Type and time of autumn tillage with and without herbicides at reduced rates in southern Sweden: 2. Weed flora and diversity

The design of integrated weed management (IWM) systems is essential in order to reduce the use of herbicides for crop production. By combining different weed management practices, herbicides may be used at lower doses than normally recommended, while still maintaining acceptable weed population levels. The purpose of this study was to develop tillage strategies, with and without herbicides at reduced rates, appropriate for different weed populations. The influences of type and time of stubble cultivation, harrowing and mouldboard ploughing on the weed flora were followed during 1988–1994 in eight long-term field trials situated in southern Sweden. Spring-sown barley (Hordeum distichon L.) and oats (Avena sativa L.) dominated the crop rotations. Herbicides were either omitted or used at ca. 50% of a full dose. The perennial species Sonchus arvensis L. was favoured by omittance of ploughing but was better controlled by late ploughing not preceded by stubble cultivation; the reduction in the latter treatment being 74%. Stubble cultivation succeeded by ploughing reduced biomass of Elymus repens (L.) Gould. by 90% compared with ploughing solely. Early ploughing reduced the biomass of the species by 50% compared with late ploughing. The species Cirsium arvense (L.) Scop. was highly favoured by early ploughing followed by late autumn harrowing, the biomass of the species being six-fold higher than in other treatments. Compared with other treatments, stubble cultivation favoured four annuals but efficiently controlled three others, while omittance of ploughing favoured six annual and two perennial weed species. Late ploughing not preceded by stubble cultivation favoured four annual and one perennial species, while early ploughing was more efficient than late ploughing in controlling two of the annual species. Influences of treatments on weed species were frequently moderated by interspecific competition resulting in inconsistent response at different sites. Herbicides reduced the number of species by three, from 11 to eight species, averaged across sites and tillage systems. Influences of treatments on diversity were not consistent, since weed floras differed between sites and since some of the species responded inconsistently to tillage and herbicides. This study shows that by utilizing appropriate tillage strategies it is possible at many sites to maintain acceptable weed population levels, although herbicides are used at 50% lower doses than is normally recommended. The timing and type of tillage have to be chosen for being as efficient as possible to the most troublesome weed species at a site.     

日本结缕草草坪中杂草的发生与防治研究

经１９９５ ～１９９８ 年对日本结缕草草坪中杂草发生规律及其防治体系进行了初步研究,研究结果表明,一年四季草坪中均有杂草发生,但主要以２ ～６ 月和９ ～１２ 月为主,并根据杂草的发生情况,建立了以化学除草为主的防除体系,提出了适宜的除草剂种类、剂量以及用药时间和方式。     

Plant protection in spring cereal production with reduced tillage. II. Pests and beneficial insects

In five field experiments run for four years the infestation of pests and the activity of carabids and staphylinids were compared in autumn ploughed and reduced tillage (no-tillage or spring harrowing) plots. Differences were generally most evident in experiments with no-tillage. Weed cover was denser in reduced tillage, and could explain much of the differences. The agromyzid Chromatomyia fuscula was most common in autumn ploughed plots, probably due to healthier plants. Thrips numbers were correlated with grain quality in no-tillage plots. Field slugs were most common in reduced tillage, and were positively correlated with weed cover. Generally, more carabids and staphylinids were caught in reduced tillage. This was especially true for Amara-species and Loricera pilicornis, Philonthus cognatus and Tachinus signatus, which also were positively correlated with weed cover. Aloconota gregaria, Bembidion quadrimaculatum, B. lampros, Harpalus rufipes and Trechus quadristriatus were more common in autumn ploughed plots, several of them preferring open soil.     

关中西部麦田杂草分布及危害损失

调查结果表明,陕西省关中西部麦田杂草主要有２２种,分属１０科２２属,危害严重的有１０种。６个生态区杂草种类,优势组合分布特点有一定差异,尤以地灌区与塬区旱地存在较大差异。影响杂草分布的因素 地理条件外,还有人为传播,耕作栽培,降雨量,化学除措等。     

乙草胺与吡嘧磺隆混用防除稻田杂草药效试验报告

本试验采用乙草胺与吡嘧磺隆混用防除稻田杂草,经过１９９４～１９９５年小区试验,筛选出防除稗草、野慈菇和萤蔺等一年生及多年生杂草的最佳配比;１９９６年进行了大区药效试验,防除效果达９０％～９５％。成本低于丁草胺与吡嘧磺隆混剂。     

两种新型除草剂对麦田恶性杂草防除效果

推广使用高效、安全的麦田除草剂是控制节节麦等麦田恶性杂草严重发生的经济有效的措施之一，本试验采用田间试验方法研究了AEF1300603OF(3％世玛油剂)及WG13A13．6WG对麦田恶性杂革的防治效果。试验结果表明，WG13A13．6WG对麦田杂草防除效果显著，其最佳用量为25～35g／667m^2。在小麦返青期，对节节麦防效达85％～95％，对蜡烛草的防效达85％～90％，对播娘蒿、荠菜的防效达100％，对猪殃殃、婆婆纳等抗性较强的杂革防效也在90％～100％，均高于AEF1300603OF的防除效果。收获首田间调查发现防效趋势与首期调查结果一致。而且WG13A13．6WG防除杂草后使小麦的增产幅度在16．27％～25．48％。     

48%烟嘧·莠去津可湿粉防除春玉米田杂草药效试验

应用48%烟嘧·莠去津可湿粉防除春玉米田杂草,试验表明,混配药剂对玉米正常生长,无药害状,在试验剂量内对作物安全性好。     

茶园虫病草防治存在的问题及对策

作者根据五十余年茶树植保工作实践总结茶园虫、病、草发生的三个共同特点及防治中存在的问题,提出5个方面的决策和相应的30余条具体措施.     

施田补对胡萝卜田杂草的防治效果研究

[目的]探究施田补在青海西宁地区胡萝p田的使用效果并筛选最佳使用浓度。[方法]通过小区试验设计研究了不同浓度（500、1000、1500、2000和2500倍液）施田补对胡萝卜生长的影响及对田间杂草的防治效果。[结果]对胡萝卜田喷洒33％施田补1500倍液有显著的除草效果，增产效果达25％以上，不同时期的灭草率在92％以上，且使用安全。[结论]施田补可在西宁地区胡萝卜田推广使用。     

Participatory evaluation of mechanical weeders in lowland rice production systems in Benin

Weeds are a major constraint to rice (Oryza sativa) production in sub-Saharan Africa. Use of mechanical hand weeders could reduce the labor required for weeding. This paper uses a participatory approach to examine the suitability of six mechanical weeders in Benin. A total of 157 farmers (93 male, 64 female) in 14 villages tested the mechanical weeders, ranked them in order of preference, and compared them with their own weed management practices. The ring hoe had the highest rank, followed by the straight-spike weeder; 97% of the farmers preferred the ring hoe to their own weed management practices, by hand or using traditional hoe, because of its easy operation and high efficiency. The ring hoe tended to be preferred especially in the fields with non-ponded water and relatively higher weed pressure. The straight-spike weeder tended to be preferred to ring hoe in the fields where weed pressure is less, whereas in ponded conditions, farmers liked these two weeders in equal proportion. The preference of weeders was not related to gender, rice field size, or years of experience of rice cultivation. Among 23 farmers who used herbicides, 17 farmers preferred herbicides to the ring hoe and have rice field of >0.5 ha. Mechanical weeders can offer an effective approach for weed management, especially for small-scale rice farmers, and different types of mechanical weeders should be introduced to farmers based on water regimes and weed pressure level.