Seed banks in seams of curbside in Route 4

Abstract

The present study was conducted to investigate seed banks, which are a source of weed seeds, in seams of curbside by the side of Route 4 from Oyama City in Tochigi Prefecture to Shichinohe Town in Aomori Prefecture. Weed vegetation on the verges and around the roads was surveyed at 24 points from June 6 to 9 and from September 22 to October 4, 2007. Soils were also sampled from the verges at the same time. After the soils were air-dried and passed through a φ5 mm sieve, the weed species and the number of seeds were examined. Seed viability was measured by the press method using forceps.
The results obtained from the study are summarized as follows:1) seed banks were formed in all verges of the road, 2) Seeds of Digitaria ciliaris, Setaria viridis, Taraxacum spp., and Oxalis spp. were abundant in the soil samples, 3) although Plantago asiatica and Artemisia princeps were dominant in the verges, no seeds of either weed species were found in the soils, 4) sources of seeds detected in the soil samples differed according to weed species. For example, seeds of Digitaria ciliaris are supplied from the vegetation of the verges and/or the roads around, whereas many seeds of Sonchus asper are carried over long distances by the wind, and 5) seed viability was high (more than 60%) in Cerastium glomeratum, Oxalis spp., Arenaria serpyllifolia, Poa pratensis, and Senecio vulgaris and low in Digitaria ciliaris and Taraxacum spp.