Influence of the fertilisation method in controlled ectomycorrhizal inoculation of two Mediterranean pines

The influence of the fertilisation method: soluble (SF) vs. slow-release fertiliser (SRF) and of inoculation with Laccaria laccata (Scop.) Fr., Pisolithus tinctorius (Pers.) Coker & Couch and Melanogaster ambiguus (Vittad.) Tul & C. Tul. on ectomycorrhizal colonization and growth of Pinus pinea L. and Pinus pinaster Ait. was evaluated. For both pines, mycorrhization with L. laccata was not affected by the fertilisation method. Percentages of ectomycorrhizas (ECM) formed by P. tinctorius were dependent on the fertilisation method, the inoculum type (vegetative or spores) and the pine species involved. ECM formed by M. ambiguus were increased with fertilisation in both pines. Inoculation significantly improved P. pinea biomass when seedlings were fertilised with SRF whereas no effect was found in non-fertilised ones. For non-fertilised P. pinaster, inoculation with L. laccata and both inocula of P. tinctorius increased seedling biomass whereas fertilisation neutralised the fungal effect. Fertilisation increased P. pinea and P. pinaster biomass, independently of the inoculation treatment.