# Farmed Insect Frass as a Future Organic Fertilizer
## 3 Results and Discussion
### Quantitative Assessment of Groups of Functional Microorganisms  
The incubation of acid peat with different fertilizers and N rates resulted in significant variations in environmental functional gene loads (Table 5). The abundance of total fungi increased significantly in peat treated with frass at lower N rates (F50 and F100 mg dm\({}^{-3}\)) but decreased at higher N rates (F200 and F400). _Clostridium_ spp. counts decreased significantly following the application of F400. The incubation time influenced _Pseudomonas_ spp. counts, with a significant decrease noted in frass treatments (F100, F200, and F400). The _chiA_ gene load increased significantly in F50, F200, F400, U50, and U400 treatments. The _nifH_ gene load increased significantly only with urea at the highest N rate. In contrast, the _nosZ_ gene load decreased in peat incubated with frass in treatment F100. The _amoA_ gene load significantly decreased in treatments F100, F200, F400, U100, U200, and U400, while the _ureC_ gene load was significantly lower after applying lower frass rates (F50 and F100) compared with the baseline. Functional gene loads in incubated acid peat were influenced by the type of fertilizer and the N rate (Table 6). Total bacterial load was significantly higher after frass application than urea, peaking in F100 and F50 treatments and decreasing in F400. Total fungal load was significantly higher in peat incubated with frass than urea. The load of _Clostridium_ spp. increased significantly only in response to the highest N rate. Frass applied at the lowest rate inhibited the growth of _Clostridium_, but the load increased significantly in F200 and reached the highest value in F400. Peat fertilization with urea at U50, U100, and U400 contributed to a significant increase in the load of _Clostridium_ spp. The load of _Pseudomonas_ spp. varied significantly with different N rates and fertilizer types. _Bacillus_ spp. load decreased significantly after applying low N rates (50 and 100 mg dm\({}^{-3}\)) and reached the control treatment level at the highest N rate (400 mg dm\({}^{-3}\)). The abundance of _Bacillus_ spp. in peat fertilized with urea at U50 to U200 was significantly higher than that in peat fertilized with frass, while frass showed a more beneficial effect at the highest rate. The _chiA_ gene load was significantly lower in peat fertilized with all N rates compared with the control treatment. Frass at F100 (_p_ < 0.01) and urea at U50 and U200 (_p_ < 0.05) increased the abundance of chitinolytic bacteria. Irrespective of the applied fertilizer, increasing N rates (50, 200, and 400 mg dm\({}^{-3}\)) led to a significant decrease in the number of _nifH_ gene copies. The abundance of both _nifH_ and _nosZ_ genes increased significantly (_p_ < 0.0001) after applying frass compared with urea. Frass at F50 and F100 contributed to a significant increase in the number of _nifH_ gene copies, relative to the control treatment. The abundance of the _nifH_ gene was higher in peat fertilized with N at 50, 100, and 400 mg dm\({}^{-3}\) than in the control treatment, whereas the 200 mg N dm\({}^{-3}\) rate significantly decreased its abundance. The abundance of the _nosZ_ gene increased after applying frass at all N rates compared with urea (minimum \(p\) < 0.001). However, frass rates of F50-F200 increased the abundance of the  
\begin{table}
\begin{tabular}{c c c c c c c c c c c} \hline \hline
**Fertilizer** & \begin{tabular}{c} **Total** \\ **Bacteria** \\ \end{tabular}  & \begin{tabular}{c} **Total** \\ **Fungi** \\ \end{tabular}  & \begin{tabular}{c} _Clostridium_ \\ **spp.** \\ \end{tabular}  & \begin{tabular}{c} _Pseudomonas_ \\ **spp.** \\ \end{tabular}  & \begin{tabular}{c} _Bacillus_ \\ **spp.** \\ \end{tabular}  & \ \begin{tabular}{c} _chiA_ \\ \end{tabular}  & _nifH_ & _nosZ_ & _amoA_ & _ureC_ \\ \hline \begin{tabular}{c} Baseline \\ (mean log\({}_{10}\)) \\ \end{tabular}