## 3 Results and Discussion
\begin{table}
\begin{tabular}{c c c c c c c} \hline \hline \multirow{2}{*}{**Sample**} & \multicolumn{4}{c}{**Primary and Secondary Macronutrients, \%**} & \multirow{2}{*}{**Organic**} \\ \cline{2-2} \cline{4-7}  & \(\mathbf{N_{total}}\) & \(\mathbf{P_{2}O_{5}}\) & \(\mathbf{K_{2}O}\) & \(\mathbf{CaO}\) & \(\mathbf{MgO}\) & **Matter, \%** \\ \hline
2 & 4.73 & 4.26 & 6.47 & 2.94 & 1.45 & 32.46 \\
7 & 3.87 & 5.29 & 8.28 & 2.10 & 1.13 & 31.31 \\
10 & 4.42 & 6.23 & 12.15 & 3.43 & 1.58 & 22.18 \\
15 & 3.56 & 5.96 & 12.37 & 3.85 & 2.06 & 22.25 \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Concentrations of primary and secondary macronutrients in the biofertiliser samples. Figure 2: Images of granular product (size 3.15–4 mm) samples: (**a**) 2; (**b**) 7; (**c**) 10; (**d**) 15. Figure 3: _Cont._  
It is important to mention that the numerical values of the concentrations of some other plant nutrients, such as P (as P\({}_{2}\)O\({}_{5}\)), calcium (as CaO), and magnesium (as MgO), determined by chemical analysis methods (Table 3), correlate well with the data of element maps (Figure 3). However, in samples 10 and 15, a significantly lower concentration of potassium (as K\({}_{2}\)O) was determined by the chemical analysis (Table 3) method than by EDS (Figure 3). Evaluating the composition of sample 10 (composition V) and sample 15 (composition VI), it can be assumed that this is due to the insoluble form of potassium present in the ash. Because all fertilisers are more or less hygroscopic (which means that they start to absorb moisture at a specific level of humidity or at a certain water vapour pressure; this plays a role in fertiliser losses during storage [68]), the hygroscopicity of the granular products was determined (Figure 4). Figure 4 shows that these are classical absorption curves, in that they initially rise upwards while the biofertiliser absorbs moisture from the environment and fluctuate minimally depending on environmental conditions once equilibrium is reached. When  
Figure 3: SEM–EDS data of granular product (size 3.15–4 mm) samples: (a) 2; (b) 7; (c) 10; (d) 15.  
the biofertiliser samples are stored in a saturated sodium nitrite environment (62-63% of relative humidity), the equilibrium is reached after 4-5 days and the maximum absorbed moisture content is 5-6% with the BE binder and 8-9% with the MS binder (Figure 4a). Unlike mineral fertilisers [67], organic biofertilisers are not under threat of caking, but they start to mould due to the bioactive substances in the fertiliser. Mould was recorded in all biofertiliser samples after 5-7 days of storage in an environment of 99.5% relative humidity of water vapour. Again, the moisture uptake was higher in the biofertilisers with MS as the binder than in the fertiliser granulated with BE, i.e., 35-38% and 27-28%, respectively. Such absorption is significant and may have undesirable consequences for fertiliser products: the particles gradually become soft and sticky, the particles begin to break up and discolour, and the strength of the particles decreases [69]. Therefore, such fertilisers require appropriate storage conditions or the selection and application of biodegradable coatings on the fertiliser in the conditioning drums. However, given that such organic fertilisers are already classified as slow-release fertilisers, a coating would further slowdown the entry of nutrients into the plant. The evaluation of the granulation of these organic biofertilisers under laboratory conditions and of the properties such as the granulometric composition and moisture content of the product, allows one to distinguish the main stages of production of organic biofertilisers, as follows: preparation of the raw materials and the binder; mixing of the solid and liquid raw materials; granulation; fractionation; return of recycled material; drying; packaging; storage. All these stages are presented in Figure 5 as a technological scheme of the principal process.