Figure 5: Productivity (ratio of total yield over the duration of the cropping period) for four mushroom species growing on seven cultivation substrates (TPOMW: raw two-phase olive mill waste; cTPOMW: composted two-phase olive mill waste). Values (g days−1) are expressed as means ± standard errors of means, . Lack of letters in common indicates statistically significant differences (Gabriel’s -test, ) among substrates for each species examined.