Impact of Benzyl Adenine (BA) Spraying and Nitrogen Fertilizer Addition on the Growth and Active Substance Content of Avena sativa L.

The field experiment was conducted at the second agricultural research station, which is affiliated with the College of Agriculture at Al-Muthanna University. This study took place during the winter agricultural season of 2022–2023. The experiment involved investigating the impact of two variables. The first factor under consideration was nitrogen, which was applied at four different levels (0, 40, 80, and 120 kg N ha−1). The nitrogen was added in three separate application stages: after emergence, during the elongation stage, and at the booting stage. The second factor examined in this study was benzyl adenine, which was applied to the plant at four different concentrations (0, 100, 150, and 200 mg L−1). The application of benzyl adenine was carried out in two separate batches. The first batch was applied during the elongation stage, and the second batch was applied at the booting stage. The experiment was conducted using a split-plot design with three replications following an RCBD. The main plots were assigned to different nitrogen fertilization levels, while the subplots were assigned to various benzyl adenine spraying treatments. The findings showed notable disparities in the effects of nitrogen addition, particularly in the treatment with a nitrogen application rate of 120 kg N h−1, affecting plant height, leaf area, and flavonoid content. The study's findings also revealed significant variations in the effects of benzyl adenine spraying. The treatment of 200 mg L−1 demonstrated the highest mean values for plant height, leaf area, carbohydrate content, and nitrogen content.