Abstract: In order to study the correlation between soil weed seedbank and weed seed dispersed by irrigation water,three plots of paddy fields with an irrigation system in a typical rice-growing region was chosen to observe weed community and seedbank both in surrounding habitats and paddy field.The species and number of weed seeds that dispersed by irrigation water were recorded and counted,the weed communities on the ridge of the paddy field and in surrounding habitats of the ditch were surveyed,and they were compared with those in wheat field of next season.The weed seeds of 21 species belonging to 14 families(mainly Gramineae,Primulaceae,Polygonaceae,and Chenopodiaceae)could be dispersed into the paddy field by irrigation water.Seeds of 41 weed species belonging to 19 families were found in the soil weed seedbank of paddy field.The similarity among weed species dispersed by irrigation water,weed communities on the ridge of the paddy field and in the surrounding habitats of the ditch,successive weed communities in wheat field and soil weed seedbank in paddy field was considerablely high with Sorensen similarity indexes all above 0.5,suggesting that weeds were dispersed among them by irrigation water.

Key words: weed seeds, dispersal, soil weed seedbank, irrigation water, similarity index

摘要： 选择典型稻作区，对灌溉水流传播的杂草种子的种类和数量进行取样调查，并与田埂、灌溉水渠周围生境、下茬麦田的杂草群落及稻田土壤杂草种子库进行比较分析，以研究自然条件下灌溉水流传播的杂草种子与土壤杂草种子库及其他生境杂草群落间的相互关系。 有14科21种杂草种子随灌溉水流输入稻田，这些杂草种子主要隶属禾本科、报春花科、藜科、蓼科等。土壤杂草种子库中共检出19科41种杂草种子，含有所有其他生境中杂草的种子。灌溉水流传播的杂草种子与田埂上、灌溉水渠周围生境、下茬麦田杂草群落及稻田土壤种子库的杂草群落间相似性较高，Sorensen指数均在0.5以上。

关键词: 杂草种子, 传播, 土壤杂草种子库, 灌溉水流, 相似性指数