SURVIVAL AND GROWTH OF PINUS-HALEPENSIS MILLER SEEDLINGS IN A SEMIARID ENVIRONMENT AFTER FOREST SOIL TRANSFER, TERRACING AND ORGANIC AMENDMENTS

A field assay was carried out to evaluate the effectiveness of several methods for the afforestation of a semi-arid area of southeast Spain with Pinus halepensis. The trial was designed as a two factor factoria l with four soil preparation treatments as the first factor (mechanica l terracing, manual terracing, manual terracing with the addition of u rban solid refuse [USR] and mechanical terracing with USR) and the add ition of fresh forest soil to the planting hole as the second factor. Twenty-one months after planting, the methods involving the addition o f USR significantly enhanced P halepensis performance, mechanical terr acing with USR being the most effective treatment in improving the sur vival and growth of the pines. The addition of forest soil significant ly enhanced P halepensis growth in all the soil preparation treatments except in the manual terracing with USR. P halepensis growth was stro ngly correlated with soil moisture content (r = 0.83; P < 0.01) which was greatest in the mechanical terracing with USR treatment. Soil fert ility levels, which were improved by organic amendment, were significa ntly correlated with seedling growth, particularly the phosphorus rate s (r = 0.75; P < 0.05). The positive effect of added forest soil appea rs to be of a microbiological nature.