title: Fertilization of Pinus pinea L. seedlings with a sewage sludge-based compost.
abstract: Two experiments were conducted to evaluate the effect of a sewage sludge-based compost (SSC) on the growth and mineral composition of containerized Pinus pinea L. seedlings. In the first experiment, five different substrates were tested: four binary mixtures of SSC and peat (100% SSC, 75% SSC, 50% SSC and 25% SSC, by volume) without fertilization, and a control substrate (peat-based substrate + fertilizer). Seedlings growing in the 100% SSC substrate showed the lowest growth, a consequence of both the low water availability and the high electrical conductivity that made SSC unsuitable to be the only component of a growing-media for pine ;seedlings'. The 50% SSC substrate presented physical and chemical properties similar to the control substrate and near the acceptable range for a growing-media. Moreover, no significant differences were found between growth of seedlings from treatment 50% SSC (without mineral fertilization) and seedlings from control treatment (with mineral fertilization). In the second experiment, a fertilization assay was performed with two substrates selected from the first experiment (50% SSC and control). The two substrates were fertilized with three levels of a macronutrient fertilizer (0.5, 1.0 and 2.0 g L( -1)) and two levels of a micronutrient fertilizer (0 and 0.4 g L(-1) of fertilizer containing only micronutrients). Results obtained suggest that replacing 50% (by volume) of peat-based substrate by the sewage sludge-based compost allowed: maintenance of the commercial value of seedlings; reduction of the amount of peat used in the substrate; a need for only half the amount of macronutrient fertilizer applied in the basal fertilization; and omission of micronutrient fertilization.
authors.affiliation: Departamento de Química Agrícola e Ambiental, Instituto Superior de Agronomia, TULisbon, Tapada da Ajuda, Lisboa, Portugal. henriqueribe@isa.utl.pt
authors.forename: Henrique M
authors.initials: HM
authors.lastname: Ribeiro
authors.forename: Ernesto
authors.initials: E
authors.lastname: Vasconcelos
authors.forename: Fernanda
authors.initials: F
authors.lastname: Cabral
authors.forename: Dina
authors.initials: D
authors.lastname: Ribeiro
mesh_terms: D005308:Fertilizers; D028223:Pinus / Q000737:chemistry / Q000254:growth & development*; D018517:Plant Roots / Q000737:chemistry / Q000254:growth & development; D018520:Plant Shoots / Q000737:chemistry / Q000254:growth & development; D036226:Seedlings / Q000737:chemistry / Q000254:growth & development*; D012722:Sewage; D012987:Soil; D044003:Sphagnopsida
chemical_list: D005308:Fertilizers; D012722:Sewage; D012987:Soil