Effect of Biofertilizer and Biochar Applications on Quantitative, Qualitative Yields and Root Characteristics of Flue-Cured Tobacco (Nicotiana tobacum L.) Under Dryland Farming Condition

Tobacco is cultivated as a valuable crop in more than one hundred countries in different climatic conditions and plays an important role in the economies of some countries.This study was performed to evaluate the effect of mycorrhiza and azotobacter with application of biocahr on tobacco leaf yield, root characteristics and phytochemical components under rainfed conditions for two growing seasons at 2016 and 2017 at the Research Farm of Tirtash Tobacco Research and Education Center of Mazandaran province, Iran. A factorial experiment based on randomized complete block design with four replications and three treatments was performed. Treatments consisted of biochar (B) at three levels (0, 4 and 8 ton/ha), mycorrhiza (M), and azotobacter (A) both at two levels (without and with application). Application of 4 ton/ha biocahr increased fresh yield by 26%, cured yield 26%, root dry weight 44%, root fresh weigth 37%, root length 41%, nicotine 3%, while reduced sugar content 24% and sugar to nicotine ratio by 21% as compared to zero level of biochar application. The effect of mycorrhiza and azotobacter application on tobacco leaf yield but it was not significant, however, azotobacter had the most significant effect on nicotine content (17%). There was a positive and significant correlation between root characteristics and tobacco leaf yield. Due to the lack of significant differences between levels of 4 and 8 tons per hectare of biochar in most of the evaluated traits in terms of economic approach, the use of 4 tons per hectare of biochar along with mycorrhiza and Azotobacter to reduce the adverse of low water effects in rainfed farms and ameliorate the tobacco growth is recommended. Also azotobacter application is considered as desirable factor to increase of nicotine in tobacco.