Evaluation of local substrates as rice straw alternatives for oyster mushroom (Pleurotus ostreatus) cultivation in resource-constrained Darchula, Nepal

Oyster mushroom cultivation, though cost-effective, faces constraints due to seasonality and substrate availability. An experimental study was conducted in the resource-constrained Darchula district of Nepal from February to May 2022. The aim was to identify and recommend economically sustainable alternatives to rice straw for oyster mushroom production using local substrates in regions with limited resources. Six treatments; rice straw (T1), banana leaves and pseudostem (T2), maize cob (T3), sawdust (T4), grass (Eulaliopsis sp.) (T5), and spent mushroom substrates (T6); were employed in a completely randomized design with four replications. Statistical analysis of growth and yield parameters revealed significant results (P values ranging from P>0.001 to P>0.05) across all parameters. The maize cob treatment exhibited a shorter spawn run period (20.50 days) and the earliest pinhead formation (25 days). The highest total yield (3.14 kg) across three flushes was obtained from paddy straw, followed by T2 and T5, yielding 2.05 kg and 1.43 kg, respectively. Sawdust, despite its larger stalk (1.23 cm) and pileus diameter (7.72 cm), had the lowest production (0.63 kg). Maximum biological efficiency was recorded for T1 (139.63%), followed by T2, T5, and T3, respectively. Economically, T1 resulted in the highest gross margin per 10 kg of substrate (NRs.1845.22) and the highest B:C ratio (2.51), followed by T5 and T2. These findings highlight the promise of locally abundant substrates such as banana leaves, pseudo stems, Eulaliopsis, and maize cobs as economically viable alternatives to rice straw in regions with limited straw availability or unsuitable climates for rice cultivation.