Abstract
Allelochemicals are generally harmful to plant species during one or more of the regeneration phases. This study investigated the influence of biochar in mitigating allelopathic effects of Eucalyptus camaldulensis in plants (Acacia gerrardii and Acacia ampliceps). The seed germination was relatively delayed by dried leaf extract (DLE) on the first day. Both DLE and date palm biochar (DPB) relatively decreased radicle hypocotyl development of both the target species (when compared with the control). In the seedling growth trial, most of the parameters were suppressed by either DLE or DPB. The results revealed that the inhibitory effects of DLE was less pronounced in the case of seed germination when compared with seedling growth. Moreover, any DLE treatments that were mixed with DPB allowed the suppressed plants to develop well. This effect was indicated by the positive value of relative allelopathic effect (RAE). The relative growth rates of seedling height (RGR(H)) varied for the different treatment combinations. Most of the treatment combinations resulted in a higher RGR(H) in test cases than in the control. This study provides meaningful results that support the hypothesis that biochar can be used as an absorptive substance in the immobilization of allelopathic chemicals.