Effect of Arbuscular Mycorrhiza Fungal Inoculation on Growth of Tropical Tree Species under Nursery and Post-Opencast Bauxite Mining Field in Bintan Island, Indonesia

Abstract

The purpose of this investigation was to examine the effects of native AM fungal inoculation on the growth of Gmelina arborea, Samanea saman, Falcataria moluccana, and Enterolobium cyclocarpum under nursery and post-opencast bauxite mining field conditions. Two native AM fungi, Rhizophagus clarus and Gigaspora decipiens, were inoculated into seeds of G. arborea, S. saman, F. moluccana, and E. cyclocarpum. The seeds were sown in post-bauxite mining soil and grown in the nursery for three months. Seeds without AM inoculation were used as the control treatment. The seedlings were transplanted into a post-opencast bauxite mining field and grown for 12 months. Arbuscular mycorrhizal fungal colonization and shoot and root dry weights were measured. Under nursery conditions, G. arborea inoculated with G. decipiens increased shoot and root dry weights by 1,431 and 359 %, respectively, while shoot dry weight of E. cyclorapum inoculated with R. clarus and G. decipiens increased by 510 and 220%, respectively, in comparison with control seedlings. Root dry weight of E. cyclorapum inoculated with R. clarus increased by 224%, in comparison with control seedlings. Shoot dry weight of E. cyclorapum inoculated with R. clarus increased by 90%, in comparison with seedlings inoculated by G. decipiens. Twelve months after transplanting into post-opencast field conditions, the shoot dry weight of F. moluccana inoculated with G. decipiens was higher than that of the control seedlings by 188%. Shoot dry weight of E. cyclorapum inoculated with R. clarus and G. decipiens increased by 198% and 149%, respectively, in comparison with control seedlings. Shoot dry weight of E. cyclorapum seedlings inoculated with R. clarus was higher by 20% than that of seedlings inoculated with G. decipiens. These results show that AM fungal inoculation promotes the growth of tropical tree species on post-opencast bauxite mining land.