Root growth potential in nursery Pinus halepensis Mill. seedlings. Fertilization effect

Abstract

In response to the importance of Root Growth Potential (RGP) attribute as a field performance potential predictor, this paper analyses the relationship between nursery fertilization and this attribute by mean of applying several mineral nutrition treatments (3, 5, 7 g/L Osmocote 9-13-18, Osmocote 17-10-10, 5 g/L Osmocote 15-8-11) in an experiment with Aleppo pine seedlings. Significative differences in the Root Growth Potential response between treatments were found; in particular, seedlings produced with 9-13-18 showed an increase in new roots produced (maximum value of 74 new roots > 1 cm corresponding to 7 g/L of this fertilizer) comparing with other compositions. After seeking univariable relationships between morphological or physiological attributes and RGP, no significative correspondence was found. In addition, seedlings survived over 70 per cent one year after planting in semiarid conditions, irrespective the mineral nutrition treatment considered; this indicates high vigor of the stock, even for the treatment showing a lower response in PCR (17 roots > 1 cm).