The effect of organic material type and foliar application of plant extracts on the vegetative growth characteristics and volatile oil yield of rosemary plant

Abstract

A factorial field experiment was conducted during the 2024-2025 growing season at the research station of the College of Agriculture, University of Kufa, under green shade cloth (60% light transmission) to investigate the effects of organic materials and foliar plant extracts on vegetative growth and volatile oil yield of rosemary (Rosmarinus officinalis L.). The experiment followed a randomized complete block design with three replications. Two factors were examined: organic material type [wheat residues (O1), mushroom residues (O2), and control (O0)] applied at 5 tons ha⁻¹, and foliar plant extracts [moringa extract (E1), hibiscus extract (E2), and control (E0)] applied at 10 ml L⁻¹. Results demonstrated that wheat residues significantly increased leaf number (3,505 leaves plant⁻¹), shoot dry weight (40.54 g), and branch number (44.59 branches plant⁻¹) compared to other treatments. Hibiscus extract enhanced plant height (42.11 cm) and branch number (45.70 branches plant⁻¹), while moringa extract maximized leaf number (3,233.3 leaves plant⁻¹). For essential oil characteristics, mushroom residues produced superior oil yield (1.26%) and refractive index (1.746 nm). The interaction O2×E0 achieved the highest oil yield (1.41%), indicating significant synergistic effects. These findings suggest that strategic selection of organic materials combined with appropriate foliar extracts can substantially enhance rosemary production systems for commercial cultivation