Phytosociology of spontaneous plants in organic cultivation of Amazonian spinach

The objective of this work was to carry out a phytosociological study on the community of spontaneous plants in organic spinach cultivation in the Amazon. The study was carried out at the Federal University of Acre, from May to July 2023. The cultivation of Amazon spinach was installed in a randomized block design, with five treatments and four replications. The treatments were alternative soil coverings, including: chestnut husk, rice husk, jambeiro foliage, grass straw and bare soil. The evaluation of weeds was carried out during the Amazon spinach harvest, after 45 days of cultivation. To sample weeds, the square method was used, with a sample measuring 0.5 m x 0.5 m (0.25 m2), launched twenty times (5 m2). Weed species were quantified and identified, followed by the calculations: density, relative density, frequency, relative frequency, abundance, relative abundance, relative dry mass, importance value index and relative importance. 18 weed species were identified in the weed community, belonging to 13 botanical families, with greater species diversity in the Malvaceae family. The most important species in cultivation were Digitaria horizontalis, Phyllanthus amarus, Amaranthus blitum and Acalypha alopecuroidea.