Occurrence of Weeds in Areas Submitted to Tillage Managements for Soybean Cultivation in the Cerrado of Roraima

Abstract

Weeds from soils submitted to different tillage managements were identified in two consecutive years of soybean cultivation in the Cerrado of Roraima. The study was carried out in three areas: native area (NA), mechanically mowed native area (MA), and limed area (LA). A descriptive analysis of the phytosociological parameters relative density (Drr), relative frequency (Frr), relative dominance (Dor), importance value index (IVI), and index of relative importance (IRI) was performed to interpret the results. The weed similarity index (SI) was also calculated in the assessed areas. The highest relative frequencies were observed for Trachypogon plumosus (40.92%), Bulbostylis capillaris (18.52%), and Spermacoce capitata (18.33%) in the native area and T. plumosus (24.69%), Cyperus flavus (24.69%), and S. capitata (18.52%) in the mowed area. Among the species collected in the areas, the botanical families Poaceae, Cyperaceae, Fabaceae, and Rubiaceae are the most representative. The used managements contribute to the emergence of new species of spontaneous plants and weeds in the Cerrado of Roraima.

Plasticity on 'BRS 8381' Glycine max (L.) Merril Agronomic Attributes in Different Years of Cultivation in Roraima

“…This result may have been due to the higher rainfall ( Figure 1) during 2016. Knowing the height of the insertion of the first pod and the architecture of the soybean plants, these are genetically defined characteristics, which, however, can be influenced by several factors, such as sowing time, spacing, plant density, water supply, air temperature and soil fertility (Menezes et al, 2019). Thus, observing the values of temperature and rainfall that occurred in the two years of cultivation, it was found that the year 2015 had a higher average of high temperatures and less rainfall in relation to the year of cultivation 2016 (Figure 1).…”

Quantificação Do Banco De Semente De Plantas Daninhas Sob Diferentes Sistemas De Manejo Do Solo

“…Comumente o banco de sementes, em torno de 60% concentra-se nas camadas mais superficiais do solo (MENEZES et al, 2019), como observado neste trabalho.…”