Initial growing, phosphorus critical levels and phosphate fractions in forest species

An experiment under greenhouse conditions was carried out at Universidade F ederal de Lavras, Minas Gerais State, Brazil, to evaluate the growth of see dlings, phosphorus critical levels and phosphate fractions, in forest speci es growing under four phosphorus levels. Seedlings of Schinus terenbinthifo lius Raddi (aroeirinha), Chorisia speciosa St. Hill. (paineira) and Syzygiu m jambolanum Lam. (jambolao) were cultivated on an Oxisol fertilized with 0 , 150, 300 and 600 mg dm(-3) of P. The seedlings were harvested 180 days af ter germination and analysed for P forms. In all levels of phosphorus addit ion, the paineira produced higher aerial and root biomass than aroeirinha a nd jambolao, and presented higher contents of organic phosphorus and higher relative participation of organic phosphorus in the total acid soluble pho sphorus under all phosphorus levels. The improved growth rate of paineira w as attributed to a greater efficiency in the metabolic adjustments of this species in relation to phosphorus nutrition, indicating that this species c an grow in soils of variable P levels.