Poda anual de Poincianella pyramidalis (Tul.) L. P. Queiroz e sua produção de lenha e forragem.

Abstract

Extensive farming is the predominant production system in the semi-arid region especially for agriculture and livestock. In this last one, animals live off the field by feeding on the biomass of the native species. Among the various Caatinga species with forage potential, we emphasize the Poincianella pyramidalis due to its production of firewood and the forage quality of its branches. This paper aimed at evaluating 1) the forage from the P. pyramidalis according to the intensity of the annual pruning of the outer branches in two consecutive years; 2) the effect of this pruning on the Diameter at Breast Hight (DBH) and; 3) the estimated accumulation of woody biomass, as well as the herbaceous forage produced underneath and outside the crown projection of the pruned trees. The study was conducted at the Lameirão Farm/UFCG, Santa Terezinha-PB. 20 adult P. pyramidalis trees were selected and each of them had their total height, crown height and crown circumference measured in April 2016 and April 2017. The pruning intensity obeyed the following treatments: T1 = no pruning of the branches; T2 = 25%, T3 = 50%, T4 = 75% and T5 = 100% pruning of the branches. The data from the herbaceous forage production from under and outside the trees’ crown projection were collected to estimate the production. In order to analyze the chemical composition of the forage of the P. pyramidalis branches and the herbaceous stratum was sent to the Laboratory of Animal Nutrition of the (UFCG – Brazilian acronym from Federal University of Campina Grande), in Patos-PB. The forage production of the branches varied from one year to another - from 2.16 to 1.33 kg.tree-1 in T2; 3.79 to 2.41 kg.tree-1 (T3); 7.07 to 1.48 kg.tree-1 (T4); and from 5.78 to 1.06 kg.tree-1 (T5), respectively. The shading from a P. pyramidalis canopy favored the production of herbaceous forage (1.60 t.ha-1 DM) when compared to the forage produced outside the canopy projection (1.07 t.ha-1 of DM) (P <5%). The pruning of the P. pyramidalis branches decreased between 30 and 80% in the second collection in the intensities of 75% and 100%. The pruning of up to 100% of the branches did not affect the increase of the DBH and the accumulation of woody biomass. The production of hebaceous forage is higher under than outside the crown projection of the P. pyramidalis. The pruning of the tree branches of P. pyramidalis does not affect the production of herbaceous forage under the crown. The chemical composition of the forage of P. pyramidalis branches is suitable for animal feeding.