Seed production by an arable weed community

After cultivation in early April of a sandy loam soil with 9500 apparently viable seeds/m² in 0–10 cm, 295 seedlings/m² emerged of which about half survived to maturity in July. Seeds were dispersed from mid-June to November and 136,460/m² were returned to the soil, representing a 14-fold increase in the seed bank. Application of soil-acting herbicides reduced the numbers of weeds and the total seed output, but that of tolerant species was increased. Maximum numbers of seeds were 59,980/m² for Chenopodium album, 39,430/m² for Sleltaria media and 37,580/m² for Veronica persica.