Levantamento florístico de plantas daninhas em pastagens no estado de Alagoas

Abstract

Knowledge of the biological and botanical information of weeds is essential for the adoption of management strategies, with the phytosociological survey being an important tool for generating knowledge about weed plants in different cultivation systems, since the indices obtained infer about the impacts that management systems and agricultural practices have on the dynamics of a weed community. In view of the above, the objective of the work was to carry out and analyze a phytosociological survey of weed species infesting pastures, aiming to obtain information about the families and species found. The study was carried out in the municipality of Roteiro, state of Alagoas, in a pasture area on the Agropecuária Santa Nazaré farm. To carry out the survey and phytosociological analysis, the isolated square method was used (Braun-Blanquet, 1950), where samples were taken from 10 random plots in an area of 500 meters, from a total area comprising 13 hectares. A 25 m2 square was used as a sampling unit, spaced 50m apart in each analysis, thrown at random 10 times. Within each sampled plot, plants were collected, followed by identification. A great diversity of weed plants was found, totaling 343 individuals collected, distributed in 9 botanical families and 13 species, with emphasis on 3 families, namely: Plantaginaceae with 142 species, Fabaceae with 69 species, and Turneraceae with 38 species. The species with the highest intensity present in the pasture area was Scoparia dulcis (Plantaginaceae), with VI equal to 86.20; IVI equal to 29.25; density of 56.80 plants m2 and frequency of 70.00%, which characterizes the concentrated occurrence of this weed in the collected points.