Growth and nutrient uptake by slash pine seedlings under phosphate fertilizer sources

Abstract

The effects of changes in substrate nutrient availability, as a function of doses and sources of phosphate and controlled release fertilizer were investigated in slash pine (Pinus elliottii Engel) seedlings. Pine seedlings were cultivated in substrate composed of 50% clay soil from the subsurface horizon of a Nitosol, and 50% pure sand, uniformly mixed. Fertilizer sources were: natural phosphate, soluble phosphate and a controlled release fertilizer, applied as half (0.18 kg P2O5 m-3), full (0.36 kg P2O5 m-3) and twice (0.72 kg P2O5 m-3) the recommended dose, in a completely randomized design, with four replications. Assessments were made during the early seedling growth stage by evaluating morphological parameters, dry mass and nutrient accumulation at 330 days after germination. Results showed that controlled release fertilizer gave the best seedling growth, the largest stem diameter and the highest values for dry mass accumulation at 330 days after germination. Natural and soluble phosphates were not as effective to promote pine seedlings development as controlled release fertilizer, but the soluble phosphate was much better than natural phosphate.