Comparative effects of bio-inoculant on nutrient dynamics of biodegradable waste

This study evaluated the effects of four bio-inoculants—Fish Amino Acid (FAA), Fermented Plant Juice (FPJ), Indigenous Microorganisms (IMO), and Trichoderma—on nutrient dynamics in compost produced from biodegradable fruit and vegetable wastes. A Completely Randomized Design consisting of a control and four bio-inoculant treatments was employed, and the resulting composts were analyzed for total nitrogen (TN), total phosphorus (TP), and total potassium (TK) after a three-month composting period. Analysis of variance showed that TN was not significantly affected by bio-inoculant application (p = 0.0812), whereas TP (p = 0.0192) and TK (p = 0.0000) differed significantly among treatments. TN concentrations increased in all inoculated treatments compared with the control, with the highest values observed in indigenous microorganisms (3.36%) and fish amino acid (3.34%) treatments. In contrast, TP and TK concentrations were generally higher in the control treatment and lower in the inoculated composts. The lowest TK concentration was recorded in the Trichoderma-treated compost, indicating substantial microbial assimilation associated with enhanced enzymatic activity. The results suggest that bio-inoculants primarily influence nutrient transformation and microbial-mediated nutrient cycling rather than increasing the total nutrient content of compost. Nitrogen remained relatively stable across treatments, while phosphorus and potassium were more responsive to the type of bio-inoculant applied. These findings demonstrate the importance of considering nutrient dynamics and microbial processes, in addition to conventional indicators such as mass reduction, when evaluating compost quality.