YUSRAN YUSRAN1, RUKMI RUKMI2
1University of Hohenheim, Institute of Plant Nutrition, Germany
2Tadulako University, Forestry Departement, Agriculture Faculty, Indonesia
Paraserianthes falcataria (L.) Nielsen, in Indonesia called ``Sengon`` is a leguminous tree species widely grown for timber and used in reboisation programme in Indonesia. It is a valuable multipurpose tree for the humid tropics. One of the fastest growing of all tree species, it is used for pulp and other wood products, fuelwood, ornamental plantings and shade for coffee, tea, cacao and cattle and has good effect in the protection of soil by erosion. However, the quality of seedlings that produced by the farmers is still low. The application of beneficial microorganism is an interesting alternative to improve the seedling growth and might be an alternative or supplement to chemical fertilisers and fungicides. In this study, the synergistic effect of indigenous Rhizobium sp., Thelephora sp. and arbuscular mycorrhiza (AM) inoculation on improving seedling growth of P. falcataria plants was investigated in a greenhouse experiment.
Single Paraserianthes seeds were cultivated in pots each of which containing 2kg sterile soils/sand mixture (3:1) with and without Rhizobium sp. (1 g nodule per 10 ml with concentration of application 20ml per pot), Thelephora sp. (1 g fruit body per 10 ml with concentration of application 20ml per pot), Glomus sp. (250 g infected soil per pot) or none of both as control. 50 N, 50 P, 100 K, 50 Mg kg-1 soils were fertilised.
Soil inoculation with the selected Rhizobium sp., Thelephora sp. and Glomus sp. strain significantly improved the seedling growth of Paraserianthes. Seedling height and diameter stem of Paraserianthes was positively affected by both microorganism. The seedling biomass production of Paraserianthes was positively affected by both inoculums and was even higher in the combination of both inoculations compare to single application and untreated control. Moreover, roots of Paraserianthes were not only healthier but also showed a significantly higher percentage of AM infection in combination treatment of both inoculums, indicating the sinergism between both microorganisms. The level of AM-propagules in the soils were not generally low but rather indirectly as consequence of poor root development. The results suggest that both microorganisms are suitable as bioeffector agents that may ameliorate plant growth and health
Keywords: Glomus sp., leguminous tree, Paraserianthes falcataria, Rhizobium sp., Thelephora sp., arbuscular mycorrhiza