Optimizing Biochar Applications for Improved Growth and Nutritional Quality of Basil Plants Using Rice and Corn Biochars

The study aimed to determine the effects of biochar obtained from rice husk and corn harvest residues on the growth, nutritional content and some biochemical properties of basil plants. Both biochars were applied by mixing them into potting soil at 2% and 5% rates. To determine the effect of applications on plant development, the height and weight of plants and leaf weights, and number of side branches were recorded. Additionally, chlorophyll content (SPAD), phenol content, antioxidant content and P, Mg, Ca, K, S, Fe, Zn, Mn, Cu and B concentrations in the leaves were determined. Compared to the control, significant increases were detected in the leaf weights, height and weights of the plants grown in all pots containing biochar. The highest plants were obtained from 5% rice biochar (RB5) treatment. The highest leaf weight and the highest number of side branches were also observed. in the RB5 treatment. Leaf K contents in RB5 and maize harvest residue biochar (CB) treatments were higher compared to the control. Leaf B, Fe and Mn contents were lower in certain biochar treatments than the control. Biochar applications did not cause a significant change in the antioxidant and chlorophyll content of basil plants. The total phenolic content significantly increased only in RB5 treatment. The effect of biochar application varied depending on the application rate and the properties of the biomass from which the biochar was obtained. Therefore, it is not possible to draw a general conclusion about the effects of biochar applications on plant growth. Contradictory results can be obtained depending on the type of plants and biochars and the characteristics of the growth medium.