Influência de densidades de adubos verdes na comunidade de plantas espontâneas em um sistema de plantio direto orgânico em transição

Abstract

Weed management is a problem in production systems, especially in organic agriculture. Cover crops has been shown to be a promising alternative for the weed suppression in organic agriculture. Therefore, the present study aimed to evaluate the influence of the sowing density of a cover crops consortium of Avena strigosa, Vicia villosa and Raphanus sativus in a no-tillage system. The experiment was carried out in the Federal University of Fronteira Sul, in the 2019 and 2020 years, using a randomized block design with four replications and six treatments. The cover crops seeding densities used were 0%, 40%, 80%, 100%, 120% and 160% of the recommended dose. Weeds were identified and quantified by the frequency and dry matter production of shoots. The results demonstrate the effect of the density of cover crops sowing on the spatial and temporal suppression of weeds and on the community composition. In the first year, twelve different species were identified, especially palisade grass, cuban jute and wild radish. In the second year there was a 50% reduction in species, with emphasis on palisade grass and cuban jute. It was also possible to observe a significant reduction in the amount of readily germinating seeds in the soil seed bank. There was a predominance in the seed bank of palisade grass, cuban jute and wild radish in the first year, while in the second year the most relevant species were palisade grass and cuban jute. The use of cover crops is promising for the weed management in organic production systems, but it requires long-term studies to increase the reliability of the results necessary for the recommendation to farmers.