Container volume and controlled-release fertilizer influence the seedling quality of agonandra brasiliensis

Abstract

Agonandra brasiliensis is a tree from tropical forests, with a wide occurrence in the Brazilian Savannah region. Despite its potential as wood and for reforestarion, efficient protocols for its seedling production are still lacking. This study aimed to assess morphological characteristics for the seedling quality of A. brasiliensis, under nursery conditions, as a function of container volume and controlled-release fertilizer dose. The experiment was carried out in a 2 x 5 factorial scheme, testing two container volumes (1.8 L and 2.2 L) and five doses (0 g L-1, 1 g L-1, 2 g L-1, 4 g L-1 and 8 g L-1) of the encapsulated fertilizer Forth Cote™ (formulation NPK 15-09-12). The plots consisted of five homogeneous seedlings transplanted in polyethylene bags (15 cm x 35 cm) with washed medium sand substrate. The following characteristics were measured: shoot length; stem diameter; increases in length and diameter; total dry matter; shoot and root dry matters and the ratio between them. The Dickson Quality Index was also obtained. The seedling quality for morphological traits, such as shoot length, stem diameter and total dry matter, was especially favoured by treatments combining the controlled-release fertilizer at a dose around 5.0 g L-1 and container volume of 2.2 L.