Invertebrados edáficos e decomposição de resíduos vegetais em sistemas de uso do solo no semiárido da Paraíba.

Abstract

This work had as objective to characterize and to evaluate the occurrence of the soil fauna (meso and macrofauna) in soil use systems, as well as to study the leaves decomposition of native plants of the semiarid region of the Paraiba. The experiment was carried out in the NUPEÁRIDO (Núcleo de Pesquisa para o Semiárido), an experimental farm of the Universidade Federal de Campina Grande (UFCG), Patos, Paraiba, Brazil (07º04’85” S e 37º16’49” O) and 270m of altitude. The studied areas (treatments) were: AForest – area with specimens cultivated in the Caatinga, ACactus – area with cactus pear (Opuntia ficus – indica), AGoat + sheep – area that have goats and sheeps’ production, and APanasco – area with predominance of panasco grass (Aristida setifolia), from March to September 2008. The statistical design was split plot (plants leaves) and completely randomized (meso and macrofauna). It was used nylon bags with 20 cm x 20 cm and mesh of 1 mm2, containing panasco (Aristida setifolia), jurema preta (Mimosa tenuiflora) and malva branca leaves (Sida cordifolia) to the residues decomposition. The extraction of the mesofauna’s constituent population had made by a modified extractor Berlese-Tullgren and the collection of organisms was made according to the methodology modified of Trampa de Tretzel. To evaluate the ecological behavior of organisms it was measured the number of individuals comparing the communities using the index of diversity of Shannon and the index of equitability of Pielou. The results have showed that the dominant group of meso and macrofauna were respectively Protura > Collembola ≥ Acarina and Hymenoptera. The cactus pear area had the biggest density of soil fauna. The malva-branca leaves have showed better rates decomposition and, the area cultivated with Caatinga forest specimens was the management in which leaves presented higher rate decomposition.