A Comparison of Static Aeration and Conventional Turning Windrow Techniques: Physicochemical and Microbial Dynamics in Wine Residue Composting

Chile, one of the top global wine producers, produces a significant quantity of grape pomace waste, composed primarily of peels and seeds, of which their management includes many environmental challenges. Composting offers a sustainable waste management solution, converting organic waste into a rich nutrient and beneficial microorganisms for soil amendment. This study compared traditional turning and static forced aeration composting systems using a mix of grape pomace (70 m3), wheat straw (15 m3), and manure (15 m3). The results show no significant differences in the final compost chemical quality between the two systems. Nevertheless, forced aeration (T1) influenced the bacterial community, particularly during the thermophilic stage, leading to a major differentiation compared to traditional composting (T0). Similar Shannon index values for bacterial diversity across stages suggest that both composting methods support comparable levels of bacterial diversity. However, the fungal communities exhibited more variability, likely due to the differences in temperature and aeration conditions between the windrows, which are known to affect fungal growth and activity. While both composting methods met the Chilean regulatory standards and achieved high-quality compost, the forced aeration system demonstrated advantages in temperature control, microbial diversity, and pathogen suppression, suggesting its potential for more efficient composting in similar agricultural contexts.