A. Noroozi - Department of Agrotechnology, Faculty of Agriculture, Ferdowsi University of Mashhad, P. O. Box: ۹۱۷۷۹ ۴۸۹۷۴, Mashhad, Islamic Republic of Iran.
P. Rezvani Moghaddam - Department of Agrotechnology, Faculty of Agriculture, Ferdowsi University of Mashhad, P. O. Box: ۹۱۷۷۹ ۴۸۹۷۴, Mashhad, Islamic Republic of Iran.
M. Hashemian - Department of Chemistry, Faculty of Sciences, Ferdowsi University of Mashhad, Mashhad, Islamic Republic of Iran.
S. Khorramdel - Department of Agrotechnology, Faculty of Agriculture, Ferdowsi University of Mashhad, P. O. Box: ۹۱۷۷۹ ۴۸۹۷۴, Mashhad, Islamic Republic of Iran.

Three different levels of biochar addition in soil (۰, ۱, ۲ kg m-۲) and simultaneous irrigation treatments (۵۰, ۸۵, and ۱۲۰% of crop Evapotranspiration (ETc)) were applied to basil (Ocimum basilicum L.) for two consecutive years (۲۰۱۸ and ۲۰۱۹). Central Composite Design (CCD) was used as an experimental optimization method, and ۱۳ given experiments were carried out. The study was performed at the research farm of the Ferdowsi University of Mashhad, Iran. The effects of these treatments were evaluated on biochemical attributes (total chlorophyll, total phenol, and total soluble carbohydrates) and morphological criteria (biological yield, height, seed yield, and harvest index). Then, all the results were statistically analyzed. The results revealed that biochar amendment in the soil decreased all examined biochemical characteristics. Meanwhile, biochar in the soil strengthened the morphological properties of the basil plant. Also, the basil plant significantly responded to the amount of irrigation levels. High levels of water treatments reduced total phenol and total soluble carbohydrates and raised all other measured factors. Statistical analysis shows no significant relationship between ۲-way-interaction (biochar×irrigation) and measured factors, except total soluble carbohydrates.

Biological yield, Chlorophyll, Crop evapotranspiration, Harvest Index, Total soluble carbohydrates.