## 4 Discussion
Thus, organic fertilizer production through compost generation plays a significant role in crop production. Being an agriculturally based country, the demand for fertilizer in crop production is huge in Bangladesh. However, farmers tend to prefer chemical fertilizers to compost for high and quick yields. Sometimes, the replacement of chemical fertilizer seems to be very impractical because farmers evaluate compost quality to be very inconsistent and unreliable. Most farmers refuse to use compost consistently because they are more interested in increasing crop yield rapidly without considering the environmental impacts of synthetic fertilizers. Therefore, to extend livestock compost more widely in Bangladesh, further research should be conducted, e.g., using technology to more precisely evaluate compost quality and efficiency in crop yield compared to the results for synthetic fertilizer. Figure 15 illustrates the comparative contribution of different livestock to biogas and compost production. Large animal manure accounts for a significant 88.91% of the total, with cattle manure contributing 83.59%, while buffalo manure only represents 5.31% of the overall biogas production. Poultry manure makes up approximately 9.52% of the total biogas output, although small animals in Bangladesh contribute a minimal percentage to biogas production, which aligns with previous findings [12; 13; 30]. Large animal and poultry manure exhibit the highest potential for biogas or bioenergy generation in rural areas of the country [90]. In addition to the manure potentiality assessment, this study also found that the GHG emissions and manure nutrient leach-out were reduced by producing both biogas and compost, which is encouraged by the existing rules and policies in Bangladesh. Among GHG mitigation options like better storage, separation, aeration of livestock manure, etc., following a potential assessment, it was determined that biogas and compost generation are foremost for providing both socio-economic and environmental benefits. This study estimated the average emission rate from biogas-based electricity generation as 298.21 g CO\({}_{\text{2 eq}}\)/kWh, which was parallel to the results in the studies by Refs. [91; 92; 93; 94]. Some studies found lower GHG emissions (9-25 g CO\({}_{\text{2 eq}}\)/kWh) [22; 95] and higher GHG emission (510 g CO\({}_{\text{2 eq}}\)/kWh) [21] than those observed in this study because of the different methodological approaches and equations applied. However, it is supported that the \begin{table}
\begin{tabular}{c c c c c c c c} \hline
**Manure Potentiality** & **Cattle** & **Buffalo** & **Goats** & **Sheep** & **Chickens** & **Ducks** & **Total** \\ \hline Manure generation (million & 188.819 & 11.528 & 8.618 & 1.208 & 5.645 & 1.156 & 216.98 \\ tons/year) & 94.409 & 5.764 & 1.120 & 0.157 & 5.081 & 1.04 & 107.57 \\ Biogas (million m\({}^{3}\)/year) & 12,847.06 & 784.36 & 101.64 & 14.24 & 1069.33 & 218.96 & 15,035.59 \\ Electricity (MWh/year) & 23.12 & 1.41 & 0.202 & 0.028 & 1.924 & 0.394 & 27.064 \\ Biofertilizer (kilotons/year) & 12,273.26 & 749.33 & 104.86 & 14.69 & 294.68 & 60.34 & 13,497.17 \\ Compost (kilotons/year) & 58,534.03 & 3573.72 & 717.02 & 100.47 & 3759.76 & 769.86 & 67,363.03 \\ Synthetic fertilizer supply & 692.81 & 43.24 & 643.78 & 90.21 & 609.28 & 125.76 & 2202.13 \\ (kilotons/year) & & & & & & & \\ \hline \end{tabular}
\end{table} 
Table 7: The assessed livestock manure potential in Bangladesh in 2024. GHG emission from biogas-based electricity generation is lower than the emission from electricity production using resources such as fossil fuels, coal, etc. other than biogas sources in Bangladesh, i.e., 588 g CO\({}_{2}\)eq/kWh [96]. The study also estimated the GHG emission reduction potential for compost, which is comparatively higher than that for biogas generation due to the fact that it requires less fuel consumption and operational costs [97].