An insight into herbicidal properties of Ocimum leaf and oil-loaded biochar formulations

The replacement of synthetic herbicides with natural herbicides is a good option for sustainable agriculture. The use of suitable and sustainable carriers for these natural further enhanced their life span and effectiveness. The present study examined Ocimum dry leaf powder and oil-loaded biochar formulations for the sustained release of phenolics and oil constituents and herbicidal activities. The characterization of formulations using FTIR, SEM, GC, and HPLC demonstrated the loading of phenolics and the incorporation of linalool and methyl chavicol in dry leaf powder and oil-loaded biochar formulations, respectively. The release of phenolics, linalool, and methyl chavicol was observed from different formulations which followed Fickian diffusion. They displayed an inhibitory effect on C. rotundus. In the field experiment, formulation demonstrated toxicity on weeds C. rotundus, A. arvensis, C. album, A. viridis, D. sanguinlis, G. pensylvanica, and S. arvensis with reduction in population (38-100%) and growth (33-100%). Formulations based on Ocimum basilicum. L was more effective as compared with Ocimum sanctum. L in most of the weeds. Formulations showed more toxicity on A. arvensis and less inhibitory effect on D. sanguinlis as compared with other weeds. The disruption in the membrane integrity and impairment in plant metabolism could be the major mechanism for the herbicidal activities of the formulation.