Seedling Appearance, Survival and Flowering of <i>Trifolium pratense </i>in a Cutting Meadow

Abstract

Seedling appearance, survival and of Trifolium pratense from naturally deposited seeds in meadow soil layers were monitored over a period of 8 years in a meadow for herbage (hereafter referred to as cutting meadow) in the central mountainous district of Japan. In the meadow, Phleum pratense predominated and herbage had been harvested for making hay or silage in early June and late August of a year since the establishment of the meadow in 1966. T pratense seedlings appeared from March to May (namely spring cohort) and from September to November (namely autumn cohort) every year. Estimated seedling density ranged yearly from 18 to 1,215 secdlings/m 2 in the spring cohorts and from 1 to 245 seedlings/m 2 in the autumn cohorts, with an average of 199 and 86 seedlings/m 2 , respectively. Half-life ranged yearly from 4 to 63 days for the spring cohorts and from 33 to 248 days for the autumn cohorts, with an average of 42 and 135 days, respectively. Of the 13,485 seedlings marked, no individuals survived for more than 4 years. Most of the individuals undergoing (hereafter referred to as flowering individuals) originated from the autumn cohorts. Thirty-two percent of the survivors began to flower in the first summer after their appearance. Ratio of individuals to survivors rose to 81% in the second summer and fell to 50% in the third summer. It was suggested that during mechanical operations for harvesting in late August, T pratense seeds were dropped and that the lack of third harvesting prolonged the half-life of the autumn cohorts which had succeeded in reproducing in this meadow.