## 3 Results
### Results of Statistical Analysis  
The possible effect of the most common treatments on the potential toxic elements and macro and micronutrient content was examined. The grouping of the samples according to the treatments was as follows:  
1 = Monthly turning, MT (Samples A, B, H)  
2 = Monthly turning, moistening, MTM (Samples C, D)  
3 = No treatment, NT (Samples E, F, K, L)  
4 = Addition of earthworms (not red worms), AE (Samples G, J, M)  
5 = Periodic turning, addition of earthworms, PAE (Sample I)  
6 = Periodic turning, moistening, PTM (Samples N, O, P)  
The variance of homogeneity and significant differences in category means are present simultaneously only for Zn and Mg: zinc as a potential toxic element, and magnesium as a macronutrient. A post hoc test could not be performed because treatment 5 (periodic turning and addition of earthworms) had only one element. As there was no post hoc test, the visual representation of the means provides a basis for judging differences between groups.  
It can be seen from Figure 2 that the largest difference is between treatments 3 and 6 in terms of Zn content.  
In terms of the effect on Mg content, there was the largest difference between treatments 2 and 3 that can be seen in Figure 3.  
Figure 3: Average comparison of Mg. Note: unit of measure is mg \(\times\) kg\({}^{-1}\) d.m.  
Figure 2: Average comparison. Note: unit of measure is mg \(\times\) kg\({}^{-1}\) d.m.  
In the cases wherein no treatment was applied, the Mg content was at the lowest level, while the zinc content, which is a potentially toxic element, was the highest. The latter was true even for lead, cadmium, and chromium. In the case of the untreated compost, however, the Ca content was at the lowest level. The effects of the raw materials on toxic element content and macro and microelement content were also examined. The ingredients of the raw materials of the examined composts were very diverse. In order to compare the samples, five categories were created, taking into account the chemical properties of the ingredients and their main components' effect on the microbial activity. Components that have a differentiating effect on the quality parameters of the composts, such as the effect on the toxic element and macro- and micronutrient content, were selected. According to this, the following categories were created:  
1 = GGW-garden green waste only (Samples A, B, J)  
2 = M-Use of manure (Samples H, L, P)  
3 = S-Use of soil and wood ash (Samples E, F)  
4 = WL-Walnut leaves (Samples N, O)  
5 = GGW and others (Samples C, D, G, I, K, M)  
Category averages differed significantly for Cd, Cr, Ni, and Fe. The post hoc (Scheffe) test was feasible in this case and showed a significant difference between raw material categories 3 and 4 (Figure 4). Thus, cadmium levels were highest in terrestrial raw materials, while they were lowest in walnut leaves. The latter includes the fact that the walnut leaf was of organic origin.  
The raw material had an effect on the level of the Cd (Figure 4). Category averages differed significantly for cadmium and iron when we analyzed the impact of the two main raw material categories, ecological and conventional. A post hoc test could not be performed here either, as the number of categories (organic and conventional raw material) was less than three. Overall, based on the impact assessments of the previous two raw materials, it can be stated that the use of organic raw materials (since walnut leaves were also organic) had a positive effect on the overall quality of the compost, including the cadmium level [65; 66; 67]. In addition to the abovementioned, the effects of composting time, method, treatment, and raw materials were also examined on other quality characteristics of compost, i.e., AT4 and weed content, but no significant correlation was found, probably due to the low number of items in the sample [68]. Nevertheless, the study is unique because there has never been such a detailed, multi-characteristic compost study in Hungary.