## 2 Materials and Methods
### Scientific Background of Data Requirement and Modules of AGEM-S
#### 2.2.4 Manure Storage Module  
After leaving the livestock building, or occasionally after passing through certain treatment methods, manure of different consistencies is disposed of in storage until the date of use. Emissions from manure storage are influenced by the chemical composition and physical characteristics of the manure (dry matter content, pH); the characteristics of the emitting surface (size, crust, cover); climatic conditions (ambient temperature, rain, wind); and, in the case of solid manure, the compostability potential (water content, density, carbon content) [44]. \begin{table}
\begin{tabular}{c c} \hline \hline Name of the stable & \\ \hline Place for pigs in stable & \\ \hline \multirow{4}{*}{Function of the stable} & nursery \\ \cline{2-3}  & mating and gestating unit \\ \cline{2-3}  & weaner unit \\ \cline{2-3}  & grower/finisher unit \\ \cline{2-3}  & replacing gilt unit \\ \hline Days in free range (optional) & \\ \hline \multirow{4}{*}{Housing techniques} & typical housing techniques in Hungary: outdoor; \\  & litter-based housing: daily manure removal or \\ \cline{2-3}  & deep litter; \\  & slurry-based housing: fully or partly slatted floor, \\ \cline{2-3}  & concrete floor with manure channel \\ \hline \multirow{4}{*}{Mitigation techniques} & frequent manure removal with vacuum, flushing \\ \cline{2-3}  & gutters, cooling manure surface, feeding stalls and \\ \cline{2-3}  & manure pit with slanted walls, floating balls on \\ \cline{1-1}  & manure surface, water and manure channels, manure \\ \cline{1-1}  & pan underneath, partially slatted floor with reduced \\ \cline{1-1}  & pit, partially slatted floors and flushing gutters, \\ \cline{1-1}  & technology used in the stable \\ \cline{1-1}  & partially slatted floor and collection in acidified liquid, \\ \cline{1-1}  & partially slatted floor and cooling manure surface, \\ \cline{1-1}  & partially slatted floor and manure channel with \\ \cline{1-1}  & slanted walls, air scrubbing techniques (according to \\ \cline{1-1}  & [PERSON] et al. [1]) \\ \hline \hline \end{tabular}
\end{table} 
Table 3: The input data requirements of housing modules. During storage, the manure should be isolated from the ambient air, and the surface area of the manure should be reduced to achieve the lowest possible ammonia emissions; otherwise, physical and chemical degradation processes could be enhanced [59; 60]. Techniques that can be used to cover the surface of the storage include the application of a layer of sprayed straw on the surface of the manure, floating films, plastic covers, roofs, and other materials such as oil or peat [61]. The natural crust that forms on the surface of the stored slurry depends on its dry matter content and on the local climatic conditions. Frequent mixing should be avoided, and tanks should be filled and emptied below the liquid level to avoid disruption of the crust that forms [44]. Ammonia emissions can be reduced by lowering the temperature [62] or by lowering the pH of the slurry [44; 63]. In the case of solid manure, the phenomenon of self-heating, which triggers the composting process, must also be taken into account; this also affects ammonia emission, and it is therefore recommended to cover the manure pile to limit air flow, which can be reduced by manure compaction [56]. The AGEM-S storage module treats litter-based manure and slurry separately, taking into account the average annual volumes stored, the type of storage, and the physical characteristics (size, coverage) that determine the amount of ammonia emissions. The ER and CF values are estimated according to [PERSON] [31] and [PERSON] et al. [1]. The basic unit of the module is the manure storage. The data requirements of the model are annual quantitative data on manure production, storage, and sale, as well as the volume and surface area of the storage facilities (Tables 4 and 5). If the farm has more than one storage type, aggregated volume and surface area data are required.