Evaluation of casing materials made from spent mushroom substrate and coconut fibre pith for use in production of Agaricus bisporus (Lange) Imbach

Abstract

The agronomic performance of different proportions of mixtures of coconut fibre (CF) pith and spent mushroom substrate (SMS) was studied for their use as casing material in mushroom cultivation. After chemical and biological characterisation of the casing substrates qualitative and quantitative production parameters were evaluated in a cycle of Agaricus production. An increase in the proportion of SMS reduced the number of carpophores and overall yield; while the first flush was delayed, mushroom size tended to increase and the mushrooms had a higher dry matter content and a better texture, although their colour was worse. Combinations of CF pith and SMS of 4:1 and 3:2 (v/v) gave biological efficiencies of 92.9 and 82.6 kg/100 kg compost, respectively. These values compare well with that obtained from the commercial casings used as a control. The high electrical conductivity of the mixture containing the highest proportion of SMS would limit its use. However, the results indicate the viability of reusing SMS as an ingredient of casing material for mushroom cultivation. This alternative could be considered to partially replace the organic substrates normally used for mushroom cultivation, with the double advantage of decreasing cost and reducing the environmental impact of waste disposal.