Optimizing the C/N ratio in composting fresh coconut husk and shell waste for organic fertilizer production

Abstract The Mekong Delta region produces significant organic by-products from agriculture, which can cause environmental pollution and infectious diseases. However, these by-products can be recycled into valuable raw materials for organic fertilizers. This study aims to create an organic substrate from fresh coconut husks and waste shells, reducing waste and maximizing the value of these materials. By determining the nutritional properties of shells and coconut husks, the study calculates the optimal mixing ratio with substrates and additional fertilizers to achieve a suitable C/N ratio for composting. The decomposition process is monitored over 45 days, tracking pH, temperature, total aerobic microorganisms, cellulose-decomposing microorganisms, and pathogenic E. coli - Coliform . Post-decomposition, the treatments are evaluated for organic matter content, total nitrogen, and phosphorus, and compared with the organic fertilizer standard QCVN 01 - 189:2019/BNNPTNT. Preliminary results show effective decomposition from day 6, with temperatures exceeding 50°C. Most final compost samples meet quality standards for organic and microbial fertilizers and show promising results in mustard greens trials. Thus, the fresh coconut husk and shell powder mixture has the potential to produce optimal compost, effectively recycling these materials.