Agaricus bisporus grain spawn substrate with S41 and S44 nutrient supplements

A substrate predominantly composed of mushroom grain spawn and nutrient supplements was tested for Agaricus mushroom productivity with the goal of eliminating composting from mushroom production. Different rates of S41 and S44 mushroom nutrient supplements mixed with grain spawn were used (20%, 15%, 10%, 5%, 1%, and 0%). Two casing treatment were tested for mushroom yield; a non-sterile and a sterile casing with 25% activated carbon. Thiophanate methyl was used in one set of treatments to control the incidence of fungal contamination, whereas another set of treatments had no thiophanate methyl. The results show that mushroom yield from a nonsterile casing overlain on a 10%S41 grain spawn substrate was statistically comparable(p<0.05) to the same substrate with a sterile casing with 25% activated carbon, 6.4 kg/m² and 8.6 kg/m², respectively. Adding thiophanate methyl lowered the yield for both S41 and S44 (p<0.05). The S41 supplement on average produced greater mushroom yield compared to S44 (p<0.04). When perlite was added to the substrate as a water-holding material, the yield was increased greatly, producing 13kg/m² compared to 7.5 kg/m² for the treatment without perlite (p<0.05).