Manejo sustentável de Attalea maripa (Aubl.) Mart. (inajá) em sistema silvipastoril na Amazônia Oriental.

Abstract

In the Amazon region, at least 80 % of the deforested areas are currently occupied by pastures or soybean. As a result, large zones of pastures are degraded or being degraded from the agricultural point of view. Therefore, the purpose of this study was to evaluate the floristics and phytosociology of naturally regenerated vegetation and to sustainably manage the palm Attalea maripa (Aubl.) Mart. (maripa palm and inaji in Brazil), both in a silvopastoral system (SPS). The study was carried out in Bonito, Pari, in the eastern Amazon region, in a SPS of Brachiaria brizantha (Rendle) Schweickc (palisade grass and braquiarmo in Brazil) and cattle farming. Initially, structured interviews were carried out with the family farmers of the area. Then, eight sampling areas of 50 x 50 m, totaling two hectares, were installed. In the three following years, all plants with height 10 cm were counted and botanically identified. Thereafter, an experiment was installed on two hectares to evaluate the effect of palm pruning, hand mowing, removal of the vegetation around the trees and mineral fertilization on growth, flowering, fruiting, and trunk quality of adult maripa palms, in a completely randomized, split plot design with 10 treatments (2 management forms x 5 evaluation periods), with 4 replications, evaluating 8 adult palms per plot (50x50m). The first management form (T1) consisted of mowing the pasture by hand, semi-mechanized pruning of the fronds, sheaths, spathe and old maripa bunches, followed by manual removal of the vegetation around the palm trees and topdressing with 300g N-P-K fertilizer (10-28-20) per adult tree, every six months, for three years. In the second management (T2), the pasture was mowed by hand only. Structured interviews with the family farmers were carried out with questions related to the socioeconomic conditions and techniques of implementation and management of the SPS. The results showed a low species diversity in the case of natural regeneration, with predominance of late successional species, with tree growth habit and potential use for timber. The species Vismia guianensis, Attalea maripa and Eschweilera coriacea are ecologically the most important. The pruning, removal of vegetation around the palm trees and nitrogen fertilization favor stem diameter growth, increase flowering and fruiting, reduce insect attacks, and improve the quality of the palm trunks of Attalea maripa in the SPS investigated in this study.