Transformation of pellet-based planting media as an organic matter and nutrient enhancer for improving soil quality

Soil degradation driven by excessive inorganic fertilizer use and conventional cultivation practices has reduced land productivity in tropical regions, including Indonesia. This study developed biological pellet-based planting media to improve soil physical, chemical, and biological properties while providing controlled nutrient release. The research employed a panel design and split-plot layout on sandy Entisol soils, evaluating physical–chemical characteristics, rhizosphere microbial colonization, and nutrient-release kinetics using the Gompertz model. The results show that pellets increased soil porosity up to 56%, extended water retention to 22 hours, and significantly enhanced organic carbon as well as N, P, K, Ca, and Mg levels compared with the control. Nutrient release followed a lag–exponential–plateau pattern, indicating an efficient gradual-release mechanism. Microbial and soil-fauna activity more than doubled, demonstrating restored biological functioning of the soil. Treatments with a balanced organic–inorganic ratio (50:50) exhibited the best overall performance across all parameters. Overall, pellet-based planting media prove effective as multifunctional soil conditioners that enhance fertility, nutrient efficiency, and agroecosystem sustainability in marginal tropical soils.