Weed seedbank size and composition in a long‐term tillage and crop sequence experiment

Abstract

Knowledge of the effects of agricultural practices on weed seedbank dynamics is essential for predicting future problems in weed management. This article reports data relative to weed seedbank structure after 18 years of continuous application of conventional tillage (CT, based on mouldboard ploughing) or no tillage (NT) within three crop sequences (continuous wheat, WW; wheat-faba bean, WF; and wheat-berseem clover, WB). Tillage system did not affect the size of the total weed seedbank, but altered both its composition and the distribution of seeds within the soil profile. In particular, the adoption of CT favoured some species (mainly Polygonum aviculare), whereas the continuous use of NT favoured other species (Papaver rhoeas, Phalaris spp. and Lactuca serriola). The effects of tillage system on weed seedbank size and composition were less pronounced in the WB cropping system than in either the WW or WF. Compared with WF and WB, WW resulted in an increase in total weed seedbank density (about 16 000 seedlings m-2 in WW, compared with 10 000 and 6000 seedlings m-2 in WF and WB, respectively) and a reduction in weed diversity, with a strong increase in some species (e.g. Polygonum aviculare). Our results for the effect of NT application on weed seedbank size and composition suggest that farmers should only apply such a conservative technique within an appropriate crop sequence

Weed seedling emergence in contrasting fodder crop systems following 30 years of cultivation in the lowlands of Northern Italy

“…The study indicates that the cropping systems had a significant impact on the abundance of the major weed species and the composition of the weed assembly, confirming the results of prior studies on a range of cropping and management systems (Menalled et al , 2001; Moonen and Bàrberi, 2004; Barroso et al , 2015; Ruisi et al , 2015; Rotchés‐Ribalta et al , 2017). The total number of emerged seedlings (which was a likely index of the total seedbank) was influenced by the presence of relatively few, very abundant species, while seemingly being not affected by the number of recorded species.…”

“…growing season or plant vigour) and management may affect the establishment, growth and reproduction of the occurring weed flora through resource competition and niche disruption (Liebman and Davis, 2000). Crop rotations compared to cereal monocultures allow a greater diversity in weed management techniques, which in return may allow improved weed control (Ruisi et al , 2015). Competitive cropping systems might potentially result in a reduction of both herbicide doses and applications (Blackshaw et al , 2006).…”

“…Competitive cropping systems might potentially result in a reduction of both herbicide doses and applications (Blackshaw et al , 2006). Crop rotations usually have cumulative effects on soil properties and biotic communities co‐existing with crops, and their effects are best evaluated by long‐term trials (Ruisi et al , 2015). Data based on the weed seedbank are a powerful resource to assess positive or negative effects of alternative cropping systems on weeds in the long run, in that the weed seedbank represents at the same time the track of the past soil and crop management and an indicator of possible future weed problems (Bàrberi et al , 1998; Rotchés‐Ribalta et al , 2017).…”

A functional diversity approach of crop sequences reveals that weed diversity and abundance show different responses to environmental variability

“…Compared to monocultures, crop sequences optimize soil health and nutrient use and prevent the development of pests and disease specialists of a crop species (Curl, 1963;Dias, Dukes, & Antunes, 2015). More particularly, crop sequences provide a better control of weed abundance than monocultures (Koocheki, Nassiri, Alimoradi, & Ghorbani, 2009;Liebman & Dyck, 1993;Ruisi et al, 2015) and can promote weed diversity in arable fields (Murphy, Clements, Belaoussof, Kevan, & Swanton, 2006;Ruisi et al, 2015;Ulber, Steinmann, Klimek, & Isselstein, 2009; but see Smith & Gross, 2007).…”

“…Indeed, most studies have investigated crop sequence effects on weed diversity and abundance by opposing monocultures with diversified crop sequences (e.g. Andrade, Satorre, Ermácora, & Poggio, 2017;Doucet, Weaver, Hamill, & Zhang, 1999;Koocheki et al, 2009;Murphy et al, 2006;Ruisi et al, 2015;Smith & Gross, 2007;Teasdale, Mirsky, & Cavigelli, 2018;Ulber et al, 2009).…”