The use of un-composted spent mushroom residue as a replacement of peat in substrates for Gossypium herbaceum and Talinum paniculatum

Abstract

In order to evaluate the effect of growing media with peat and spent mushroom residue (SMR) on medicinal plants, we cultured Gossypium herbaceum and Talinum paniculatum seedlings in the substrates with SMR in proportions of 0% (control), 25%, 50%, 75%, and 100%. Results showed that G. herbaceum seedlings can survive in all treatments, but T. paniculatum seedlings died out in 75% and 100% SMR substrates where higher electrical conductance was found (2.3-2.7 dS m-1). Both growth and biomass mostly declined with the increase of SMR proportion in the growing media for the two species except for root biomass in T. paniculatum seedlings between the control and the 25% SMR treatment. Shoot nitrogen (N) and phosphorus (P) concentrations and contents tended to be higher in low- and high-SMR-proportional substrates, respectively. N and P statuses were both diagnosed to be excessive than needed for the two species. Overall, it was not recommended to culture G. herbaceum seedlings in the substrates with SMR; instead T. paniculatum seedlings can be cultured in the growing media with SMR in volumetric proportion of 25%.