Abstract

FONSECA, Wéverson L. et al. Influence of Sorghum bicolor on the emergence and development of Senna obtusifolia. Rev. de Ciências Agrárias [online]. 2020, vol.43, n.2, pp.67-85.  Epub Apr 14, 2020. ISSN 0871-018X.  https://doi.org/10.19084/rca.15266.

In the search for alternatives to weed control, the physical and allelopathic effect of cover crops has been studied. The objective of this work was to evaluate the allelopathic potential of Sorghum bicolor in the emergence and growth of the weed Senna obtusifolia. The experiment was conducted in a greenhouse using a completely randomized experimental design, with four replications, in a factorial scheme (2 x 4) + 1, consisting of two soil addition forms of S. bicolor dry biomass (built-in and surface) with four amounts of the cover crop straws (3, 6, 9 and 12 t ha-1), plus one treatment without the use of cover crop (control). The analyzed variables were total number of emerged plants, leaf area, shoot dry matter, root volume and root dry matter of S. obtusifolia. The different amounts of dry biomass addition of S. bicolor were efficient in the control of S. obtusifolia, with a significant reduction (more than 50%) in the emergency when it was used in quantities from 2.81 t ha-1. Regardless of the biomass amount of S. bicolor, its use on the soil surface provided a greater reduction in the number of emerged weed plants. While the use of biomass incorporated in the soil, provided greater reduction of the growth of S. obtusifolia.

Keywords : allelopathy; alternative control; cover crop; forage sorghum; weed.

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