Comparing weed composition in natural and planted hedgerows and in herbaceous field margins adjacent to crop fields

Abstract

Choinière, L. 2001. Comparing weed composition in natural and planted hedgerows and in herbaceous field margins adjacent to crop fields. Can. J. Plant Sci. 81: 313-324. Hedgerows and field margins are common features of the agricultural landscape in southern Québec. In the last decade, hedgerow establishment has been encouraged primarily for the prevention of soil erosion, though many farmers view them as reservoirs of invasive weeds and pests. In this study, we compared weed assemblages of several hedgerow types and herbaceous field margins. Ranking that takes into consideration weed abundance was clearly demonstrated: planted hedgerows > herbaceous field margins > natural woody hedgerows. The latter harboured many perennial plant species of less weedy propensity than planted hedgerows, which accommodated a larger number of weedy species. In planted hedgerows close to 50% of plants were weeds, even in their central position, although planted and natural hedgerows sheltered similar weed composition in their central parts. Likewise, most species inventoried in adjacent fields were weeds. Weeds characterising the central position of hedgerows/field margins were often species of wet habitats (Lythrum salicaria L., Equisetum arvense L., Cicuta maculata L.). Management practices of hedgerows and perhaps of crop fields adjacent to hedgerows may be mostly responsible for the abundance of weeds in hedgerows and field margins. Les haies brise-vent et les bordures herbacées font partie intégrante du paysage agricole du Québec méridional. L'implantation de haies a récemment été encouragée pour réduire les problèmes liés à l'érosion éolienne mais plusieurs producteurs agricoles voient toujours les haies comme des réservoirs d'espèces nuisibles. Nous avons étudié la composition et la distribution des espèces végétales nuisibles aux cultures dans différents types de haies et un patron clair de l'abondance de ces espèces a été trouvé: haies plantées > bordures herbacées > haies naturelles boisées. Ce dernier type de haie abritait plus d'espèces vivaces non nuisibles aux cultures que les haies plantées lesquelles abritaient surtout des espèces nuisibles. Ainsi, plus de 50% des espèces retrouvées dans les haies plantées étaient des espèces nuisibles, même celles présentes au centre des haies, malgré le fait que la composition spécifique des espèces nuisibles retrouvées au centre des haies naturelles et plantées était similaire. La plupart des espèces inventoriées dans les champs adjacents étaient aussi des espèces nuisibles. Plusieurs des espèces nuisibles retrouvées au centre des haies et des bordures herbacées sont typiques des milieux humides (Lythrum salicaria L., Equisetum arvense L., Cicuta maculata L.). La présence d'espèces nuisibles dans les haies brise-vent et dans les bordures herbacées semble être une conséquence de l'aménagement des haies en soi et possiblement des pratiques agricoles ayant cours dans les champs cultivés adjacents.

Weed cover, frequency and diversity in field plots and edges in the soybean central region of Argentina

“…The higher richness and diversity in spring-summer observed for edges relative to field plots concurs with other studies [8,19,20,29,30] which may be due to the absence of chemical control in edges as ocurred in another study [11]. Crop fields are characterised by considerable herbicide applications which may partially explain why their weedy vegetation is different from edges not subjected to these inputs [31].…”

Peer Review #2 of "Multiple ecosystem services from field margin vegetation for ecological sustainability in agriculture: scientific evidence and knowledge gaps (v0.1)"

“…De Cauwer et al 2008reported on the importance of sown field margin, which are managed through removal of the cuttings in suppression of weed spreading into the field. Similar findings on the importance of sown field margins with proper management for weed control are reported (West, Marshall & Arnold, 1997;Bokenstrand, Lagerlo & Torstensson, 2004, Boutin et al, 2001. This being the case, it can be concluded that field margin plants are not necessarily the source of weed infestation into the field, and that for…”

Influence of field margin type on weed species richness and abundance in conventional crop fields

“…Some empirical studies have shown that weeds occur at highest densities in the crop edge, and it was assumed that this high abundance was due to field margin weeds invading adjacent crop land 10,11 . In Canada, Boutin et al 14 reported that management practices of hedgerows and adjacent crop fields were mostly responsible for the abundance of weeds in hedgerows and field margins. In mid-western USA, Sosnoskie et al 13 found that elevation gradient and field shape were important factors not under the direct control of farmers that influence weed species diversity in field margins.…”

“…Investigations conducted to determine if and how weeds invade crop fields from the field margin 12 found a strong association between allele frequencies of Bromus sterilis species in field margins and in adjacent crop fields, indicating that the populations were genetically similar and suggesting that field margins contributed weeds to the crop field. Natural hedgerows contained many non-weedy, perennial plant species, while in planted hedgerows about 50% of the plant species were weeds 14 . In Canada, Boutin et al 14 reported that management practices of hedgerows and adjacent crop fields were mostly responsible for the abundance of weeds in hedgerows and field margins.…”