An investigation to enhance understanding of the stimulation of weed seedling emergence by soil disturbance

Abstract

Enhanced understanding of soil disturbance effects on weed seedling recruitment will help guide improved management approaches. Field experiments were conducted at 16 site-years at 10 research farms across Europe and North America to (i) quantify superficial soil disturbance (SSD) effects on Chenopodium album emergence and (ii) clarify adaptive emergence behaviour in frequently disturbed environments. Each site-year contained factorial combinations of two seed populations (local and common, with the common population studied at all site-years) and six SSD timings [0, 50, 100, 150, 200 day-degrees (d°C, base temperature 3°C) after first emergence from undisturbed soil]. Analytical units in this study were emergence flushes. Flush magnitudes (maximum weekly emergence per count flush) and flush frequencies (flushes year −1 ) were compared between disturbed and undisturbed seedbanks. One year after burial, SSD promoted seedling emergence relative to undisturbed seedbanks by increasing flush magnitude rather than increasing flush frequency. Two years after burial, SSD promoted emergence through increased flush magnitude and flush frequency. The promotional effects of SSD on emergence were strongest within 500 d°C following SSD; however, low levels of SSD-induced emergence were detected as late as 3000 d°C following SSD. Accordingly, stale seedbed practices that eliminate weed seedlings should occur within 500 d°C of disturbance, because few seedlings emerge after this time. However, implementation of stale seedbed practices will probably cause slight increases in weed population densities throughout the year. Compared with the common population, local populations exhibited reduced variance in total emergence measured within sites and across SSD treatments, suggesting that C. album adaptation to local pedo-climatic conditions involves increased consistency in SSD-induced emergence. SummaryEnhanced understanding of soil disturbance effects on weed seedling recruitment will help guide improved management approaches. Field experiments were conducted at 16 site-years at 10 research farms across Europe and North America to (i) quantify superficial soil disturbance (SSD) effects on Chenopodium album emergence and (ii) clarify adaptive emergence behaviour in frequently disturbed environments. Each site-year contained factorial combinations of two seed populations (local and common, with the common population studied at all site-years) and six SSD timings [0, 50, 100, 150, 200 day-degrees (d°C, base temperature 3°C) after first emergence from undisturbed soil]. Analytical units in this study were emergence flushes. Flush magnitudes (maximum weekly emergence per count flush) and flush frequencies (flushes year À1 ) were compared between disturbed and undisturbed seedbanks. One year after burial, SSD promoted seedling emergence relative to undisturbed seedbanks by increasing flush magnitude rather than increasing flush frequency. Two years after burial, SSD promoted emergence through increased flush magnitude and flu...

Interspecific variation in persistence of buried weed seeds follows trade‐offs among physiological, chemical, and physical seed defenses

“…Quantifying genetic and epigenetic contributions to seed dormancy (Chao, Dogramaci, Anderson, Foley, & Horvath, ; Gu, Kianian, & Foley, ) remains an important knowledge gap to be addressed as a means of identifying particularly persistent populations and also to determine whether in‐field environments may be manipulated to reduce weed seed dormancy (Nurse & DiTommaso, ). The efficacy of existing strategies for depleting the soil seedbank through seedling emergence, such as superficial soil disturbance to stimulate seed germination (“stale seedbeds”), may be enhanced by fine‐tuning them to species‐specific dormancy‐breaking requirements through multigenotype, multi‐environment studies (Long et al., ; Schutte & Davis, ; Schutte et al., ).…”

Disentangling the Effects of Tillage Timing and Weather on Weed Community Assembly

“…However, Fried et al [2] also reported that, after partitioning out the effects of timing of crop sowing and associated tillage practices, and weather conditions, only 18% of the explained variance in weed composition was due to crop type. Tillage is one of the main drivers of weed community assembly because primary tillage concomitantly buries and stimulates the germination of weed seeds [15], and secondary tillage kills the resulting seedlings, thereby decreasing seed density in the soil [16,17].…”

Arable weed species associated with soil tillage systems under Mediterranean conditions

“…In addition, the presence of a Mediterranean climate, rising temperatures, and altered precipitation patterns also influence the high variability in the occurrence of weed species associated with tillage systems (Cantero‐Martínez et al, ). In this context, combining the farming technique–environment interaction and the subsequently emerged community during a single crop cycle may represent a useful framework for understanding the direct effects of soil tillage systems on the density and diversity of weed communities (Schutte et al, ). Quantitative and qualitative weed data can therefore be used as an indicator regarding the state of the biodiversity in an agro‐ecosystem, and this information can be employed (Albretch, ; Moonen & Bàrberi, ) when selecting management programs (Fried et al, ; Storkey, Moss, & Cussans, ).…”

“…Thus, the chosen tillage systems are focused on the depletion of weed seedbanks by the stimulation of weed germination (Riemens, Van der Weide, Bleeker, & Lotz, 2007). Schutte et al (2013) observed differences in seed dormancy loss and germination as a response to superficial soil disturbances. García-Fayos, Bochet, and Cerdá (2010) have described some seed characteristics affecting plant establishment.…”

“…In addition, the presence of a Mediterranean climate, rising temperatures, and altered precipitation patterns also influence the high variability in the occurrence of weed species associated with tillage systems (Cantero-Martínez et al, 2007). In this context, combining the farming technique-environment interaction and the subsequently emerged community during a single crop cycle may represent a useful framework for understanding the direct effects of soil tillage systems on the density and diversity of weed communities (Schutte et al, 2013).…”