Fitossociologia e banco de sementes de plantas infestantes em plantio de guaranazeiro

Abstract

Guarana is a plant that needs cultural treatment, as the presence of weeds will compete with the culture and interfere with its development, harming its production. An alternative means to control the infestation of invasive plants, as long as they are properly managed and the species chosen. For this, the knowledge of the seed bank in the soil and the survey of weeds in the field, the infestation in the cultures and define the management measures. The objective of this work was to quantify and identify weed species before and after the use of cover crops to control weeds. The experimental design adopted was completely randomized with four replications and five treatments, being four species of cover crops (Brachiariaruziziensis, Pennisetumglaucum, Canavaliaensiformis and Mucunadeeringiana) and a control treatment (without cover plant). A phytosociological survey was carried out before the implantation of cover crops and the other at the end of the cover crop cycle. For emergence flow, counting and identification of seedlings emerged from the seed bank, soil samples were collected at depths 0-10cm and 10-20cm. The first phytosociological analysis had Axonopus Fissifolius and Spermacoce latifolia as the species that had the highest number of individuals (1,102 and 778 respectively). For the second phytosociological survey, the weed species that obtained the highest IVI was Digataria horizontales, found several times in the seed bank, in most treatments. Brachiaria ruziziensis was the cover crop that was most effective in suppressing weeds. Seedling emergence peaked after 30 days, with a depth of 0 - 10 cm being the soil layer where the seed bank was more active.