|Brauer, David - Dave|
Submitted to: Journal of Sustainable Agriculture
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/15/2002
Publication Date: 10/1/2003
Citation: KIMMONS, T.E., PHILLIPS, M., BRAUER, D.K. 2003. SMALL FARM SCALE PRODUCTION OF AEROBIC COMPOST FROM HARDWOODS PREDIGESTED BY LENTINULA EDODES. JOURNAL OF SUSTAINABLE AGRICULTURE. 23(1):109-123. Interpretive Summary: Shiitake mushroom production in the United States has expanded greatly in recent years. Log-grown shiitake mushrooms tend to be organically grown and command premium prices. A modest shiitake operation will produce a considerable volume of spent logs in a year, about 10 cubic meters of materials per $10,000 of sales. There is no valuable use for these spent logs at present. Composting spent logs may be one way of generating value from this waste product. Technology appropriate for composting the volume of material produced by a shiitake operation may not be readily available. Compost research has been conducted for either household use or industrial/municipal users. Research results for a scale between these two extremes are lacking. The ability of 4 methods to produce compost from chipped spent shiitake logs was tested. Both passively aerated static pile and actively aerated static pile methods were able to efficient produce compost from spent shiitake logs. These results are of interest to log-grown shiitake producers and land resource professional who work with these producers.
Technical Abstract: The shiitake mushroom industry produces a waste product in the form of spent hardwood logs that have been partially digested by the lignicolous fungi, Lentinula edodes. At present there is no economically viable mechanism for disposal of these logs. The objectives of this research were to test several methods of composting chipped shiitake logs that may be appropriate for small farms and to evaluate the use of the compost material as a source of nutrients for plant growth. Four methods for producing compost from spent shiitake logs were compared: a) in-vessel tumbler; b) wire mesh cage; c) passively aerated static pile; and d) actively aerated static pile. Compost was produced from a mixture of 85% chipped spent shiitake logs and 15% grass clippings with N added as urea to yield an approximate C to N ratio of 30 to 1. In terms of ease, scale and cost of production both of the aerated static pile methods were superior to the other two methods. The resulting compost contained relatively high concentrations of Ca and low concentrations of P. Composting of chipped shiitake logs increased total and alive fungal constituents relative to bacterial populations. The ability of the compost to supply N to growing crops was assessed by amending soils for production of spinach in the greenhouse. Compost additions increased the growth of spinach without increasing soil nitrate-nitrogen levels. These results indicate that spent shiitake logs can be converted into compost by methods appropriate for small farms and that the resulting compost can be used to stimulate crop growth.