Effect of Palm Leaf Biochar and Water Stress on some Morphological Characteristics and Micronutrients Concentration of Holy Basil

Water stress is one of the most important growth limiting factors of plants and the most common environmental stress. An experiment was conducted as a factorial design in a completely randomized design with three replications to study the effect of palm leaf biochar and water stress on morphological characteristics and micronutrients concentration of holy basil plant. Treatments consisted of three water levels [100% field capacity (without stress), 75 and 55% field capacity] and three biochar levels (0, 2 and 4% by weight). Results showed that the application of 75 and 55% of the field capacity decreased 6.6% and 19.2% of plant height, 13.8% and 38% fresh weight and 8% and 20% dry weight, respectively, as compared with control,. However, in 55% of the field capacity, SPAD index significantly increased by 18.8%. With application of water stresses, the concentration of zinc and copper decreased, but iron and manganese significantly increased as compared to the control. Addition of 2% of palm leaf biochar significantly increased the iron and manganese concentration in the holy basil by about 26 and 11.7%, respectively, as compared with control.