Volume 17 Part 1 Article 19: Measuring and Iimproving the Rate of Spawn-Running in Compost

Volume 17 Part 1 Article 19
Year 2008
Title: Measuring and Iimproving the Rate of Spawn-Running in Compost
Authors: R. Noble, A. Dobrovin-Pennington, M. Kilpatrick, G. Lyons and H.S. Shekhar Sharma


Due to shorter production cycles, there has been move away from using pasteurised (phase II) compost in cropping rooms to using colonised (spawn-run or phase III) compost. Processing time is a major factor influencing the cost of phase III compost; in particular, colonisation of the compost with mushroom mycelium in expensive spawn-running facilities. To produce phase III compost efficiently, the progress of mycelial growth needs to be measured. The work reported was aimed at developing a method for measuring mycelium in compost and identifying factors that influence the mycelial colonisation of compost, in order to reduce spawn-running time.

Pasteurised compost was obtained from 11 different commercial composting sites on two separate occasions. Experimental composts were prepared at Warwick HRI using different sources of wheat straw and nitrogen. Compost temperatures were not a reliable indicator of mycelial activity. Fall in compost pH, caused by the production of oxalate by mycelium, and increase in laccase, an enzyme produced by mycelium, were good indicators of the rate of spawn-run in compost. Both measurements related to the final mushroom yield from the compost. Increased compaction of compost retarded spawn-running and reduced mushroom yield. A higher spawn rate (0.8% w/w) resulted in greater laccase content, greater compost pH drop and higher mushroom yield than did a lower rate (0.5% w/w). None of supplements used at spawning had a significant effect on spawn-running (except for an early increase in compost temperature) or mushroom yield.

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