PRODUCTION OF Pinus montezumae Lamb. WITH DIFFERENT SUBSTRATES AND CONTROLLED RELEASE FERTILIZERS

Abstract

Controlled-release fertilizers are not frequently used in forest nurseries, mainly because their advantages are unknown. The objective of this study was to test the effectiveness of three controlled-release fertilizers combined with two substrates. Pinus montezumae Lamb. plants were grown in polystyrene trays with three dosages (4, 6 and 8 g L^-1) of fertilizers (Basacote^® Plus, Multicote^® and Osmocote^® Plus) and two substrates: S1 (composted pine sawdust, composted pine bark and vermiculite 70:15:15) and S2 (peat moss, perlite and vermiculite 60:20:20). The study was conducted with a 2x3x3 factorial array. Nine and a half months after sowing, the effect of substrate, fertilizer and dosage on stem diameter, shoot dry weight, root dry weight, total dry weight and shoot/root ratio was significant. In substrate S1, the highest values occurred with the dosage 8 g L^-1 and in substrate S2 with the dosages 6 and 8 g L^-1. The concentration of N, P and K in foliage increased with the level of fertilizers. In 16 of the 18 treatments, mean stem diameters above 6 mm were obtained. The fertilizers retained 15 to 45 % N, P, K; Basacote^® retained the highest quantities of these elements. In S2 with 8 g L^-1 Basacote^®, Multicote^®, Osmocote^®, the plants had morphological characteristics recommended for use in plantations and the highest concentrations of N, P and K in foliage. Production of high quality plants is possible using controlled-release fertilizers combined with peat moss or pine sawdust.