Phytosociological survey weed in Amazonia eastern black pepper crop.
The black pepper crop (Piper nigrum L.) in Brazil originated in the 1930s through Japanese immigration and has since continued as one of the main agricultural crops of economic interest in the Amazon. The objective of this work was to evaluate the weed community in the black pepper crop in the Eastern Amazon. Data were collected in five areas with pepper cultivation in Belos Prazeres, a rural area in Cametá municipality, in Pará. For weed community evaluation, four samples were taken in each cultivation area of 1.0 m2. Based on the data collected from invasive species, the phytosociological indexes were determined: density, relative density, frequency, relative frequency, abundance, relative abundance, relative fresh mass, importance value index and relative importance value index. Among the species that composed the weed community Spergula arvensis, as well as Galinsoga parviflora, Tarenaya spinosa and Cabomba furcata were the most significant, integrating most of the parameters analyzed. The specie S. arvensis was the only species to be represented in all evaluated phytosociological indexes.