Plant invasion and management in turf‐dominated waste landfills in South Korea

A floristic survey was conducted in turf‐dominated fields on some waste landfills in South Korea, to quantify the degree of plant invasion in those degraded lands. The dominant species, except turf (Zoysia japonica), were Conyza canadensis, Setaria viridis, Digitaria sanguinalis and Aster tripolium. Mean species number declined linearly with distance from the edge of the turf stands. Biomass of each species ranged between 0.1 g and 122.6 g, decreasing linearly with distance from the edge of the stand and declining exponentially with turf coverage. Mean soil moisture storage and organic matter content were 12.59 per cent and 5.81 per cent, respectively. Sum of relative cover, frequency and biomass of all species with environmental variables (distance from the stand edge, turf cover, soil moisture storage, soil organic matter content and the ratio of species number of exotic plants to that of native plants) were ordinated by DCA (detrended correspondence analysis). The first axis of the DCA was positively correlated with distance from the stand edge and turf cover and the second axis of the DCA was negatively correlated with soil organic matter content. Highly and lowly invasive species were indicated from DCA results. From analysis of dispersal type, barochore and anemochore were the most widespread of other dispersal types but it was suggested that anthropochore played an important role in plant invasion in these degraded wastelands. Establishment of an edge transition zone, enhancement of turf cover and reduction in traffic is recommended as management options for turf fields. Copyright © 2002 John Wiley & Sons, Ltd.     

兴凯湖与小兴凯湖鱼类组成及差异分析

兴凯湖与小兴凯湖地处我国东北边陲,仅一岗之隔,但二者的生态环境差别很大,在小兴凯湖移植大银鱼Protosalanx hyalocraniu进行人工增殖没有取得很好效果的情况下,随泄洪水流入到兴凯湖中的大银鱼则很好地发展了自己的种群。为探讨兴凯湖与小兴凯湖鱼类组成的差异及其与大银鱼种群发展的关系,于2010年1月-12月...     

南京市草坪夏季杂草分布特点及防除措施研究

用样线法调查了南京市绿色草坪共２７个样点的杂草发生及分布情况,并用系统聚类法分析比较了各草坪杂草群落的发生及分布特点。调查结果表明,南京市草坪杂草的发生和分布与草坪所处地理位置,土壤水分条件及管理水平有密切关系;其中,地理位置是草坪杂草分布差异的间接原因,杂草种类的多少及每种杂草的数量与管理水平有直接的关系。     

Correlated effects of exotic pollen‐fertility restorer genes on agronomic and quality traits of hybrid rye

In CMS (cytoplasmic male sterility)‐based hybrid rye (Secale cereale L.) breeding, effective pollen‐fertility restoration is an essential prerequisite for achieving maximum grain yield on the one hand and for minimizing ergot (Claviceps purpurea) infestation on the other. Restorer genes for the CMS‐inducing ‘Pampa’ cytoplasm derived from landraces collected in Iran and Argentina are used by breeders for achieving this goal. Here, restorer genes from four germplasm sources (‘Altevogt 14160’, ‘IRAN III’, ‘Trenelense’ and ‘Pico Gentario’) were analysed by producing three‐way cross hybrids between an elite CMS single cross and pollinators with and without a given restorer gene. Materials were evaluated on large drilled plots for restorer index (RI), grain yield, plant height and other traits in six environments. In experiment 1, a restorer gene from ‘Altevogt 14160’ was used. Seven pairs of marker‐selected carrier and non‐carrier backcross lines served as pollinators. In experiment 2, the pollinators were 17 backcross line pairs from the other three germplasm sources. These lines were grouped as high (RI > 67%) and low restorers (RI < 30%), respectively, using testcrosses with a highly diagnostic CMS tester. Hybrids carrying an exotic restorer gene suffered from a significant grain yield reduction by 4.4% and 9.4% and were 9.3 and 4.8 cm taller in experiments 1 and 2, respectively. Thousand‐kernel weight was reduced, whereas quality traits were only slightly affected. For all traits, significant genetic variance existed among the testcrosses to the presence vs. absence of a given exotic restorer gene. This offers a chance for the breeder to reduce or ultimately overcome the presently observed performance reductions brought about by exotic restorer genes.     

4种杂草浸提液对柳枝稷种子萌发的化感作用研究

采用室内生物测定法,研究不同浓度梯度下白草(Pennisetum flaccidum)、赖草(Leymus secalinus)、硬质早熟禾(Poa sphondylodes)和猪毛蒿(Artemisia scoparia)地上部分和根系浸提液对柳枝稷(Panicum virgatum)种子萌发的化感作用,以期为揭示柳枝稷与本土杂草之间的相互作用机制提供借鉴意义.结果表明:不同浓度的白草、赖草和硬质早熟禾浸提液处理均抑制了柳枝稷的种子萌发和幼苗生长,尤其是对发芽指数、胚芽长度和幼苗生物量的影响较大.同时,地上部分浸提液的抑制作用强于根系.在0.1 g/mL白草、赖草和硬质早熟禾地上部分浸提液处理下,柳枝稷胚芽长分别降低了81.13％、86.42％和90.19％.猪毛蒿浸提液在低浓度下抑制作用较小,甚至提高柳枝稷胚根和胚芽长度,表明其浸提液中某些化感物质起到促进作用.4种杂草浸提液在0.1 g/mL浓度下的综合化感效应值分别高达-5.89,-6.17,-5.17和-6.15.综上所述,不同杂草对柳枝稷的影响存在明显差异,生产实践中要根据不同物种和密度采取相应防治措施,以保证柳枝稷良好生长.     

稻田株间除草弹齿齿形及安装方式分析与试验

水田机械除草技术是提高稻米品质的一项重要生产技术,在水稻生长过程中进行机械除草作业,既去除杂草同时又实现了稻田的中耕管理,降低了长期以来化学除草带来的负面环境影响。目前,稻田机械除草技术在对行间杂草去除方面的研究较为成熟,株间杂草去除成为重点的研究方向。为此,设计了一种株间除草关键部件(即除草盘),并对除草盘上弹齿齿形进行了选型,对弹齿安装方式进行分析。按照确定的结构制造了除草盘,进行了室内土槽试验,表明该种形式的除草盘具有较好的除草效果。     

水稻秸秆-薄膜连续叠加覆盖对三叶鬼针草的控制效果

入侵植物三叶鬼针草(Bidens pilosa L.)严重危害我国农林畜牧业的生产。为探究生态高效控制三叶鬼针草的方法,开展了水稻秸秆与塑料薄膜相结合覆盖控制入侵杂草的研究。试验在以三叶鬼针草和马唐[Digitaria sanguinalis(L.)Scop.]为主的自然杂草荒地进行,设置不同稻秆覆盖量(0kg·m~(-2)、1kg·m~(-2)、1.5kg·m~(-2)),于冬季进行稻秆覆盖,春季在稻秆覆盖的基础上覆盖薄膜。通过测定秸秆覆盖中期(2月12日)和薄膜覆盖中期(4月12日)的午间土壤温度、土壤相对含水量和近地表空气温湿度等环境指标和杂草生物量、种子萌发量、杂草群落结构和土壤种子库等群落指标,探究该方法控制入侵杂草的效果和机制。结果表明:冬季水稻秸秆覆盖显著降低了草地午间土壤温度、近地表空气温度、三叶鬼针草生物量和种子萌发量、优势杂草盖度和从属种的种类和数量;覆盖1.5 kg·m~(-2)稻秆的处理对各类指标的影响程度均大于1 kg·m~(-2)的处理。春季叠加薄膜覆盖导致浅层土壤高温干燥、近地表空气高温高湿;叠加薄膜覆盖处理使三叶鬼针草的土壤种子密度在0～5cm的土层内显著低于未做覆盖处理的对照,降低了79.49%;叠加薄膜覆盖处理的入侵杂草全部死亡且无种子萌发。说明冬季采用水稻秸秆覆盖,春季再叠加覆盖薄膜能有效防控三叶鬼针草的生长蔓延,在薄膜覆盖之前,覆盖1.5 kg·m~(-2)稻秆的处理对三叶鬼针草的防控效果要好于1 kg·m~(-2)的处理,在薄膜覆盖处理后,两个稻秆覆盖量处理对三叶鬼针草的防控效果均达到100%。本研究结果可为不同季节采用不同的控制方法及其组合模式防控入侵杂草的扩散提供参考。     

稻作区灌溉水流传播的杂草种子与稻田土壤杂草种子库的关系

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。     

15%精喹禾灵乳油除草剂防治油菜田野燕麦初探

油菜田野燕麦危害严重,于油菜2~4叶期使用15%精喹禾灵乳油450~750ml.hm-2,对水225kg喷施,防除野燕麦效果达90%以上,对油菜安全,灭草后增产显著。     

春播紫花苜蓿苗期杂草的化学防治研究

紫花苜蓿(Medicago sativa L.)苗期杂草危害严重,显著影响建植,为此采用单因素完全随机区组设计的方法,探究7种除草处理对苜蓿产量、品质和杂草防除效果的影响。结果表明:2,4-DB、苯达松及其混用组合处理可有效防除阔叶类杂草,株防效在75.80%～90.65%之间;高效盖草能、精喹禾灵、烯草酮可有效防除单子叶杂草,株防效高于71.10%。喷施2,4-DB会使苜蓿的总产量减少64%以上;喷施苯达松+高效盖草能、苯达松+精喹禾灵、高效盖草均能显著地提高第2茬的产量,苜蓿总产量分别提高45.60%,45.28%和43.06%。综合考虑除草剂的安全性和除杂增产效果等方面,以苯达松+高效盖草能和苯达松+精喹禾灵2种除草处理的效果较好,可在苜蓿生产田推广利用。