Effects of biofertilizers on the growth, physiological parameters, and essential oil content of basil (Ocimum basilicum L.)

Abstract

Basil (Ocimum basilicum L.) is one of the widely cultivated medicinal crops that is used as kitchen herb, vegetables, spice, and especially its essential oil and extracts as therapeutics. One of the promising methods to improve basil growth, yield, and essential oil is use of biofertilizers. In this study, we compared three treatments (methionine, humic acid, and nitroxin) arranged as 2*2*3 factorial based on completely randomized design with three replicates. All treatments significantly increased basil growth parameters, physiological traits, and content of essential oil (P < 0.05). Based on our results, the best and highest amount of parameters (plant height, number of leaves, leaf length, number of branch, dry weight, shoot diameter, root length, plant biomass, chlorophyll b, total chlorophyll, SPAD index, and essential oil) was observed in plants treated with 1 l/ha of methionine*5 l/ha of humic acid*3 l/ha of nitroxin (P ≤ 0.05). In terms of root dry weight and chlorophyll a, the best mean was observed in plants treated with the mixture of 1 l/ha of methionine*5 l/ha of humic acid and the mixture of 5 l/ha of humic acid*3 l/ha of nitroxin (P ≤ 0.05). Especially for content of essential oil (shoots and leaves), plants treated with 1 l/ha of methionine*5 l/ha of humic acid*3 l/ha of nitroxin showed +2.5-fold increase compared to control plants. In conclusion, results of this research suggest that the combination of methionine*humic acid*nitroxin could be an efficient and promising biofertilizers to improve the growth of basil, especially its essential oil.