the course of the next year of the grant.
Objective 4. Share findings and data with the broader community via a publicly available ammonia emissions database.
- In addition to being made available via Extension, CoPI Dillon will lead the process of uploading the data to the AFAM2 database, a global, open-source AMMONIA emissions database designed to facilitate international research on mitigating AMMONIA emissions (Hafner et al., 2018).
Education and Outreach Outcomes
We anticipate having recommendations in a future progress report.