Arbuscular mycorrhizal and soil fertilization on post-transplant development of outplants of seven forest species

Seedling of seven forest species were raised in conventional nursery substr ate either infested or not with a mixture of arbuscular mycorrhizal fungi ( Glomus etunicatum, Gigaspora margarita and Acaulospora scrobiculata) and tr ansplanted into plastic pots with a low-fertility Oxisol amended with low o r high NPK-fertilization and with or without re-inoculation. It was found t hat either inoculation at nursery or at transplanting stage guaranteed high root colonization (>70%), growth response and favorable nutrition alter tr ansplant. Growth effects varied with treatments and with plant species. Ino culation benefits for shoot dry matter were as high as 800% for Colvillea r acemosa. Reduced growth was observed when seedling non-inoculated at nurser y stage were also not inoculated at transplanting, whereas nursery-inoculat ed ones grew well independently on soil fertility and re-inoculation. Enhan ced soil fertility did not increase shoot dry matter yield of Luehea grandi flora, Senna macranthera and Enterolobium contortisiliquum. It increased dr y matter of Cecropia pachystachya in the absence of mycorrhiza; of mycorrhi zal Senna multijuga and C. racemosa and of Sesbania virgata caused an incre ase in all treatments. Only C. racemosa did not respond to inoculation at t ransplanting.