The Role of Phosphate Solubilizing Bacteria and Free Living Nitrogen Fixing Bacteria on the Growth and Adaptation of Gmelina arborea Roxb. Grown on Degraded Land

The potential of phosphate solubilizing bacteria (Bacillus pantothenticus, B. megaterium, B. thuringiensis) and free living nitrogen fixing bacteria (Azospirillum lipoferum, Azotobacter chrococcum, and A. indicus) were used as biofertilizer to increase microbial population and stimulate the growth of Gmelina arborea Roxby. An experiment was conducted at DAS Citarum area, west Java. The aim of this experiment is to find out an effective and suitable inoculants used as biofertilizer in degraded soil. The treatments were arranged in Randomized Block Design (RBD) with 10 replications. The population of phosphate solubilizing bacteria and free living nitrogen fixing bacteria from degraded soil after 6 months were monitored. The result showed that after 6 months, bacterial inoculation increased the population of phosphate solubilizing bacteria and free living nitrogen fixing bacteria from 103 – 105 to 107 – 108, and stimulated Gmelina arborea Roxb.growth of about 46 – 48 persen. Microbial innoculant was clearly advantageous promoting plant growth at degraded soil. Gmelina arborea Roxb. Is one of good plants for rapid re-vegetation of degraded land. Jurnal Rekayasa Lingkungan (Journal of Environmental engeeniring) Vol.7 No.1. Maret 2011. Hlm: 89-95