Generative reproduction of weeds on winter rye stubble fields
Jedruszczak, M.(Akademia Rolnicza, Lublin (Poland). Katedra Ogolnej Uprawy Roli i Roslin)
Generative reproduction abilities of weeds and their phenological development were investigated on rye stubble-fields on sandy soil in Uhrusk (Poland). Observations were carried out on 5 neighbouring fields in 10-day intervals from 21 July to 9 Sept. 1983, from rye harvest to stubble cultivation. An investigated weed community comprised 26 species: 22 short-lived and 4 perennial ones. Mean density of weed individuals amounted to 78.8 /square m, over 96 percent of them belonged to short-lived species the most abundant of witch were Setaria glauca and Scleranthus annuus. Fruit and seed bearing and shedding of diaspors developmental stages prevailed with short-lived species while vegetative stages - with perennial ones through the whole research period. The reproduction as well as shedding took place all time, increasing with time the mean number of ripened diaspors per plant, counting totally all community species, multiplied over twice after 20 days and almost twenty-seven times after 50 days in relation to the figure established just at rye harvest. Developing weeds were able to deliver an average 197 mln diaspors per 1 ha into soil on rye stubble-field
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