The Effects Of Various Doses of Vermicompost Solid and Tea Applications on Total Phenolic Content and Some Phenological Parameters of Sweet Basil (Ocimum basilicum L.).

Organic fertilizer application on basil cultivation is highly recommended to preserve its natural aroma and essential oil yield. In this study, 7 doses (0%, 4%, 8%, 12%, 16%, 20%, and 24%) of vermicomposts applied through two different application methods; solid vermicompost (SV) to the root zone and vermicompost tea (VT) as foliar spray. At the end of the 10th week of the vegetational development, some phenological characters including fresh weight, dry weight, plant height and leaf length were recorded and leaves at similar positions of each individual were harvested and then subjected to total phenolic content analysis. According to the results, The highest increase and amount of total phenolic content were determined at the application dose of 24% SV with the rate of 67%. Although, the SV applications increased total phenolic content at the doses of 4%, 8%, 12%, and 24% more than the same doses of VT; the VT application doses of 16% and 20% increased the total phenolic content more than the same doses of SV applications. Despite the highest total phenolic content increase was determined at the 24% SV application group as 67%, there was not a significant decrease in the phenological parameters of this application group when compared with the other SV application doses. Nevertheless, the highest values of phenological parameters and conversely a decrease as -34% in total phenolic content were determined at the highest VT application dose of 24%. The results obtained from the solid vermicompost applicated groups revealed that the 24% SV application induced the total phenolic compound synthesis more than the other application doses without causing a significant decrease in the phenological parameters. Besides, the application of 24% vermicompost tea through foliar spraying decreased the total phenolic compound synthesis and conversely induced biomass production considerably, indicating an inverse relationship between them