Effects of biochar applications on growth, nutrient content and biochemical properties of Ocimum basilicum L.

This study investigated the effects of biochar treatments on the growth, nutrient content and some biochemical properties of basil. Biochars obtained from two different biomasses, rice husk (RBC) and tomato harvest waste (TBC), were applied at a dose of 2% to the growing medium consisting of a 1 : 1 soil and peat mixture. No biochar-added medium (1 : 1 soil and peat) was used as a control. The experiment was established in a completely randomized design with six replications for each treatment. At the end of the study, the height, number of lateral branches, total herb weight, and leaf weight of the plants were measured. In addition, chlorophyll contents in SPAD (Soil Plant Analysis Development), different nutrients and total phenolics contents, and antioxidant activities were analyzed. As a result of the study, the effects of biochar treatments differed depending on the biomass source. RBC significantly increased plant height, total herb weight, and leaf weight while negatively affecting the number of lateral branches. TCB did not cause any significant variation in plant height and number of lateral branches. While RBC provided a slight increase in leaf weight compared to the control, it did not cause a significant change in plant height, total herb weight, and the number of lateral branches. Except for a slight increase in K content due to RBC application, both biochar treatments did not cause a significant increase in leaf nutrient content. While RBC treatment did not cause a significant change in total phenol, it caused an increase in antioxidant activity. TBC application decreased the SPAD value from 22.4 in the control to 20.4.