Abstract: Addressing the challenge of disposing of waste litter from medium and small-scale waterfowl farms, this study focuses on waste bedding generated from fermentation-bed farming systems. A simplified composting experiment with surface mulching was conducted to investigate the effects of mulching on the maturity of the compost and the agronomic efficacy of the resulting compost products. Over a 72-day composting period, discarded bedding from fermentation-bed systems was subjected to three treatments: an uncovered control (UC), coverage with non-woven fabric (NW), and coverage with plastic film (PE). Parameters including temperature, oxygen levels, organic matter degradation, nitrogen retention, and humification dynamics were monitored throughout the composting process. A subsequent field trial evaluated the agronomic performance of substituting varying proportions of chemical fertilizer (CF) with the compost products in perennial ryegrass (Lolium multiflorum) cultivation, assessing biomass yield, plant nutrient uptake, and soil fertility. The results show that both mulched treatments (NW and PE) sustained high-temperature phases (>55 ℃) for 32-42 days, satisfying standard requirements of 7 days for effective composting. NW demonstrated rapid temperature rise and enhanced organic matter decomposition, whereas PE significantly reduced carbon and nitrogen losses and enhanced humification, as indicated by an increase in the humic acid/fulvic acid (HA/FA) ratio. Compost produced under PE coverage retained higher levels of ammonium nitrogen and total humic substances, reflecting more stabilized organic transformation. Results from the field trial revealed that replacing 50% of CF with PE-derived compost achieved biomass yields comparable to those full CF application, while significantly elevating soil organic matter and total nitrogen. However, elevated electrical conductivity (EC) of PE compost raised concerns regarding potential soil salinity, highlighting the need for mitigation strategies in long-term applications. The findings highlight plastic film coverage offers a cost-effective approach to enhance composting efficiency and preserve nutrients, enabling small-scale farms to convert waste bedding into high-quality fertilizer. While 50% substitution of CF with PE compost maintains crop productivity and improved soil fertility. This study provides practical insights for sustainable and low cost waste management and circular agriculture in waterfowl farming systems.