Along with sugarcane, which is the main crop used for ethanol production, the sweet sorghum is a promising agronomic and industrial alternative for cultivation in water-stress regions. This study aimed at assessing the row spacing (0.70 m, 0.80 m and 0.90 m) and plant density (80,000 plants ha-1; 100,000 plants ha-1; 120,000 plants ha-1; and 140,000 plants ha-1) for the BRS 511 sorghum cultivar, combined with sowing and harvest times. A split-plot experimental design, in complete randomized blocks, with four replications, was used. The analyzed variables were plant height, stem diameter, shoot fresh and dry matter, broth volume and total soluble solids (ºBrix). The results showed isolated effects of plant density on plant height and stem diameter, as well as effects of row spacing on total fresh mass and broth volume. The most efficient productive effect for the sweet sorghum was observed in populations lower than 120,000 plants ha-1 and row spacing inferior to 0.80 m, associated with harvest at 120 days after sowing.

The aim of this study was to study the phytosociology of weed species in areas of pasture cultivated with Brachiaria decumbens and Cynodon sp. (Tifton 85), in Ceará State, Brazil. The square inventory methodology was used in order to assess the weed community. Weed samples were quantified and classified by family, genus and species, using books and classification keys. The classification and quantification data of species allowed to calculate the following phytosociological variables: frequency (F), relative frequency (Fr), density (D), relative density (Dr), absolute dominance (DoA), relative dominance (DoR), importance value index (IVI), and similarity index (IS). The Amaranthaceae family was the one with the greatest intensity of species in both areas, represented mainly by Alternanthera tenera colla and Amaranthus viridis. In the area cultivated with B. decumbens, Cyperus rotundus presented higher results for frequency, density and abundance. In the Tifton 85 area, Nicandra physalodes presented higher values of density and abundance. The similarity of weed populations in pasture areas was 42.11%, with four species common to both areas.

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O presente trabalho tem por objetivo divulgar uma ação extensionista, criada a partir da necessidade dos estudantes de Agronomia da UFC Cariri de se integrarem a este ramo. O Café com a Extensão é uma iniciativa do Programa de Educação Tutorial do curso de Agronomia da UFC – Cariri (PET Agro). As atividades contaram com um público alvo com uma média de 60 discentes, com participações dos docentes da UFC e IFCE. Conclui-se que com o PET Agronomia, em parceria com o IFCE, é possível pensar na formação de profissionais mais bem preparados e que, em pouco tempo, teremos uma região mais desenvolvida.