A Process-Based Nutrient Model for the Bedpack Manure of Confined Beef Systems

A Process-Based Nutrient Model for the Bedpack Manure of Confined Beef Systems

Summary

We conducted a lab-scale experiment to determine differences in ammonia, carbon dioxide, nitrous oxide and methane concentrations above simulated bedded beef manure bedded packs (in buckets) based on bedded manure age, bedding material, and temperature. The study showed that the higher storage temperature of 40 C significantly increased ammonia, carbon dioxide and methane concentrations approximately two-fold, compared to a cooler storage temperature of 10 C; nitrous oxide concentrations were only affected by temperature when soybean stubble was used as the bedding material. The methane concentrations significantly increased as the age of the bedded pack increased whereas carbon dioxide concentrations increased with age only at 10 C. Ammonia concentrations were significantly higher at 40 C with corn stover as the bedding material compared to soybean stubble. A process-based model will be designed with data collected from this experiment. Beef cattle producer input on model parameters and reporting units will be used to design the model.

Objectives/Performance Targets

My objective is to develop a process-based model that estimates quantity, quality, and fertilizer value for the bedded beef manure mixture. With this tool the producers have the potential to estimate how ambient air temperature, microbiology and bedpack characteristics (bedding material, age, and bedpack depth) impact nitrogen, potassium, and phosphorus transformation in the beef bedded manure. Producers can change their manure management practices accordingly to avoid nutrient losses to the environment in the form of gaseous emission, optimize fertilizer value and maintain a sustainable beef cattle operation.

Accomplishments/Milestones

The experimental data were collected and the gas concentration data have been statistically analyzed. These results and conclusions were presented at The 2013 Waste to Worth National Conference in Denver, Colorado, April 1-5, 2013. The presentation, abstract, and proceedings under the title “Ammonia and greenhouse gas surface concentration measurements from beef bedded manure packs” are available on extension.org.
During a stakeholder meeting with scientists and beef producers from SD, IA, and NE, I introduced the manure nutrient model which is still under development and the experiments I conducted so far. Relating to the model design, I presented a questionnaire for discussion. The questionnaire I developed will help glean more information from producers in which form (units) the results should be presented and which information would be most useful for them to obtain from the model. The discussion during the meeting helped me to refine the questionnaire and discuss methods to reach producers and receive their feedback on the survey. The discussion also showed that producers were very interested in a manure nutrient tool for beef bedded manure.

Impacts and Contributions/Outcomes

The calculator will facilitate beef cattle producers’ work and increase profitability by improving manure value and manure management practices in confined beef cattle barns. When applying this tool, beef producers will be able to predict quantity and fertilizer value of the bedded beef manure and thus over application of manure to compensate for manure value uncertainty can be avoided. At the same time nutrient losses to the environment as gaseous emission can be estimated and allow beef producers to obtain a sustainable operation.

Collaborators: