Substrate usage and odours in mushroom composting

Abstract

Odour problems associated with producing a composted substrate for mushroom culture were considered at 9 Australian farms, in relation to composting batch recipes. Effects of usage of nutrient rich composting activators were evaluated using nitrogen (N) concentration ratios (%) and a novel ratio, the C/A ratio as indicators of compost nutritional status. The CIA ratio segregated composting ingredients into nutritional classes. Both % N and the C/A ratio showed that excess nutrient usage was positively correlated with odours. Both correlations were significant at P= 0.01. Final % N, however, did not increase with higher initial % N values. This investigation indicates that reducing excessive initial concentrations of available nutrients in compost formulations can reduce odours, while not necessarily reducing compost quality in terms of final N level.