Volume 16 Part 1 Article 2
Title: Organic Matter Transformations in Compost During Mushroom Cropping and Postcrop Weathering
Authors: B. Chefetz and P.G. Hatcher
Improving the process of mushroom composting is of importance in order to provide an optimal growing medium for the production of mushrooms. Since composting produces a food source for the mushrooms, the compositional changes of the compost occurring during the cropping of Agaricus bisporus were studied. Polysaccharides were the main fraction degraded (or utilized by the mushroom) during the cropping period. Lignin alteration primarily involved a preferential degradation of syringyl units and oxidation of side chains of guaiacyl moieties. Spent mushroom substrate (SMS) was studied in an effort to better understand the chemical properties and transformations of organic matter that occur during the weathering process in the field. In this study, SMS was piled (20-m x 6-m x 1.5-m in height) in an open field and weathered for 15 months. Using several analytical techniques, chemical properties of the substrate collected from the top and bottom parts of the weathering pile were studied. The data suggested that weathered SMS from the top of the pile degraded rapidly; the relative level of polysaccharides decreased by 33%, while the level of aromatic C increased by 21% during the process. Lignin-derived products indicated that preferential degradation of syringyl units and oxidation of Ca-Cb bonds occurred in the SMS at the top of the pile. In contrast, no major changes in lignin-derived structures were observed in the SMS from the bottom of the pile. Decomposition at the bottom of the pile was significantly slower, probably due to the lack of oxygen.Please login to download the PDF for this proceeding.