Impact of Gliricidia sepium mulch enriched with native Sri Lankan bacterial strains on cinnamon (Cinnamomum verum)

The integration of organic mulches with beneficial microorganisms offers a sustainable strategy for enhancing soil fertility and plant productivity. This study evaluated the effects of Gliricidia sepium mulch enriched with two native bacterial strains (I-I and I-II) from Sri Lanka on the vegetative growth, essential oil yield, and soil nutrient status of Cinnamomum verum variety Sri Gemunu under greenhouse conditions. A 12-month experiment was conducted in a completely randomized design with three treatments: control (mulch only), bacterial strain I-I enriched mulch (G I-I), and bacterial strain I-II enriched mulch (G I-II). Vegetative growth parameters, essential oil yield, and soil nutrient levels were assessed. Both bacterial treatments significantly improved plant height, stem circumference, leaf number, and root length compared to the control, with G I-II exhibiting significant performance in most growth metrics. Soil analysis indicated significantly elevated phosphorus levels in both inoculated treatments, while nitrogen levels increased only in the G I-I treatment. These findings highlight the potential of plant growth promoting bacteria-enriched Gliricidia sepium mulch to enhance vegetative growth and soil fertility in cinnamon cultivation, suggesting potential gains in overall oil productivity, supporting its relevance in sustainable cinnamon production systems.