北海口岸进口大豆杂草疫情分析及检疫策略

根据2012—2015年北海口岸进口大豆检出杂草疫情的统计数据,对来自5个国家的250批次大豆的杂草检出情况进行分析,结果显示,自2012年以来共截获杂草种子26科173种,其中检疫性杂草5科15种。不同国家进口大豆中检出的杂草种子种类和数量差异较大。针对上述情况,提出了有关进境大豆杂草检疫监管的建议。     

华南地区大豆田杂草种子库特征与化学防除的研究

针对华南地区大豆田杂草防除问题,采用种子库诱萌法和田间药效试验法,研究田间杂草种子库的预测方法,筛选最佳化学防除方案.结果表明:杂草种子库共有杂草7科10属,主要分布在0～ 10 cm的土层,总出草量为6 861株·m-2.田间实际出草种类为6科9属,实际出草量平均为208株·m-2,占土壤杂草种子库总量的3.03％;6种除草剂都具有良好的防除效果,其中7.5％禾阔灵乳油的防除效果最佳,能有效防除禾本科杂草、莎草科杂草以及阔叶杂草,药后45 d鲜重防效仍达到70.7％～72.4％,可使大豆增产20.5％～ 34.5％.     

稻田土壤杂草种子库研究

对江苏省仪征市连年稻麦两熟轮作稻田土壤杂草种子库中杂草种类进行了考查。结果表明, 有11 科22 种杂草的种子主要分布在0～10 cm 土层内。同时, 阐述了土壤种子库杂草种子的来源, 因水分、湿度、光照等自然因素和耕作、人工除草等人为因素, 杂草种子本身的完熟度等综合因素造成了土壤杂草种子库中杂草种子活力的损失与累积, 以及杂草种子萌发与土层深度、水分等的关系, 初步探明了水旱轮作对稻田土壤杂草种子库的影响, 提出了减少杂草种子库种源的对策。     

河泽地区夏大豆田杂草发生及防治技术

１大豆田杂草发生和危害１１杂草多样性荷泽地区位于山东西南部，西北濒临黄河。由于每年洪水沿黄河从黄土高坡流下，在粘壤沉淀的同时，上游大量杂草种子也随泥沙遗留在黄河两岸，因而杂草种类多而复杂。据荷泽市植保站（１９９６）调查，大豆杂草有１０７种，其中以菊...     

大豆与杂草竞争临界期研究初报

草害是造成大豆减产的主要因素之一。本试验通过系统观察大豆田杂草消长规律,对大豆播后不同时期人工除草的保产效果进行了对比试验研究。结果表明:本地大豆田杂草有两个发草高峰,出现时间分别在大豆播后18～30天和37～48天。大豆田杂草防除临界期为大豆播后18～30天,在此期内除草一次,保产效果最佳。     

乐田特(Radiant-S)防除春大豆田杂草效果评价

田间小区试验结果表明，在春大豆苗2片复叶期，禾本科杂草3-5叶期，阔叶杂草株高5-7cm时施药，6.5%乐田特乳油对大豆田的捭草，藜，本氏蓼，反枝苋，龙葵，香薷，卷茎蓼等一年生禾本科杂草和阔叶杂草有良好防效，虽然对大豆叶片可造成接触性药害斑，但在1周后即可恢复正常，不影响大豆后期生长发育和开花结实，对大豆安全，适宜用药量为6.5%乐田特乳油1650-1800ml/hm^2。     

夏大豆田间杂草发生情况及防除措施

由于夏大豆生长期气温高．雨水充足．有利于杂草的发生和生长．近几年．鲁南及鲁西南地区大豆田杂草发生逐年加重,杂草种类多、危害重,一般减产20％～50％,成为制约当地夏大豆产量的主要因素之一。针对这种情况．通过对夏大豆田杂草发生情况、发生特点以及发生原因进行调查分析．并与生产实践相结合,多次进行药剂试验．总结出一套夏大豆田间杂草综合防除技术。     

济宁市区夏播大豆田杂草的发生与防除研究

研究结果表明,济宁市夏播大豆田杂草有8科20种,优势种群为马唐和醴肠。田间有二个出草高峰,一峰在大豆播种后的5~15 d,二峰在播种后的40~45 d。茎叶处理方法防除禾本科和阔叶混生的大豆田杂草,以5%盖草双单1 500 ml/hm2为最好,总株防效和鲜重防效均在86%以上。以禾本科杂草为主的大豆田,以8.8%精喹禾灵600 ml/hm2防效最好,株防效在83%以上。以阔叶杂草为主的大豆田,24%克阔乐450 ml/hm2防效最好,株防效在82%以上。     

杂草疫情分析在大豆产地溯源中的辅助性应用研究

中国是进口大豆主要消费国,近15年,累计进口大豆90 875万t.由于各国大豆品质不一,征税标准不同,国际大豆贸易中的掺假行为日益凸显.为了进一步完善大豆溯源技术,本研究对2005-2019年进口大豆中携带杂草籽的种类、截获频次、来源国等信息进行整合分析,采用主成分分析和聚类分析方法提取累计贡献率高的主成分,并分析各类杂草是否存在地域差异.结果显示:确定杂草种类981种,其中单一来源国杂草251种.主成分分析提取的前2个因子贡献率达95.41％,可反映进口大豆中携带杂草疫情的绝大多数信息.以上述2个因子为分类变量,对综合因子得分前100的杂草进行聚类分析的结果显示,进口大豆携带的部分杂草地域特征明显,杂草种类与地理位置密切相关,按其来源特征可分为一般性杂草、南美区和北美区3类.如圆叶牵牛(Ipomoeapurpurea)等24种杂草在南美洲国家进口大豆中截获率更高,而苘麻(Abutilontheophrasti)等14种杂草在北美洲国家进口大豆中则更加常见,可为进口大豆产地溯源提供辅助性指标,为商品归类属性鉴别业务提供参考依据.     

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。     

Pre and postemergence herbicides for weed control in castor crop

Weed management is among the main factors limiting cultivation of castor (Ricinus communis) in extensive fields, particularly when labor is scarce or expensive. This experiment evaluated the efficiency of weed management programs using preemergence (clomazone, pendimethalin, and trifluralin) and a postemergence herbicide (chlorimuron-ethyl) applied at 20 days after emergence in castor plants cv. BRS Energia under rainfed conditions in Apodi, Brazil. No phytotoxicity was observed on the castor plants, and the postemergence herbicide significantly increased castor seed yield to 1466 kg ha⁻¹ complementing the weed control of preemergence herbicides treatments in which seed yield was 1207 kg ha⁻¹. Seed yield on weedy and weed-free treatments was 760 and 1971 kg ha⁻¹, respectively. Weeds were kept under a satisfactory control up to 40 days after emergence. This program resulted in reasonable weed control because the preemergence herbicides controled monocotyledon weeds, while the postemergence herbicide controlled broad leafed species being selective to castor plants.     

Ecological studies on Echinochloa crus-galli and the implications for weed management in direct-seeded rice

Echinochloa crus-galli, a C₄ grass, is one of the world’s most serious weeds. Weed management decisions for this species can be derived from knowledge of its seed biology. Studies were conducted to determine the effects of light on germination; seed burial depth and rice residue on emergence and growth; and flooding time and depth on emergence, survival and growth of this species. Light stimulated seed germination but it was not an absolute requirement for germination. The proportion of seeds germinating was greatest for seeds placed on the soil surface (92%), and emergence declined with increasing burial depth in soil; no seedlings emerged from the depth of 8 cm. A burial depth of only 0.4 cm reduced seedling emergence by 50%. Seedling emergence and seedling biomass were reduced by the addition of high level (6 ton ha⁻¹) of rice residue to the soil surface. Early and deep flooding significantly suppressed growth of E. crus-galli seedlings. In flooded conditions, with increased water depth the weed allocated more biomass to shoots at the expense of roots. The information gained from this study could contribute to improve weed control approaches. Soil inversion by tillage to bury weed seeds below their maximum depth of emergence, use of crop residue as mulch and early flooding of the crop could serve as important tools for managing E. crus-galli and other weed species with similar germination requirements. These management options, however, would need to be compatible with other crop management requirements.     

北方地区豆田杂草防除技巧

北方春季干旱多大风,严重影响除草剂药效,因此掌握豆田杂草防除技巧对指导豆田杂草防除工作具有十分重大的现实意义.本文阐述了豆田苗前封闭除草和苗后茎叶处理的化学除草技巧,以期为农业科技人员提供防除豆田杂草的理论参考.     

Effect of herbicide application on weed flora under conservation agriculture in Zimbabwe

Increased challenges of weed control in the smallholder farming sector of southern Africa have often resulted in small yields. The objective of this study was to evaluate the effects of different weed control strategies on weed flora and composition under conservation agriculture (CA) systems in Zimbabwe. This study was conducted at three on-station trial sites namely Domboshawa Training Centre (DTC), University of Zimbabwe farm (UZ farm) and Henderson Research Station (HRS) in a maize–soybean rotation for four seasons from 2009–2010 to 2012–2013 seasons. Hand weeding was done whenever weeds were 10 cm tall or 10 cm in circumference for weeds with a stoloniferous growth habit. Weed identification was done up to the weed species level, and the Shannon–Weiner diversity and evenness index was used to determine the response of weed flora to herbicides. Results showed that there were more weeds in the early years which decreased gradually until the final season. Weed species diversity was not affected by herbicide application and the results indicated that weed species diversity was small in CA systems. Annual weed species constituted a greater proportion of species, and species richness decreased with the duration of the study. Richardia scabra L. and Galinsoga parviflora Cav. were the most common dominant weed species at all sites and in all seasons. Moreover, herbicide application had no effect on the evenness of weeds in the plots but site characteristics had a significant effect on the distribution of weed species (weed species evenness). The results presented in this study suggest that herbicide application facilitates a depletion of weed seed bank/number of weeds over time. Thus, herbicide application in CA has potential to reduce weed density, species richness and species diversity in the long term which may lead to more labour savings and larger yields.     

农威豆田防除杂草的安全性试验研究

５％农威ＥＣ是一种低毒、高效、广谱，具有选择性内吸传导型，苗后茎叶处理的豆田除草剂。防除禾本科杂草防效达９５％以上，对阔叶杂草及莎草科杂草防效一般大于８５％，一次性施药，麦茬免耕种植夏大豆，省工省时。按每公顷剂量６７５ｍｌ于傍晚施药，其轻微药害７天后即可恢复，不伤害大豆植株，并增产５－１０％，不污染环境，药效期４０天左右，不影响下茬作物，安全性高，使用方便，在当前农业生产上属少有新品种。     

Sustainable weed management in conservation agriculture

Sustainable crop production is necessary to ensure global food security and environmental safety. Conservation agriculture (CA) is gaining popularity around the globe due to its sustainable approaches such as permanent soil cover, minimal soil disturbance, planned crop rotations and integrated weed management. Weed control is the biggest challenge to CA adoption. Weed ecology and management is different in CA than in conventional agriculture. In CA, weeds expression, seed bank status, distribution, dispersal mechanisms, diversification, growing patterns and competition trends are complex and differ from conventional systems. It is due to reduced tillage of the soil and the flora that thrives in CA. Reduced tillage systems affect the efficacy of herbicides and mechanical weed control measures. So, it is an important task to find out the differences and to fabricate new management options. In this review, changing weed dynamics have been framed. A novel aspect of this review is the comprehensive account of sustainable weed management strategies in relation to CA. Modified tillage operations, improved cultural practices, bioherbicides, chemical herbicides, allelopathy, and crop nutrition have been identified as suitable weed management tools. None of these offers complete control but the integration of these tools in suitable combinations works efficiently. Weeds dominating CA and their responses to CA components are highlighted. For example, small seeded and perennial weeds are more abundant in CA. The role of herbicide resistance in weeds and herbicide tolerant (HT) crops in CA is also highlighted. Allelopathy and crop nutrition are discussed as modern weed management tools for CA. A detailed account of weed responses to fertilizer management options is also given. Integrated weed management compatible to cropping patterns and climatic conditions offers the best results in CA. Future efforts must be directed towards the optimization and integration of these weed management practices.     

Effect of herbicides on weed management in dry-seeded rice sown under different tillage systems

In India, dry-seeded rice (DSR) production systems are rapidly replacing conventional rice production systems due to various advantages. DSR systems can be managed under zero-till (ZT) conditions or after a preparatory tillage, often referred to as conventional tillage systems (CONT). Although previous reports indicate the contribution of tillage to weed suppression, the effect of one-time preparatory tillage in a DSR system could vary depending on the dominant weeds in the system, vertical seed distribution and the weed seed dynamics. A study was conducted to test the efficacy of ZT and CONT and their interaction with herbicide treatments on the weed population dynamics and rice grain yield in 2010 and 2011. Tillage systems did not affect weed emergence, weed biomass, tiller production and crop yield. However, herbicide treatments varied in their efficacy on individual weeds. Hand-weeding treatments and pendimethalin combined with hand weeding did not effectively control Cyperus rotundus L. and Panicum maximum Jacq. (a perennial grass weed with underground parts). The herbicide combination of metsulfuron and chlorimuron was effective in controlling C. rotundus but not grass weeds. This indicates the need for sequential applications of herbicides for grass weed control or integration of hand weeding to achieve broad-spectrum weed control. Apart from hand weeding (three times), treatment with penoxsulam–cyhalofop and pendimethalin followed by (fb) hand weeding resulted in low weed density, high tiller production and grain yield. The study clearly indicates that tillage does not always lead to weed suppression compared with ZT, and herbicides must be chosen based on the dominant weeds in a system. The results of this study are pertinent as herbicide-resistant weeds are rapidly evolving under continuous herbicide selection pressure, which warrants studies on enhancing productivity through low-input, environmentally friendly and sustainable production technology.     

绥化市大豆田主要杂草发生及防除对策研究

采用路线踏查与定点观察相结合方法对绥化市大豆田主要杂草种类及发生规律进行调查,并在此基础上对杂草的防除技术进行研究,结果显示:绥化市大豆田杂草共有15科24种,并且杂草发生期集中,高峰期的出草量占总出草量的85%左右.化学防除技术研究显示土壤封闭、茎叶处理所用不同除草剂单混效果不同.并对化学除草的注意事项进行说明,应根据气候条件、土壤墒情、大豆发育进度、杂草大小等灵活运用防除对策.     

Weed control in conservation agriculture systems of Zimbabwe: Identifying economical best strategies

Weed management under conservation agriculture (CA), especially when manually controlled is one of the major setbacks for the widespread adoption of CA in southern Africa. This study was conducted at three on-station and three on-farm sites: CIMMYT-Harare, Domboshawa Training Centre and Henderson Research Station (on-station sites), Hereford farm, Madziva communal area and Shamva communal area (on-farm sites). The evaluation focused on the effect of initial herbicide application and succeeding manual weeding whenever weeds were 10 cm tall or 10 cm in length for grasses with stoloniferous–rhizomatous growth habit. Weeds counts, weeding time and grain yields were collected at all on-station sites. At the on-farm sites, weed counts were done before weeding and a number of farmers were timed during weeding. The results showed that herbicides use reduced the weed density and time taken on weeding at all sites. Combining herbicides e.g. atrazine, glyphosate and metalachlor had the lowest weed density and weeding time at all sites. However, the treatments had no effect on maize grain yields suggesting that appropriate and timely manual weeding reduced crop/weed competition. Herbicides treatments had higher input costs than manual weeding due to the additional cost of herbicide but the treatment with manual weeding only had more overall labour days compared to the mixture of three herbicides. In order to achieve economic benefits, smallholder farmers may use the time for value addition e.g. expand cropped land area, use time for value addition, or sell new products on the market. Herbicides use reduces the manual labour needed to control weeds and minimise total crop failure due to untimely weeding hence, herbicides are an important but not the only weed control option under CA systems in Zimbabwe.     

阔草清（Flumetsulam）防除大豆田杂草的研究

阔草清（Ｆｌｕｍｅｔｓｕｌａｍ）是美国陶氏益农公司新近研制的一种磺酰受类除草剂。经３年试验证实，该除草剂用一大豆田，进行播后苗前土壤处理，可防除多种阔叶草杂，对大豆安全。该除草剂可与乙草胺或杜耳混用，兼治禾本草与阔叶草。适宜用药量为单用８０％阔草清５６－７５ｇ／ｈａ，混用上述剂量加５０％乙草胺２．５－３Ｌｈａ，或加７２％杜耳２Ｌ／ｈａ。