Beneficial microbes are very essential for establishing tree plantations, particularly in wastelands or abandoned lands that make them suitable for cultivation. To establish a plantation in uncultivated farmland Gmelina arborea Roxb. tree seedlings were previously inoculated with the beneficial microbes (Arbuscular mycorrhizal (AM) fungi - Gigaspora albida, Glomus aggregatum), plant growth promoting rhizo bacteria (PGPRs) - Azospirllum brasilense, Bacillus megaterium) in single and combinations. The effect of these beneficial microbes were analysed and it was found that the seedlings inoculated with AM fungi + PGPRs1+ PGPRs2 have improved in growth and biomass (shoot length: 85.3 cm plant-1; root length: 40.2 cm plant-1; number of leaves: 42.3 plant-1; stem girth: 9.5 mm plant-1; shoot dry weight: 8.89 g plant-1; root dry weight: 1.81 g plant-1) than the control and individual microbe inocuations. The tissue nutrients (N: 9.1 mg g-1; P: 9.5 mg g-1; K: 6.1 mg g-1) found higher particularly in AM fungi + PGPRs inoculated seedlings. Thus, improved seedlings were transplanted in an uncultivated farmland and monitored for growth and survival. The seedlings planted in the uncultivated farmland showed significant growth improvement. The single (AM fungi, PGPRs1, PGPRs2) and dual (AM fungi + PGPRs1/PGPRs2) inoculated seedlings of G. arborea showed 75 to 87% survival whereas the combined treatment (AM fungi + PGPRs1 + PGPRs2) showed 96% survival in farmland. These results confirmed that these beneficial microbes significantly contributed to the establishment of G. arborea seedlings in the uncultivated farmland through the transfer of nutrients.

Barren laterite lands are available plenty in Kasargode District of Kerala, India and being used mainly for extracting laterite bricks for building construction. These lands are found barren due to lack of vegetation and rocky nature. Afforestation in these lands is very essential to avoid extraction of laterite bricks so as to prevent degradation of lands.  To develop vegetation in these laterite lands the soil properties of laterite was examined as a first step of afforestation process.  It was found that the soils have lack of plant growth promoting microbes (PGPM) and poor in major nutrients (N, P, K). Therefore, the PGPM specifically arbuscular mycorrhizal fungi (Glomus fasciculatum and Glomus geosporum) and bacteria (Azospirillum brasilense and Bacillus megaterium) were used for afforestation in laterite lands along with Swietenia macrophylla G. King a commercially important tree of Kerala, India.  The laterite soils were collected and used as potting media for growing seedlings of S. macrophylla in nursery and the cultured PGPM were inoculated in to the seedlings of S. macrophylla and maintained for 3 months. The PGPM inoculated seedlings showed improved growth, biomass and nutrient uptake. Thereafter the seedlings were transplanted at laterite lands at Karmanthodi, Bovikanam, Kasargode, Kerala, India and monitored their growth for 12 months. The seedlings inoculated with PGPM showed up to 98% survival rate with improved growth. From this study it was understood that PGPM have the potential to increase the efficiency of plant growth system in S. macrophylla seedlings through supply of essential levels of N, P and K that helped for successful afforestation in hardy laterite lands.