Abstract: Weed abundance and biomass among three perennial grasses(Elymus nutans,Festuca sinensis,and Festuca ovina) cultivated widely in the east Qinghai-Tibetan plateau were studied.Seven different sowing methods and four density levels were used in the experiment.Field quadrats were tracked and investigated for three years.Results showed 30 kinds of weeds in the cultivated grassland during first growing season.Annual broadleaf weeds,such as Trigonotis peduncularis,Chenopodium album,Elsholtzia patrini,and Lamium amplexicaule had considerable impact on the cultivated grassland.In the second growing season,weed abundance was the lowest(19 kinds) among three years.Perennial weeds,such as Chenopodium album、Artemisia tangutica、and Asiatic plantain had impact on the cultivated grassland.In the third growing season,weed abundance was the highest(40 kinds) among three years and Artemisia tangutica,Plantago asiatica,Geranium wilfordii and Humata tyermanni had significant impact on the cultivated grassland.Both F.sinensis and F.ovina exhibited the poorest persistence in the first establishment year then increased in the following seasons,whereas E.nutans showed the best persistence in the first establishment year then decreased in the following seasons.

Key words: Alpine cultivated grassland, Weed abundance, Weed biomass

摘要： 本试验选取青藏高原常见多年生牧草垂穗披碱草(Elymus nutans)、中华羊茅(Festuca sinensis)和羊茅(Festuca ovina)建植人工草地,设计7种播种组合,4个密度水平,通过3年的野外样方调查,分析了人工草地中杂草丰富度和杂草生物量的变化规律。结果表明:人工草地建植当年,共出现30种杂草,其中附地菜(Trigonotis peduncularis)、萼果香薷(Elsholtzia patrini)、白藜(Chenopodium album)、宝盖草(Lamium amplexicaule)等一年生阔叶杂草对草地影响较大;人工草地建植第2年,杂草丰富度最低(19种),对草地影响较大的是萼果香薷、甘青蒿(Artemisia tangutica)、车前(Plantago asiatica)及臭蒿(Artemisia hedinii)等多年生杂草;人工草地建植第3年,草地的杂草丰富度最高(40种),对草地影响较大的有甘青蒿、车前和老鹳草(Geranium wilfordii)以及草石蚕(Humata tyermanni)等多年生杂草。中华羊茅和羊茅草地抵制杂草的能力在建植当年(2003年)最弱,2004年和2005年之后逐渐增强;垂穗披碱草抵制杂草的能力在建植当年(2003年)最强,2004年和2005年以后随着建植时间的增加而逐渐减弱。

关键词: 高寒人工草地, 杂草丰富度, 杂草生物量