EFFECT OF MYCORRHIZAL INOCULATION AND SOIL RESTORATION ON THE GROWTH OF PINUS-HALEPENSIS SEEDLINGS IN A SEMIARID SOIL

An experiment was carried out to evaluate the growth of mycorrhizal Pi nus halepensis seedlings planted in a semiarid soil amended with urban refuse in southeast Spain. Three fungal species were used: Pisolithus tinctorius, Rhizopogon roseolus, and Suillus collinitus. After 8 mont hs, inoculated seedlings grown under controlled conditions did not dif fer significantly from controls with regard to plant height and nutrie nt assimilation. Other features such as root development and stem dry weight showed that the plants grew better in the absence of mycorrhiza l inoculation. The mycorrhizal seedlings and the controls were planted in three experimental plots treated with urban refuse (0, 6, and 12 K g m-2). After 1 year of growth under field conditions the results show ed that the type of fungus inoculated significantly influenced P. hale pensis development. This effect varied with the dose of urban refuse. Plant growth was encouraged by the application of refuse but only at t he lowest dose. Under these conditions P tinctorius was the most effec tive fungus and R. roseolus yielded poorer plant development. The high est application of urban refuse led to notably worse results and a sig nificant decrease in seedling growth compared to controls. In the cont rol plot (without refuse) S. collinitus was the most effective fungus in plant growth improvement. The smallest application of urban refuse had a positive effect on the assimilation of N, P, and K in seedlings inoculated with P tinctorius and S. collinitus.