Bank of Weed Seeds in Agrosystems in the Brazilian Cerrado

Abstract

-The seed bank is the reserve of viable seeds found in the soil and is related to diversity and abundance of species that make up the weed populations. This study aimed to determine the seed bank in four distinct environments (grazing area, area of vegetables, annual crop area and perennial crop area) in two seasons (rainy and dry season). To determine the seed bank, each environment was divided into four sub-areas of 0.2 hectares, considering that each area was a repetition, totaling 16 experimental units. Samples of 0.8 kg were taken from each area, and each sample was distributed on a plastic tray and allowed to germinate in a greenhouse. The density of the individuals was determined by observing the number of emerging seedlings in the trays, performing the counting at every 18 days. Evaluations were made for ninety days in each season. The germination curve was calculated, as well as the Shannon diversity index (H'), the Sorensen similarity index and the relative importance. The seven main species identified in the environments were Cyperus rotundus, Nicandra physaloides, Galinsoga parviflora, Alternanthera tenella, Panicum maximum, Portulaca oleracea and Eleusine indica. Among the studied environments, during the rainy season, the highest number of individuals was found in annual crop and the greatest diversity in the evergreen environment. During the dry season, the number and diversity of individuals were lower and similar in all environments.Keywords: rainy season, dry season, Shannon index, relative importance, diversity. Palavras-chave: estação das chuvas, estação da seca, índice de Shannon, importância relativa, diversidade. RESUMO -O banco de sementes é a reserva de sementes viáveis encontradas no solo e está relacionado à diversidade e abundância das espécies que compõem as populações de plantas daninhas. Com este estudo, objetivou-se determinar o banco de sementes em quatro ambientes distintos (área de pastagem, área de hortaliças, área de cultura anual e área de cultura perene), em duas épocas do ano (estação das chuvas e da seca

Bovine manure as a dispersing agent for weeds and invasive alien plants

“…The diversity and evenness of the seed bank was 1.485 and 0.42, respectively. These values were different from those obtained by Jakelaitis et al (2014), Mesquita et al (2016), Cardoso et al (2016) and Ferreira (2017), as well as the structural parameters also differed from those found in the consulted studies (Diniz et al, 2017;Ferreira, 2017;Corrêa et al, 2018;Carmona, 1995;Deiss et al, 2018;Mesquita et al, 2016).…”

Coberturas vegetais na entressafra de culturas afetando o banco de sementes de plantas daninhas

“…O conhecimento do banco de sementes de plantas daninhas da área cultivada apresenta grande importância por resultar em melhores decisões sobre manejo e medidas de controle, buscando a redução do desenvolvimento e produção dessas sementes e consequentemente, menor custo para seu manejo (Cardoso et al, 2016). O cultivo consorciado de grãos com forrageiras pode promover a supressão das plantas daninhas pela rapidez de produção de biomassa dessas culturas, antes da semeadura da cultura produtora de grãos (Castro et al, 2011).…”

“…Outra forma de entender a dinâmica das plantas daninhas nas áreas de cultivo é por meio do levantamento fitossociológico, que permite comparar as populações de plantas daninhas no tempo e espaço (Cardoso et al, 2016), proporcionando a interpretação quantitativa da estrutura da comunidade e suas relações ecológicas (Ferreira et al, 2014).…”

Weeds in Soybean Cultivation With Different Predecessor Cover Crops

“…One way to access weed plant communities' information is through phytosociological surveys, allowing us to study plant communities from a floristic and structural point of view, comparing weed populations over time and space (Pitelli, 2015;Cardoso et al, 2016). Phytosociological evaluation allows comparing weed populations through indexes such as density, relative density, frequency, relative frequency, abundance, relative abundance, and importance value index.…”

“…The seed bank is a seed reserve in the soil with dynamic behavior due to the entry and exit seed processes, which will provide new individuals' supply flow to the plant communities over time (Jakelaitis et al, 2014). The seed longevity in the soil depends on the species, the environmental conditions, and depth, with dormancy representing the primary means of seed preserving (Santos et al, 2015;Cardoso et al, 2016).…”