Residues of Invasive Forage Species Inhibits the Growth of Caryocar brasiliense

ABSTRACT: Native species seedling growth may be affected by allelopathic substances released by invasive forage species, mainly in natural regrowth areas. Thus, this research aimed to evaluate the growth characteristics of pequi trees influenced by concentrations of plant residues of different forage species (Urochloa decumbens, Melinis minutiflora and Paspalum notatum). A randomized block experimental design was arranged in a factorial 3 x 4 + 1, with four replications. Treatments consisted of incorporating plant shoot residues of three forage species to pequi seedling substrate (soil + fertilizer) at four concentrations (1%, 2%, 3%, and 4% mass/mass), plus pequi seedlings grown in a residue-free substrate (control). Pequi plant height, stem diameter, and leaf number were evaluated at fortnightly intervals. Leaf area, root/shoot ratio, leaf area ratio, specific leaf area, and leaf mass ratio were determined 100 days after transplanting. Forage residues added to substrate inhibited pequi growth, and with increasing residue concentration, this inhibition was intensified. Pequi leaf characteristics proved to be more sensitive to allelopathic effect, especially from U. decumbens residues.