Tree Biometrics and Rhizosphere Microbial Population on Different Gmelina arborea Provenances

A study was conducted at All India Co-ordinated Research Project on Agroforestry, Odisha University of Agriculture and Technology, Bhubaneswar, Odisha, India, from June 2021 to June 2023. It was laid out in Randomized Block Design with three replications and seven treatments of Gmelina arborea, viz., T1 (Chandaka), T2 (Nuapada), T3 (Nilgiri), T4 (Rayagada), T5 (Durgaprasad), T6 (Jhargram) and T7 (Kahikuchi). This study revealed notable variations in growth and other parameters across provenances (treatments). The tree growth indicators were statistically significant. T6=Jhargram provenance of Gmelina arborea consistently exhibited the highest performance, with biometrics such as tree height, DBH, crown spread, number of branches, and basal girth was 6.30 m, 10.24 cm, 1.98 m, 13 and 29.43 cm, respectively, however T3=Nilgiri provenance showed the lowest overall tree biometrics. The above ground biomass, below ground biomass, total biomass production, and carbon sequestration in the Gmelina arborea were maximum in T6=Jhargram provenance viz., 13.68 t/ha, 3.81 t/ha, 17.49 t/ha and 8.74 mg C/ha respectively. The available N was highest (173.49 kg/ha) in T6. The available P and K were highest in T7 viz. 49.66 kg/ha and 49.69 kg/ha respectively. The CFU (Colony Forming Units) in fungi and bacteria were maximum in T6 69.70 × 104/ml g and 389.17 × 106/ml g respectively. However in actinomycetes, the CFU was highest in T1 (337.49 × 106 /ml g). The highest litterfall occurred in February (58 g/m2). The treatment T6 as the most productive, with the highest overall yield (timber +fuel wood) of 332.05 t/ha. T6=Jhargram provenance also gave the highest net return (Rs13.03 lakhs) per hectare with a BCR (3.89).