Jamal-Ali Olfati - Department of Horticulture, Faculty of Agriculture, University of Guilan, Guilan, I.R. Iran
F. Rasouli - Department of Horticulture, Faculty of Agriculture, University of Guilan, Guilan, I.R. Iran

ABSTRACT- Almost all oyster mushroom producers in Iran produce this kind of mushroom without any kind of casing soil. Although different kinds of casing soils are available for Agaricus bisporus, limited information is available regarding Pleurotus ostreatus. Availability of peat in many regions around the world is a concern and some researchers' efforts have been devoted to a search for alternative materials which may be used as a substitute or as a combination with peat. This project was undertaken to determine whether vermicompost can be used as a casing soil for oyster mushroom cultivation when cultivated in bins. As a completely randomized experimental design with ۳ replications, this study was accomplished with different casing materials including vermicompost+ peat (۱۰۰:۰, ۷۵:۲۵, ۵۰:۵۰, ۲۵:۷۵, ۰:۱۰۰ v/v) and leached vermicompost +Peat (۱۰۰:۰, ۷۵:۲۵, ۵۰:۵۰, ۲۵:۷۵, ۰:۱۰۰ v/v) effects with control (without casing). Results showed when leached vermicompostwas added to the oyster casing material, the biological efficiency (BE) in the second flush and the percentage of mushroom dry mater (DM) were increased. The highest BE in the second flush (۴۰%) was observed for cased substrate with ۱۰۰% leached vermicompost, while the lowest BE (۹%) showed the control. Percentage of DM was higher in control (۳.۴۴%) compared to cased treatments (۱.۶۵–۳.۲۹%). The BE was higher than ۱۰۰% for treatment cased with leached vermicompost. Overall, total BE for treatments cased with leached vermicompost increased by ۱۸۵% over non-cased treatment. Therefore, considering the fact that using casing for P. ostreatus production is a relatively easy and low-cost cultural practice yielding successful results, it can be used to enhance BE and maximize substrate utilization.

Keywords:, Pleurotus ostreatus, Peat, Vermicompost, Biological efficiency