Optimization of agro-residues as substrates for Pleurotus pulmonarius production

The "replacing wood by grass" project can partially resolve the conflict between mushroom production and balancing the ecosystem, while promoting agricultural economic sustainability. Pleurotus pulmonarius is an economically important edible and medicinal mushroom, which is traditionally produced using a substrate consisting of sawdust and cottonseed hulls, supplemented with wheat bran. A simplex lattice design was applied to systemically optimize the cultivation of P. pulmonarius using agro-residues as the main substrate to replace sawdust and cottonseed hulls. The effects of differing amounts of wheat straw, corn straw, and soybean straw on the variables of yield, mycelial growth rate, stipe length, pileus length, pileus width, and time to harvest were demonstrated. Results indicated that a mix of wheat straw, corn straw, and soybean straw may have significantly positive effects on each of these variables. The high yield comprehensive formula was then optimized to include 40.4% wheat straw, 20.3% corn straw, 18.3% soybean straw, combined with 20.0% wheat bran, and 1.0% light CaCO₃ (C/N = 42.50). The biological efficiency was 15.2% greater than that of the control. Most encouraging was the indication that the high yield comprehensive formula may shorten the time to reach the reproductive stage by 6 days, compared with the control. Based on the results of this study, agro-residues may be used as a suitable substitution for sawdust and cottonseed hulls as the main cultivation substrates of P. pulmonarius. These results provide a theoretical basis for the "replacing wood by grass" project on edible mushroom cultivation.