Emergence and longevity of seeds of annual weeds in cultivated and undisturbed soil.

Published online
01 Jan 1975
Content type
Journal article
Journal title
Journal of Applied Ecology

Roberts, H. A. & Feast, P. M.

Publication language


In three experiments, begun in successive years, seeds of twenty species of annual weeds were mixed with 15 cm of soil confined in cylinders sunk in the ground outdoors. The soil was either cultivated or left undisturbed, seedling emergence was recorded for 6 years, and each year determinations were made of the numbers of viable seeds remaining.The numbers of viable seeds of individual species and of the population as a whole decreased exponentially. In cultivated soil, the mean decrease was equivalent to 32% per year (half-life rather less than 2 years), with a range from 20-26% (Matricaria matricarioides, Tripleurospermum maritimum spp. inodorum, Fumaria officinalis and Papaver rhoeas) to 44-48% (Senecio vulgaris, Veronica hederifolia and V. persica). In undisturbed soil the mean decrease was 12% per year (half-life 6 years), with a range of individual species of 6-21%. The mean numbers of seeds remaining viable after 6 years amounted to 5.9% of those initially added to cultivated soil and 27.5% where the soil was not disturbed. The species with the highest proportion of seeds still viable after 6 years in undisturbed soil were Chenopodium album (53%) and Thlaspi arvense (48%).The species differed in the extent of initial seedling emergence, its distribution through the year, and in the total numbers of seedlings that emerged. Under a consistent cultivation regime the numbers decreased exponentially from year to year; in undisturbed soil emergence in each of the last three years amounted to only 1.3% of the seeds originally addded.With all species a proportion of the seeds was not accounted for either as seedlings or as viable seeds after 6 years. This ranged from 20 to 60% in cultivated soil and from 33 to 70% where the soil was not disturbed. The results are discussed in relation to previous work on the dynamics of populations of weed seeds in the soil. From summary.

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