Yield, size, and mushroom solids content of Agaricus bisporus produced on non-composted substrate and spent mushroom compost

Abstract

Three crops of Agaricus bisporus were grown on non-composted substrate (NCS), spent mushroom compost (SMC), a 50/50 mixture of NSC/SMC, or pasteurized Phase II compost. NCS consisted of oak sawdust (28% oven dry wt), millet (29%), rye (8%), peat (8%), ground alfalfa (4%), ground soybean (4%), wheat bran (9%) and CaCO3 (10%). Substrates were non-supplemented or supplemented with Target® (a commercial delayed release nutrient for mushroom culture) or soybean meal at spawning or casing, or with Micromax® (a mixture of nine micronutrients) at spawning. Mushroom yield (27.2 kg/m2) was greatest on a 50/50 mixture of NCS/SMC supplemented with 10% (dry wt) Target® at casing. The same substrate supplemented with Target® at spawning yielded 20.1 kg/m2. By comparison, mushroom yield on Phase II compost supplemented at casing or at spawning with Target® was 21.6 kg/m2 and 20.6 kg/m2, respectively. On NCS amended with 0.74% or 0.9% Micromax® at spawning, yields increased by 51.8% (12.9 kg/m2) and 71.8% (14.6 kg/m2), respectively, over non-amended NCS (8.5 kg/m2). Conversely, mushroom yields were not affected when Micromax® was added to a 50/50 mixture of NCS/SMC. Mushroom solids content was higher in mushrooms harvested from NCS amended with 0.74% Micromax® (9.6%) compared to non-amended NCS (8.3%).