ABSTRACT
Inga laurina is a tree species widespread in South America, useful for agroforestry, forest restoration and urban forestry. This study aimed to evaluate the effects of inoculation with nitrogen (N) fixing bacteria and N fertilization on growth and quality of I. laurina seedlings. The experiment lasted 170 days and the seedlings were grown in plastic tubes with 115 cm3 capacity, containing a mixture 9:1 by volume of HS Florestal® and coconut coir dust as substrate. Six treatments were tested, with four separate inoculations (Bradyrhizobium japonicum 1 - BJ1, Rhizobium miluonense - RM, Bradyrhizobium japonicum 2 - BJ2 and Burkholderia cepacia - BC), a positive control - C+ (without inoculation and with weekly N fertilization, 60 mg dm3 of N as urea) and a negative control - C- (without inoculation and N fertilization). The treatments with inoculation were ineffective in relation to the growth of seedlings, since the average values of growth variables, specific leaf mass (SLM) and Dixon quality index (DQI) were significantly higher in the C+ compared to the other treatments. Nevertheless, the isolates RM and BJ2 were effective in the production of nodules, since they showed the highest average values of the dry mass of nodules (DMN). Moreover, the average values of Falker chlorophyll index (FCI) were significantly higher in inoculated treatments with respect to C-. The best results among the inoculation treatments were obtained for RM, followed by BJ2.
Bradyrhizobium; Burkholderia; Rhizobium