Avena sterilis and Lolium rigidum infestations hamper the recovery of diverse arable weed communities

Abstract

Summary Intensification of agricultural practices has severely reduced weed diversity in arable fields, which affects the delivery of ecosystem services. However, in parallel, some species have benefited from intensive farming and have vastly increased their abundance, as is the case for Lolium rigidum and Avena sterilis in cereal fields. These highly competitive species severely reduce yields but can also compete with other weed species, and, when less intensive practices are applied, they might limit the recovery of weed diversity and the success of arable species reintroductions. A gradient of infestation was established in a winter wheat field in Catalonia (north‐eastern Spain) by sowing seeds of both species at three different densities to test their effects on the abundance, diversity and composition of the natural weed community. The emergence of seeds and the survival and biomass of transplanted seedlings of two rare species, Agrostemma githago and Vaccaria hispanica, were also evaluated. Avena sterilis and L. rigidum infestations reduced the diversity, abundance and biomass and changed the composition of the natural weed community, even at low infestation densities. Moreover, infestations of both species affected the overall performance of A. githago and V. hispanica. This study reveals that A. sterilis and L. rigidum are highly competitive and that their infestations might hamper the recovery of diverse weed communities. Their densities should be considered when selecting suitable sites for promoting diversity and reintroducing rare species.

Mitigating crop yield losses through weed diversity

“…De plus, même si de multiples espèces concurrentes sont présentes à cette échelle locale de la compétition, les traits des espèces interagissent avec l'environnement et une espèce peut être dominante une année et subordonnée l'année suivante (Mariotte, 2014 ;Funk et Wolf, 2016). Finalement, les espèces adventices concurrentes et dominantes peuvent réduire l'aptitude des espèces subordonnées à croitre, dont l'abondance peut diminuer au fil du temps (Poggio et Ghersa, 2011 ;Armengot et al, 2017 ;Gibson et al, 2017).…”

Burial depths favor Italian ryegrass persistence in the soil seed bank

“…In cropping systems, soil seed bank represents a potential target for management where temporary changes in environmental conditions and soil practices could affect weed population dynamic and exhausting the soil seed bank (Shaner and Beckie, 2014;Armengot et al, 2017). For example, mechanical control during the harvest of grain crops with the Harrington Seed Destructor Machine (HSD) could destroy more than 95 % of the annual ryegrass (Lolium rigidum Gaudin.)…”

Neutral weed communities: the intersection between crop productivity, biodiversity, and weed ecosystem services

“…Further research is needed to develop systems that promote diverse and neutral weed communities in each context. In addition, research is needed to develop strategies for managing aggressive weed species that impede efforts to increase weed community diversity (Armengot et al 2017). These species may require specific control measures, that is, the application of our second approach.…”