Influence of Vermicompost and Bacillus subtilis on the Vegetative Characteristics of Local Grapevine (Vitis vinifera L.) Seedlings

Abstract

The study was carried out in 2025 on a vine nursery in a greenhouse at the Northern Technical University, Technical Agricultural College, Iraq, where the impact of the use of vermicompost and Bacillus subtilis on the vegetative growth of local ‘Zark' grapevines (Vitis vinifera L.) transplants was evaluated. The experimental design used for this research is a factorial experiment with a Randomized Complete Block Design (RCBD), where the treatments include the use of vermicompost at four different levels (0, 100, 200, 300 g/plant) along with Bacillus subtilis suspension at two different concentrations (0, 10 ml. plant⁻¹). The growth parameters were shoot length, leaf number, leaf area, branch number, stem diameter, and shoot dry weight. The findings clearly show the effectiveness of the application of vermicompost in stimulating all vegetative growth parameters, particularly when applied at the highest concentration of 300 g. plant⁻¹. In the same way, the inoculation of Bacillus subtilis positively affected growth performance relative to those without inoculation. When combining 300 g. plant⁻¹ vermicompost and 10 mL/plant Bacillus subtilis, the maximum positive results were observed, including height of the main stem, leaf number, leaf area, branch number, stem diameter, and shoot dry weight being 63.0 cm, 20, 66.0 cm², 6, 9.2 mm, and 9.8 g, respectively. In comparison, the lowest results were found in the case of the untreated control.