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在田间条件下,采用替代试验对比研究了3种1年生牧草——高丹草、紫花苜蓿和欧洲菊苣与入侵我国华北地区的一种外来植物黄顶菊之间的相对竞争表现;通过设置不同牧草与黄顶菊组合的替代比例(牧草与黄顶菊分别单种及1∶1、1.5∶1和2∶1比例混种),建立了3种牧草与黄顶菊的田间替代试验区。结果表明:随着3种牧草替代比例的增加,其盖度也逐渐上升,均对黄顶菊表现不同程度的抑制,其中高丹草出苗较黄顶菊更早且具有更强的遮阴能力,在各混种替代组合中完全抑制了黄顶菊生长,抑制率达100%;紫花苜蓿和欧洲菊苣与黄顶菊的混种种群中,黄顶菊的生物量、株高等均极显著低于对照,且在中等替代比例(1.5∶1)下对黄顶菊的抑制效果为最佳,抑制率分别为87.7%和96.2%;在与3种牧草竞争的条件下,黄顶菊相对产量均显著<1.0,表明黄顶菊种间竞争显著小于种内竞争,使该外来种生长受到有效抑制。在黄顶菊已入侵和易于入侵的生境建立牧草替代种群是进行生态重建和保持当地生物多样性的有效手段。
Under field conditions, the comparative experiments were conducted to study the relative competitive performance of three perennial grasses-sudangrass, alfalfa and European chicory with the invasive plant Flaveria bidentis in North China. The alternative proportion of the combination of forage flavescens and flaveria bidentis (forage mixed with flaveria bidentis, respectively, at a ratio of 1: 1, 1.5: 1 and 2: 1) was established. The results showed that the coverage of three species of forage was gradually increased with the increase of the proportion of three kinds of forage, which all inhibited the growth of bumble bee. The emergence of sudangrass was earlier and more shading ability than that of the flint, In the alternative combinations, the growth of flaveria bidentis was completely inhibited and the inhibition rate was 100%. The biomass and plant height of Flaveria bidentis were significantly lower than those of the control in the mixed population of Medicago sativa and European flax, : 1), the inhibition rate was 87.7% and 96.2%, respectively. The relative yield of Flaveria bidentis was significantly lower than 1.0 under the conditions of competition with three species of forage grass, indicating that the interspecific competition between Flaveria bidentis was significantly less than that within the species Competition, so that the foreign species growth is effectively inhibited. The establishment of alternative herds of forage in habitats in which invasive and vulnerable invasions of flaveria bidentis is an effective means of ecological restoration and preservation of local biodiversity.