摘要：

In field trials at Helsinki in 1969-70 and at Jokioinen in 1974-9, weed emergence was studied in spring cereals, sugarbeet and fallow land. There were 2 peaks of emergence in May/June and in mid-summer. Galeopsis spp. and Polygonum spp. emerged quickly in early summer. Fumaria officinalis, Chenopodium album and Stellaria media emerged between the end of May and July. Emergence of Viola arvensis...

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