Predicting methane emission from liquid manure and exploring mitigation options with integrated farm-scale modelling using the ABM model

Frederik Rask Dalby*, Sasha D. Hafner, Anders Peter S. Adamsen

*Corresponding author af dette arbejde

Publikation: KonferencebidragKonferenceabstrakt til konferenceForskningpeer review


Manure management is a significant source of methane emission globally, and various national efforts are aimed at reducing this source through changes in management. Methane is produced by slow-growing archaea, making methane production sensitive to management and accurate prediction with simple models challenging. However, the slow growth of methanogenic archaea presents a unique opportunity for reducing emission from pig and cattle slurry pits or outside manure storages through simple manure management changes.
In this work we will describe the Anaerobic Biodegradation Model (ABM) (Dalby et al., 2021), which explicitly considers microbial growth for predicting methane emission from stored liquid manure. We validated the model using full-year in-house methane emission measurements from a pig house. Using the validated parameter set (Dalby et al., 2023) we will demonstrate how ABM can be used for predicting barn and outside storage methane emission from cattle and pig liquid manure at the farm level.
ABM is a flexible mechanistic model that includes multiple groups of methanogens, each with a specific temperature response. It is currently available as an R package. It tracks organic matter conversion to volatile fatty acids, which in turn is converted to methane by distinct methanogenic groups. In the latest developments, multiple ABM simulations were integrated to track organic matter and microbial population flows from the animal to barn to outside storage environment. Different manure management mitigation options were explored by “building” the desired farm management in a separate spreadsheet input template. At barn level, parameters such as excretion of organic matter from the animals, design and management of pen floors and slurry pits were included.
Results and discussion
We explored mitigation options and found that temperature, manure removal frequency, residual slurry level, and application time of the slurry to the field was important for farm-scale methane emission. Methane emissions from storages was larger than from barn in both pig and cattle farms at Danish conditions, where farmers store the major part of the liquid manure in outside storages. Consequently, at pig farms methane emission could be reduced by more than 20% by reducing the amount of manure stored outside during the warm season with field application over the summer. At cattle farms, weather was more important because in-barn manure temperature was affected by the outside temperatures in the open ventilated barn. Hence during cold years ~15% less methane would be emitted from cattle manure at the farm level.
Methane emission prediction and exploration of mitigation options is possible with a dynamic model that considers microbial growth and links organic matter flows between the different emission sources.
Publikationsdato12 sep. 2023
Antal sider1
StatusUdgivet - 12 sep. 2023
BegivenhedRAMIRAN - Cambridge, Storbritannien
Varighed: 12 sep. 202314 sep. 2023
Konferencens nummer: 18