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Phytosociology of weeds in sorghum-brachiaria integration systems under different forms of pasture deployment

The objective of this study was to evaluate the effect of the sowing modality of Brachiaria brizantha cv. Xaraés on the weed community and productivity of Sorghum bicolor cv. BRS 160 under the agricultural cattle-raising integration system. The treatments were constituted by sorghum forage intercropped with B. brizantha throwing-sown with light incorporation and without incorporation; sorghum forage intercropped with B. brizantha sown in a single row and in two rows in the leading row of the annual culture; and witnesses represented by the sorghum monocultures, with and without atrazine application, and of brachiaria. Major production of weed dry mass was observed in the monoculture treatments, with the species Digitaria horizontalis presenting the highest importance value and widest ground cover. For the intercropping cultivations, D. horizontalis presented lower importance and coverage values when forage sowing was performed by throwing with and without incorporation. Weed dry mass was similar between the intercropping treatments and the monoculture sorghum treatment with herbicide application. The monoculture sorghum plots that did not receive herbicide application showed higher weed infestation. No differences in the brachiaria dry mass values were found between the intercropping treatments; however, the sow throwing modality with and without incorporation showed larger stands, proving a better efficiency of this modality for pasture formation. However, this sowing modality leads to the development of forage plants near the sorghum cultivation lines, which may compromise the production of that culture by increasing competition. The type of B. brizantha sowing interferes in sorghum productivity and weed infestation.

intercropping; forage; herbicide; Brachiaria brizantha; Sorghum bicolor


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