In a semiarid Mediterranean site in central Spain, field experiments were conducted on a Calcic Haploxeralf (noncalcic brown soil), which had been managed with three crop rotations and two tillage systems (no-tillage and conventional tillage) since 1987. The crop rotations consisted of barley→vetch, barley→sunflower, and a barley monoculture. The study took place in two growing seasons (1992–1994) to assess the effects of management practices on the weed seedbank. During this period, spring weed control was not carried out in winter crops. In the no-tillage system, there was a significant increase in the number of seeds of different weed species: anacyclus, common purslane, corn poppy, knotted hedge-parsley, mouse-ear cress, spring whitlowgrass, tumble pigweed, venus-comb, andVeronica triphyllos.Conversely, the presence of prostrate knotweed and wild radish was highest in plots under conventional tillage. These results suggest large differences in the weed seedbank as a consequence of different soil conditions among tillage systems, but also the necessity of spring weed control when a no-tillage system is used. With regard to crop rotations, the number of seeds of knotted hedge-parsley, mouse-ear cress, and spring whitlowgrass was greater in the plots under the barley→vetch rotation. Common lambsquarters dominated in the plots under the barley→sunflower rotation, whereas venus-comb was the most frequent weed in the barley monoculture. Larger and more diverse weed populations developed in the barley→vetch rotation rather than in the barley→sunflower rotation or the barley monoculture.

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Del Monte JP & Dorado J (2011). Effects of light conditions and after‐ripening time on seed dormancy loss of Bromus diandrus Roth. Weed Research51, 581–590. Summary Bromus diandrus is an emerging problem in barley crops in temperate climates, owing to its ability to adapt to certain farming techniques, as well as the absence of an efficient means of control. The aim of this study was to evaluate the germination of B. diandrus as a function of light conditions, time after ripening, temperature and water potential. Our results indicate that light conditions were the principal factor affecting germination and that seeds had negative photoblastism. Darkness modified the hydrotime parameters of the seeds somewhat, for example, by decreasing the values of Ψb and by favouring dormancy loss. The after‐ripening time significantly modified the hydrotime parameters of the seeds, causing Ψb to drift towards more negative values (greater dormancy loss) as the after‐ripening time increased. The combination of both variables explains the dormancy dynamics of this species in Mediterranean climates that are characterised by two distinct germination flushes, coinciding with two periods when soil humidity and temperature are not limiting. The first and main cohort of seedlings would emerge in autumn, originating from young buried seeds. A second cohort would emerge in the spring, from mature seeds on the surface of the soil.