FLORISTIC COMPOSITION AND PHYTOSOCYOLOGY OF SPONTANEOUS PLANTS IN PASTURES OF BRACHIARIA (Syn. Urochloa) IN THE NORTHESTE OF PARÁ STATE

Abstract

ABSTRACT: The success of programs of management of spontaneous plants depends on the knowledge of their biological and ecological characteristics. The objective of this research was to characterize the floristic composition and phytosociology in spontaneous plant populations in pasture ecosystems cultivated more than ten years, in the municipality of Ipixuna do Pará, Northeast of Paraense, considering three species of grasses (Brachiaria (Syn. Urochloa) humidicola, Brachiaria (Syn. Urochloa) brizantha cv. Marandu and Brachiaria (Syn. Urochloa) decumbens cv. Basilisk). The studies were conducted in the Municipality of Ipixuna do Pará, northeastern region of Para. For this study was applied the square inventory. Afterwards the identification and counting of the plants were carried, and later identification was made through specialized literature and comparisons with virtual herbaria. The Sörensen Similarity Index (ISS) was expressed in percentage, being maximum (100%) when all species are common to both areas and minimum (0%) when there are no common species. It was verified that the floristic composition in the pasture of B. (Syn. Urochloa) humidicola, were identified, 10 families, 12 genera and 12 species of spontaneous plants, in B. (Syn. Urochloa) brizantha cv. Marandu, 12 families, 15 genera and 16 species were idealized, while in the ecosystems with B. (Syn. Urochloa) decumbens cv. Basilisk, 13 families, 24 genera and 25 species were found. The highest index of similarity was between the ecosystems B. (Syn. Urochloa) humidicola and B. (Syn. Urochloa) brizantha, while the smaller one was between the ecosystems B. (Syn. Urochloa) decumbens and B. (Syn. Urochloa) humidicola.KEYWORDS: Ecosystems, Index of similarity, Weed community.