Pelletization of soil amendment: Optimizing the production and quality of soil amendment pellets from compost with water and biochar mixtures and their impact on soil properties

Utilizing organic waste to sustain agricultural productivity poses a global challenge. Increasing soil organic carbon through compost-biochar pellets emerges as a promising strategy for sustainable agricultural productivity. Therefore, the objective of this study was to produce soil amendment pellets (SAPs) using various mixtures of compost (cow dung, Albizia saman leaves, Dipterocarpus alatus leaves, and mixed leaves), water (20%, 30%, and 40% by weight), and biochar (0%, 5%, and 10% by weight). When consider individual factor, the results indicate that composted mixed leaves, characterized by small particles and high density, 5% by weight of biochar, and 20% by weight of water significantly improved both the production efficiency and properties of SAPs. An optimal combination effect is observed with A. saman leaves compost, 20% water content, and 5% biochar content. This combination resulted in the highest pelletization rate (244.80 kg hr-1), minimized energy consumption (13.45 kW-hr ton-1), and achieved the highest bulk density (933.33 kg m-3), approximately 2 times increase. When applied to soil, SAPs are viable for ensuring nutrient availability and carbon retention. Moreover, it leads to profound alterations in microbial activity and soil texture. Especially in SAPs, mixing with biochar facilitates the slow release of nutrients. In conclusion, this study demonstrates the successful production of SAPs, offering potential for the organic pelleting industry and highlighting their effectiveness in enhancing soil properties, thus promoting sustainable agriculture.