The Effects of Rhizobial Inoculation and Nitrogen Application on Root Nodulation and Seedling Growth of Dalbergia odorifera

To investigate the effects of inoculating different rhizobium strains and nitrogen application on the nodulation and seedling growth of Dalbergia odorifera, a controlled pot experiment was conducted with ten treatments, including six individual rhizobium strains, mixed inoculation, nitrogen application(N), mixed inoculation with nitrogen application(HN), and a control with neither inoculation nor nitrogen application(CK). After 90 days of inoculation, parameters such as nodule metrics, root characteristics, seedling height, and biomass were measured. The results indicated that all rhizobium inoculation promoted nodulation and improved growth parameters such as seedling height and biomass, with the HN treatment being the most effective. Compared to CK, the HN treatment increased root surface area, root volume, seedling height, aboveground biomass, and belowground biomass by 56.75%, 64.62%, 43.62%, 200.00% and 100.00%, respectively. Rhizobium sp. strain AFS005221 had the most significant growth-promoting effects. In conclusion, inoculating with different rhizobium strains can significantly improve the nodulation and growth parameters of D. odorifera seedlings. This study provides a scientific basis for improving the quality and sustainable management of D. odorifera plantation seedlings through rhizobium inoculation and nitrogen application.