Influence of enriched spent button mushroom substrate on growth and yield of onion (Allium cepa L.)

Spent mushroom substrate (SMS) is a major by-product of mushroom cultivation and is generated in large quantities. It contains considerable organic matter and nutrients and can be utilized as an organic amendment for improving soil fertility and crop performance. Application of SMS can improve soil physical properties, nutrient availability and beneficial microbial activity. Enrichment of SMS with beneficial microorganisms such as Azotobacter, phosphate-solubilizing bacteria (PSB) and potassium-mobilizing bacteria (KMB) may further enhance nutrient transformation and availability in soil, thereby promoting plant growth and reducing disease development. In view of this, the present investigation entitled “Influence of Enriched Spent Button Mushroom Substrate on Diseases and Yield of Onion (Allium cepa L.)” was conducted at the experimental field of the Plant Pathology Section, Govt. College of Agriculture, Pune, during the Rabi season of 2025. The study was undertaken to evaluate the effect of enriched spent button mushroom substrate on growth and yield of onion. Application of different treatments significantly influenced the growth and yield of onion crop. Among all the treatments, T4 (SMS + Consortium of Azotobacter + PSB + KMB) recorded the highest plant height of 31.20, 46.93, 53.26 and 52.46 cm and leaf length of 29.30, 45.66, 51.30 and 49.16 cm at 30, 45, 60 DAT and harvest, respectively. T4 also recorded the maximum polar bulb diameter (6.93 cm), equatorial bulb diameter (7.00 cm), fresh weight (126.66 g), dry weight (19.00 g) and bulb yield (16.06 kg/plot and 49.56 t/ha). In comparison, the absolute control (T9) recorded the lowest values for these parameters. Overall, T4 (SMS + Consortium of Azotobacter + PSB + KMB) was significantly superior over the other treatments, followed by T5 (FYM + Consortium of Azotobacter + PSB + KMB), and proved most effective in enhancing growth and yield of onion crop. The study indicated that enrichment of spent button mushroom substrate with beneficial microorganisms can serve as a sustainable approach for improving onion productivity and soil fertility.