Crop type and management are key filtering factors of functional traits in the weed communities of regions with contrasting soils and climates

RAUBER, R.B; DEMARÍA, M; ARROYO, D; POGGIO, S.

APPLIED VEGETATION SCIENCE

WILEY-BLACKWELL PUBLISHING, INC

Lugar: Londres; Año: 2021

1402-2001

Questions: Weed community composition responds to the interactions between environmentaland management factors at different scales. The aim of this study wasto disentangle the relative contributions of factors defining the composition of weedcommunities through crop type and agronomic management at the field scale, andclimate and soil factors at the regional scale.Location: The study was carried out in croplands in the phytogeographic provinces ofEspinal and Pampas in central Argentina.Methods: The floristic and functional compositions of weed communities in maizeand soybean crops were characterized and compared using permutational multivariateanalysis of variance and non-metricmultidimensional scaling in the two regions.The Espinal and the Pampas differ in soil and climatic characteristics, but crops aregrown with similar management strategies due to the widespread use of no-tillageandagrochemicals.Results: Years of continuous cropping, previous crop and sowing date were the mostimportant factors modulating the species composition of both crops at field scale.Perennials and exotics were more abundant in the Pampas, whereas natives weremore abundant in the Espinal. Moreover, mechanically dispersed species were moreabundant in maize crops in the Pampas. Annuals and barochoric species were closelyrelated to the years of continuous cropping in maize. In soybean, more monocotyledonousspecies were observed in fields previously cropped with maize, whereasmore dicotyledonous and C3 species were observed in fields previously cropped withsoybean.Conclusions: Differences in species composition depend mainly on climatic and biogeographicalfactors. In contrast, the functional composition of the weed communitiesin maize and soybean is mostly determined by local factors at field level, which aremostly related to crop identity and agronomic management. The effects of farmingpractices determine the functional composition of weed communities, which makescrop rotation and thorough cleaning of harvester machines key strategies in the developmentof weed management.