Contrasting weed species composition in perennial alfalfas and six annual crops: implications for integrated weed management

Abstract

-Weed communities are most strongly affected by the characteristics and management of the current crop. Crop rotation may thus be used to prevent the repeated selection of particular weed species. While weed communities are frequently compared among annual crops, little is known about the differences between annual and perennial crops that may be included in the rotations. Moreover, nearly all existing studies (17 articles reviewed) are based on local field experiments rather than commercial fields. We compared the weed composition in perennial alfalfas (Medicago sativa) and six annual crops: winter wheat (Triticum aestivum), oilseed rape (Brassica napus), pea (Pisum sativum), sunflower (Helianthus annuus), maize (Zea mays) and sorghum (Sorghum bicolor) using data from 632 commercial fields in western France. Weed species composition showed the strongest dissimilarities between perennial alfalfas and all annual crops, followed by the well-known differences between autumn-and spring/summer-sown annual crops. Indicator Species Analysis showed that most weed species either preferred perennial alfalfas (including Taraxacum officinale, Veronica persica, Crepis spp., Poa trivialis, Silene latifolia, Capsella bursa-pastoris and Picris spp.) or annual crops (including Mercurialis annua, Galium aparine, Fallopia convolvulus, Chenopodium album and Cirsium arvense). Perennial alfalfas thus suppressed many weeds that are widespread (and sometimes problematic) in annual crops while favouring other species. Shifted weed composition and reduced frequency of several noxious weeds suggest that perennial alfalfas may be used as a valuable part of integrated weed management, reducing the need for herbicides and sustaining plant and animal diversity in agricultural landscapes. crop diversification / temporary grassland / perennial forage crop / alfalfa / Medicago sativa / plant community composition

Which cropping systems to reconcile weed-related biodiversity and crop production in arable crops? An approach with simulation-based indicators

“…The strong influence of tillage on weed seed offer for birds and insects was not surprising as tillage influences the density of surface seeds by burying and excavating seeds and stimulating germination (Mohler, 1993). The better performance of low or no-till systems predicted here is consistent with studies on seed predation (Meiss et al, 2010;Westerman et al, 2011;Trichard et al, 2014). The same is true for the increase in bird food in case of rare or no mouldboard ploughing, leaving over-winter stubbles that favor seed-eating birds (Wilson et al, 1996;Robinson and Sutherland, 1999;Moorcroft et al, 2002;Cunningham et al, 2004).…”

Achievements and Challenges in Improving Temperate Perennial Forage Legumes

“…From the environmental standpoint, its relatively high energy cost (Gallego et al, 2011) can be compensated by various advantages associated with the introduction of a perennial legume in a cereal-based cropping system, such as increased soil structure and fertility, lower nitrogen leaching, and easier weed management (e.g., Meiss et al, 2010).…”

The influence of environment, management and site context on species composition of summer arable weed vegetation in Hungary

“…Differences in the timing of soil cultivation and sowing date, relative to crop species induces the development of different weed communities (Ujvárosi ; Meiss et al. ; Gunton et al. ).…”