Yield and chemical composition of oriental tobacco as affected by biostimulant application

Radka Bozhinova

Abstract: Biostimulants have been identified as an alternative to chemical fertilizer to increase crop production in sustainable farming. The aim of the study was to investigate the effects of two commercial biostimulants (protein hydrolysate (PH) Trainer® and microbial inoculant Europlus®) on the growth, yield and quality of oriental tobacco. The field experiment was conducted in 2020 and 2021 at Tobacco and Tobacco Products Institute, Markovo, Bulgaria on Rendzic Leptosol. The experimental design was a randomized complete block replicated three times. The doses of both biostimulants were used based on the manufacturer’s recommendations. The plants were sprayed two times with PH Trainer four and six weeks after transplanting. The microbial product Europlus was incorporated in the top soil layer three weeks after transplanting. The control plants were not treated with biostimulants. The application of microbial inoculant Europlus and PH Trainer improved the yield of tobacco by 5.5% and 6.7%, respectively, in comparison with untreated plants. The enhancement of the yield of sun-cured leaves was mainly due to the higher leaf area. Biostimulant treatments had no significant effect on macro and micronutrient concentrations in tobacco leaves. The application of PH Trainer and microbial inoculant Europlus increased the N, P, and K concentrations in leaves. The concentration of Ca, Mn, Zn and Cu were slightly higher than the control treatment when microbial inoculant Europlus was applied. The addition of protein hydrolysate Trainer and microbial inoculant Europlus increased nicotine content by 13.5% and 8.6%, respectively, compared to the control. The reducing sugars/nicotine ratio was better in tobacco from treatments with biostimulants compared to non- treated control. The results indicated that the use of biostimulants (microbial inoculant and protein hydrolysate) in sustainable tobacco farming was effective in increasing the yield of oriental tobacco and the quality of cured leaves.

Keywords: chemical constituents; growth parameters; macronutrients; microbial inoculant; micronutrients; protein hydrolysate; tobacco; yield

Date published: 2023-02-23