Edible mushrooms: from industrial cultivation to collection from the wild

Abstract

INTRODUCTION The domestication and agronomical production of edible mushrooms has a relatively short history compared to that of staple crops and of many vegetables and fruits (Janick, 2005). A method for the cultivation of a Chinese mushroom, shiitake, Lentinula edodes, is known from 1313 AD (Wang, 1987). The cultivation of the white button mushroom, Agaricus bisporus, was described for the first time by Tournefort (1707). All edible mushroom species that can be cultivated in a system comparable to the industrial cultivation of the white button mushroom are saprobic, being able to use dead organic matter for their growth. Boa (2004) estimates the number of saprobic species that can be cultivated as almost 100. Several valuable edible fungi, in particular ectomycorrhizal species like truffles (Tuber magnatum and Tricholoma melanosporum), matsutake (Tricholoma matsutake), kings boletes (Boletus edulis), and chanterelles (Cantharellus cibarius) cannot yet be produced agronomically. At best, semi-natural cultivation systems (e.g., truffle orchards) have been developed (Hall et al., 2003a). INDUSTRIAL CULTIVATION OF WHITE BUTTON MUSHROOMS, AGARICUS BISPORUS White button mushrooms require two substrates for cultivation. A layer of compostnourishes the mycelium and a layer of casing soil covers the compost allowing the mycelium to form fruit bodies. Compost production and the cultivation process have been described in various handbooks (Flegg et al., 1985; van Griensven, 1988; Oei and Maas, 2003; Chang and Miles, 2004). China, the U.S.A. and The Netherlands are the most important producers of white button mushrooms. Productions in these countries are, respectively, 600, 380 and 260 x 103 tonnes annually; the statistics from China need to be taken with caution. The following key data characterize the mushroom industry in the Netherlands. Almost 400 kg of mushrooms can be produced per tonne of full grown compost; this amount of compost being filled on a surface area of about 10 m2. The amounts of “full grown compost” and of “casing soil” used annually are about 700 and 380 x 103 tonnes. Due to the short growing cycle, about eight crops of mushrooms per year can be grown in a cultivation room. The net surface area for mushroom growing is over 100 ha. The rest-product of mushroom cultivation is called “spent mushroom substrate,” SMS. The amount of SMS produced is about 850 x 103 tonnes; this is marketed as a fertilizer in horticultural crops. The number of full-time jobs in primary production is currently about 5000. Key data for the Netherlands may be extrapolated to other countries, although compost-to-mushroom conversion and labour efficiency are considerably lower.