老挝丰沙里省小粒咖啡园杂草发生情况及其群落结构

为探究老挝丰沙里省小粒咖啡园杂草的发生危害情况,笔者于2016—2017年采用倒"W"形9点取样法对老挝丰沙里省6县小粒咖啡园进行调查研究。确定了该地区小粒咖啡园杂草有79种,隶属于23科66属,其中相对多度在10%以上的有11种杂草。白茅、粽叶芦、飞机草、胜红蓟、马唐、蕨、牛筋草、鬼针草、小飞蓬、藜和铺地黍是构成老挝丰沙里省小粒咖啡园杂草群落的优势杂草。研究结果将为老挝丰沙里省小粒咖啡园的杂草防控提供重要参考。     

保山小粒咖啡园杂草种类及危害现状

杂草是制约咖啡生长和产量稳定的关键因子,系统性了解咖啡园杂草种类及危害现状,对小粒咖啡园杂草的科学防控具有积极作用。2019—2022年对保山小粒咖啡产区杂草种类及危害进行系统调查,共发现杂草37科86属97种,其中,外来杂草15种,危害较为严重的杂草有白羊草(Bothriochloa ischaemum)、鬼针草(Bidens pilosa)、藿香蓟(Ageratum conyzoides)、小蓬草(Erigeron canadensis)、紫茎泽兰(Ageratina adenophora)、香附子(Cyperus rotundus)、反枝苋(Amaranthus retroflexus)及饭包草(Commelina benghalensis)。建议采用人工、物理、机械及生态除草的方法进行杂草综合防控,禁止使用化学除草。     

四川省杂草稻发生危害初步调查与防除研究

2010年和2011年对四川省水稻主产区的杂草稻发生危害情况进行了初步调查.结果表明,除德阳市绵竹市新市镇局部地区杂草稻发生危害较重(危害级别4级)外,全省范围内杂草稻发生危害较轻,危害级别以1级为主.同时,在杂草稻发生危害调查的基础上,进行了化学除草剂初步筛选试验.结果表明,供试药剂中只有扫茀特对杂草稻有效,药后30 d和60 d的防效均在50％以上.     

北京市麦田杂草群落演替与防除技术

2007年对北京市麦田杂草种类及危害进行了调查,通过与1990年的调查资料对比,发现麦田杂草种类和杂草群落组合发生了明显变化.局部地区禾本科杂草发生与危害严重,应加强对禾本科杂草的监控和防除.     

我国杂草稻危害现状及其防控对策

随着直播稻和稻麦免、少耕技术的推广,杂草稻在我国的危害越来越重,已严重影响水稻产量和稻米质量.笔者分析了稻田杂草稻的发生危害原因,提出了采用高纯度的种子,从源头上防止杂草稻蔓延和侵入危害;及时清理收割机等农机上携带的杂草稻种子,防止杂草稻的传播;翻耕、诱杀以及手工拔除,轮作、直播改移栽水稻栽培方式;使用化学除草剂防除等综合防除技术.     

重庆市农田杂草发生现状及治理对策

通过对重庆市农田杂草发生现状的调查,阐述农田杂草的危害,结合目前农村化学除草剂的应用情况,提出农田杂草的控制技术和综合治理思路.     

泰州市杂草稻的发生规律和防控技术

杂草稻是水稻生产的恶性杂草之一.由于轻型栽培模式的推广,发生和危害逐渐扩大.通过系统调查和研究,总结了江苏省泰州地区杂草稻的发生规律,分析了发生原因,实施了有效综合防控技术.     

大豆田杂草防除策略的探讨

制定合理的大豆田杂草防除策略,有效地控制杂草危害,对大幅度增加大豆产量,改进品质,提高生产效益至关重要。合理的杂草防除策略应建立在对杂草发生和危害规律的正确认识上,现根据已有的研究结果,仅就黑龙江省大豆田杂草防除策略提出如下看法,供进一步研究探讨。 (一) 黑龙江省大豆田杂草的发生和危害根据我们调查,黑龙江省大豆田杂草以一年生杂草为主,其中稗草危害最严重,其发生频率和危害指数均居首位。其次是藜、蓼、苋、鸭跖草和狗尾草,再次是苍耳和香薷,野燕麦在部分地区危害也很严重。多年生杂草以苣荬菜和问荆的发生频率和危害指数最高。     

麦田杂草发生现状及治理对策

对2001-2011年安新县麦田杂草田间发生情况进行了全面总结,明确了麦田杂草发生演变情况及当前发生现状,并进行了原因分析,有针对性地提出了防治措施,以期对有效控制麦田杂草发生危害提供参考。     

苏州城区公共草坪杂草发生与化学防除试验

采用五级草害目测调查法对江苏省苏州市区公共草坪绿地杂草发生危害进行调查,结果表明,苏州城区草坪绿地杂草发生危害较为普遍.调查记录到草坪绿地害草种类67种,草害发生量6.3株/m2,相对多度7.9％,相对盖度10.4％,相对高度和发生频率均为100％,杂草总的危害等级达到4级以上.造成危害的主要杂草种类有14种,区域性发生危害的杂草有15种.对三叶草草坪的禾本科杂草危害,可采用高效氟吡甲禾灵或大杀禾防治,除草效果可达90％以上.对狗牙根或高羊茅草坪阔叶杂草危害,可采用2甲4氯、氯氟吡氧乙酸、二氯吡啶酸等的其中一种进行化学防治,除草效果可达85％以上;但因草坪草害群落中发生的杂草种类不同,在选择除草剂品种时也应有针对性,或在处理时添加SD助剂以提高除草效果.     

Changes in agronomic practices and incidence and severity of diseases in winter wheat in England and Wales between 1999 and 2019

In continuation of the annual national surveys of winter wheat, which began in 1970, samples from between 250 and 350 randomly selected wheat crops in England and Wales between 1999 to 2019 were visually assessed for disease symptoms during the milky ripe development stages (GS 73–75). Septoria tritici blotch was the most prevalent and severe foliar disease each year, although annual levels fluctuated considerably and there was no overall significant change over the two decades. Incidence of brown rust, yellow rust, take-all, and barley yellow dwarf virus also showed no significant overall change during the survey period, whereas glume blotch, powdery mildew, eyespot, and sharp eyespot all showed significant decline. Fusarium ear blight has significantly increased in both incidence and severity, causing a serious epidemic in 2012, when 96% of crops were affected. Tan spot has been the third most prevalent foliar disease since 2009 although severity is still very low. Regional disease levels were consistent over the two decades, providing reliable baselines to measure changes in seasonal disease severity. There were significant changes in agronomic practice with a rise to predominance of minimum tillage over the use of ploughing, decreases in overall disease susceptibility of cultivars grown, a major increase in the use of oilseed rape in the rotation and a long-term trend towards earlier sowing. Fungicide use increased considerably, with over 98% crops sprayed and an average of 3.5 applications made per crop each year since 2014. Implications of changes over the last 21 years are discussed.     

中国的沙暴、尘暴及其防治

沙尘暴在进入 90年代以来有进一步加剧趋势 ,其原因在于此期我国西北地区气候干暖化态势明显 ,人类超负荷开发资源加剧 ,从而导致沙尘暴的频繁发生 ,但总体上仍属于正常的灾害现象。我国沙暴只能发生于干旱半干旱区 ,尘暴则可波及半湿润与湿润区 ,由此而论 ,北京的沙尘暴属于尘暴范畴 ,北京不会形成沙漠区。防治沙尘暴必须采取水、土、植被综合防治措施 ,基本对策是 :1 .搞好流域为单元的水土资源合理利用规划 ,进行水土保持综合防治 ;2 .增加地表植被复盖 ,搞好防护林体系建设 ;3 .减轻土地利用强度 ,恢复提高土地抗蚀能力 ;4.加强管理体系建设 ,依法建设生态环境。建议国家设立水土保持为主要职能的生态环境建设委员会 ,统一协调布署我国的生态环境建设工作。     

吡虫啉和百菌清在设施内外葫芦和黄瓜中的残留特性比较

采用高效液相色谱和气相色谱法,分别研究了吡虫啉和百菌清在薄膜大棚设施内外葫芦叶和黄瓜中消解动态及其在葫芦和黄瓜中的残留量,并结合气象因子对产生残留差异的原因进行了分析。样品中的吡虫啉经乙腈和盐酸溶液提取,中性氧化铝和弗罗里硅土层析柱净化后,用高效液相色谱检测;百菌清经乙腈提取,中性氧化铝层析柱净化后,用气相色谱检测。结果表明:吡虫啉在设施内外葫芦叶和黄瓜中均消解迅速,施药7 d后,其在设施内外葫芦叶上的消解率分别为90.4%和98.7%,在黄瓜中的消解率分别为67.8%和85.9%;而百菌清在葫芦叶上的消解速率均比在黄瓜中的稍慢,施药7 d后其在设施内外葫芦叶上的消解率分别为15.4%和38.1%,在黄瓜中的消解率分别为87.8%和91.5%。表明2种农药在设施外2种蔬菜上的消解速率均快于设施内的。两种农药均是在设施外葫芦及黄瓜中的残留量低于设施内的,而降雨和光照强度可能是引起农药在设施内外蔬菜上残留差异的主要因子。     

2017年与2014年西安极端高温天气及其环流特征对比分析

借助观测资料与FNL全球分析资料，对比研究2017年与2014年西安高温天气基本特征与有利环流形势，结果表明：① 2 a西安均发生了40 ℃以上的长时间持续高温天气，其中2014年属于常规高温年份，而2017年西安高温则提前1个月发生，高温的提前发生主要是因为南亚高压强于正常年份同期强度；② 不同于我国南方地区的闷湿高温，西安高温属于干性高温，且昼夜温差较小，由此造成24 h对人体的不适；③ 详细描述了西安高温发生的典型环流特征，即南亚高压与西太平洋副热带高压（简称副高）同时增强，并在对流层中高层相互贯通；④ 南亚高压是影响我国西北地区的主要热源基地，在较大经向度的有利环流背景下，强风速可将热气团向南向东深度输送至下游地区（即西安）；⑤ 在“上辐合、下辐散”的散度场配置下，西安500 hPa以下高空维持明显的下沉气流，加之有利的局部要素相配合，最终造成该地区高温天气的发生。     

Plant-pathogen interactions of sunflower and Macrophomina phaseolina in vitro and in vivo

The relative pathogenicity of isolates of Macrophomina phaseolina was comparable both on sunflower tissue cultures and on mature plants and seedlings. The relative susceptibility of the different sunflower lines in vitro showed a similar pattern for cotyledon callus cultures, but not for immature embryo cultures. Although these protocols appear to be unsuitable for the selection of novel disease resistance, they do offer the potential for a rapid, non-destructive screen for resistant material.     

Trends and expectations for research and technology in weed science in Thailand

There are many possible ways to improve the economic crisis in Thailand, and it is agreed that development of agricultural production is ideal for improving the economic situation in an agricultural country such as Thailand. A strategic plan for agricultural and agro‐industry research is included in the national research agenda and can be classified into nine groups covering different research areas. Most research is based on the agricultural production of four main product groups: (i) crops; (ii) aquatic animals/plants and fisheries products; (iii) poultry, livestock and animal products; and (iv) forest resources. Trends in research and development in weed management for crop production will continue to support the food demands and the development of efficient production of quality products.     

Pesticide residues in soil and foodstuff I. Chlorinated pesticides in cattle feed and milk produced in orchard and non-orchard areas

Milk, hay and silage produced in orchard and non-orchard areas have been analysed for their content of chlorinated pesticides. The residue levels in milk produced in orchard areas were about double those in milk produced in non-orchard areas. The levels in hay were much higher (30% up to sevenfold) in the hay produced in orchard areas and the levels in silage from the two areas showed small differences. Milk collected after cattle had been grazing in an orchard for 3 to 4 days contained 10% more pp′-DDT and 2-, 3-, 7- and 15-fold morepp′-DDE, pp′-TDE and heptachlor epoxide, gamma-BHC and pp′-TDE olefin [1-chloro-2,2-bis(p-chlorophenyl)ethylene], respectively, than did the samples collected one day before the cattle grazed in the orchard.     

北京地区明代、清代干旱灾害与气候事件研究

根据北京地区历史时期旱灾资料,利用数学统计方法中的参数区间估计研究了明清时期该地区旱灾的差异和气候的不同。结果表明：在北京地区明代（1368-1643年）276年内,共发生旱灾166次,平均1.66年发生1次;轻度旱灾47次,中度旱灾56次,大旱灾55次,特大旱灾8次。在清代（1644-1912年）的269年里,共发生...