Two-Year Weed Seedling Population Responses to a Post-Emergent Method of Site-Specific Weed Management

Field experiments were conducted to determine how a site-specific weed management practice in Zea mays L. influenced the numerical and spatial distribution of a naturally occurring weed infestation in Z. mays and the succeeding Beta vulgaris L. crop. Compared to conventional broadcast herbicide applications, site-specific herbicide applications reduced herbicide load by 11.5 and 98.0% in two separate Z. mays fields. The broad range in outcomes was attributed to the spatial aggregation and density of target weed populations. While herbicide use was successfully reduced at field locations with low weed density, most survivors of multiple control tactics were in locations with the highest initial density. A greater understanding of interactions between weed management and weed density would increase the likelihood that site-specific weed management offers long-term improvements over conventional approaches.     

Evaluation of Site-Specific Weed Management Implementing the Herbicide Application Decision Support System (HADSS)

A major concern of producers has always been how to reduce the amount of inputs required for crop production while maintaining or improving yields. One area of research addressing this issue is site-specific weed management (SSWM). The objective of this research was to evaluate the possibility of using SSWM herbicide applications to reduce overall production costs when site-specific weed populations are known. Weed populations of three soybean fields (B-East, B-South, B-North), located at the Black Belt Branch Experiment Station, Brooksville, MS, were estimated in 1998 and 1999. Sampling occurred July 8–9, 1998 (8 weeks after planting), and June 30–July 1, 1999 (6 WAP). An established 10 m × 10 m Universal Transmercator (UTM) grid coordinate system was used to divide the fields into 100 m² cells, with the sample point located in the center of each cell. Optimal herbicide recommendations were obtained for each sample location within each field by subjecting the weed information to the Herbicide Application Decision Support System (HADSS). An average of the weed populations for the entire field was also subjected to HADSS to obtain an optimal recommendation for a broadcast application for comparison purposes. Data from 1998 resulted in 25% and 15% of the field not requiring a herbicide treatment for the B-North and B-South when compared to the whole-field recommendations to receive broadcast treatments. However, B-East received a no treatment recommendation for the whole-field analysis. The no treatment recommendation was attributed to the sicklepod population exceeding a level deemed economically controllable by HADSS. However, when SSWM recommendations were generated, 49% of the field received no treatment recommendation, while 51% resulted in a herbicide application as an economical choice. In 1999, glyphosate-resistant transgenic soybean was used, thereby increasing the POST herbicide treatment options available in HADSS. Herbicide treatment recommendations resulted in 100%, 56%, and 91% of the total area requiring herbicide treatments for B-East, B-North, and B-South, respectively. Comparing the projected net returns for each field can develop a better estimate of the value of SSWM. In 1998, data from the B-East resulted in a projected net return increase of $21.63 ha^–1 over that of the broadcast application. Estimated net return increased $5.42 ha^–1 at B-North, with simulated SSWM applications over broadcast applications, and $14.67 ha^–1 increase at B-South. Net returns for 1999 resulted in only a $0.32 ha^–1 increase by using SSWM for B-East, but a $21.00 and $13.56 ha^–1 increase for B-North and B-South, respectively. The extra expenses of SSWM, such as sampling and technology costs, are not included in the net returns calculations and, when included, would reduce the difference between SSWM and conventional methods. This research has demonstrated the potential value of SSWM from an economic standpoint; environmental benefits through reductions in herbicide applications are also apparent.     

快灭灵防除小麦,玉米及水稻田杂草试验

快灭灵是一种新型茎叶处理除草剂,每公顷用有效成分30g喷雾,可有效防除小麦、玉米和水稻田的多种阔叶杂草,如荞麦蔓、藜、凤花菜、苘麻、狼巴草和眼子菜等,平均防效在80％以上。快灭灵对供试作物均有一定的接触性药害,典型症状为叶片上形成枯斑,但不影响作物最终产量．     

Crop/Weed Outcomes from Site-Specific and Uniform Soil-Applied Herbicide Applications

While uniform broadcast application (BC) of soil-applied herbicides is the norm, advances in geospatial technologies have enabled the deployment of site-specific herbicide application (SS). Since there are several, largely-untested decision rules for SS herbicide use, the objective of this work was to evaluate crop/weed outcomes and isoxaflutole use for a number of BC and SS strategies. Field experiments were established where isoxaflutole dose response functions were quantified from early-season Zea mays (L.), Sorghum bicolor (L.) Moench., and Abutilon theophrasti Medic. response data at multiple plots (64 in 1999; 62 in 2000) throughout a variable field. These data were then used to infer crop and weed outcomes from simulated application strategies. While BC and SS strategies that relied on the product label were similar in terms of total herbicide use, extent of crop tolerance, and A. theophrasti efficacy, the SS strategy resulted in a significant redistribution of herbicide. Using biologically effective doses (ED) resulted in the highest efficacy and herbicide use was highly species-dependent. By using a historical weed map of the field to guide herbicide application, herbicide use could be reduced some 20–48% when following the product label where seedlings were present, or >90% when using the ED for A. theophrasti. In order to maximize the potential agronomic benefits of SS, biological and spatial information of both the weed and soil should be taken into account.An erratum to this article can be found at     

天津地区麦田杂草发生现状与防除对策

通过对天津地区麦田杂草发生现状的调查 ,阐述麦田杂草的危害及优势杂草产生变化的原因 ;结合麦田除草剂应用情况及杂草防除试验 ,探讨以药剂防除为主的防除对策。     

Site-Specific Herbicide Decision Model to Maximize Profit in Winter Wheat

A user-friendly computerized agricultural herbicide decision model has been developed for selecting profitable site-specific herbicide applications in winter wheat. The model is based on 6 years of field research in southeastern Washington State, USA. The model calibrates herbicide applications to management unit weed densities, soil organic matter, soil moisture, and preceding management, as well as to expected input and output prices. The model increased broadleaf herbicide rates by an average 0.65 of label rates compared to the recommendations by farmers and weed science professionals, but cut the more expensive grass herbicides by an average 0.56 of label rates. The model increased average projected profitability, excluding model application costs, by 65% compared to four other criteria for determining application rates. The profitability increase relative to local farmers was 19%. Both the model and the cooperating farmers properly chose to use no grass herbicides on the study sites, but the weed science experts chose to use up to 1.0 of label rates. The estimated payoff from using the model substantially exceeded the cost of weed scouting and other information collection. Determining economically optimal sampling and management units is an important challenge for the adoption of precision agriculture models like the one developed in this study.     

Soil and Weed Survey for Spatially Variable Herbicide Application on Railways

Weed control on railways is frequently done by herbicide application, using large amounts of chemicals and labour. Only a few hectares of surface area on a railway can be many kilometres long so high levels of spatial variability of soils and weeds are expected. Railway sprayers use similar technology to crop sprayers so it is possible to adopt concepts from precision agriculture for weed control. The objective of this study was to evaluate spatial variability of soils and weeds on railways in order to define weed control strategies and basic characteristics of a railway sprayer. This work is part of a research project aiming at the development of a system for spatially variable herbicide application on railways. Soil and weed data were collected from five different railway companies in Brazil. These data were used to simulate treatment maps based on weed control strategies and to estimate technical requirements for spatially variable herbicide application. The results showed that soil and weed survey gave important information for defining weed control strategies and spraying equipment. The sprayer must treat the three swaths (left, central and right parts of the railway surface) separately applying at least two different herbicides at the same time. On average, a variable dose rate application based on the treatment maps generated in this work could save up to 59% of herbicides.     

40%乙·扑乳油防除玉米田杂草试验

通过田间小区及大区对比试验的结果表明,40%乙草胺(Acetochlor) 扑草净(Prometryne)EC,对玉米田多种杂草,如稗草、马唐、狗尾草、鸭跖草、藜、铁苋菜等均有特效,防除效果稳定在90%以上。在杂草基数低于200株·m-2的地块,用药量为3000mL·hm-2,超过200株·m-2的地块,用药量为3750~4500mL·hm-2,施药时期为播种后5~9d。该除草剂对玉米安全、无药害,且不影响下茬作物生长。     

天津麦田杂草化学防除现状和问题

介绍了天津麦田杂草发生与危害的现状,总结了麦田杂草化学防除的特点及除草剂的应用现状,并针对其存在的问题提出相应建议,以期对麦田化学除草技术的推广及避免麦田化学除草中出现的问题有所帮助。     

春草秋治对麦田杂草的防治效果

在河北省曲周县选择6个村庄的麦田进行春草秋治效果试验,不同村庄的小麦主栽品种不完全相同。采用对比试验设计,2013年11月中旬（小麦播种后1个月）利用自走式机械喷药机用苯磺隆150～180 g/hm^2对水450 kg/hm^2喷雾施药,以不进行任何处理的麦田作为对照。2014年3月对麦田杂草的发生种类和数量进行了调查。结果表明：播娘蒿为该地区麦田的主要杂草;春草秋治可以有效降低示范方杂草的发生种类、田间频率和田间密度,降低播娘蒿的相对密度,个别地块甚至出现杂草灭绝的效果。春草秋治技术具有较好的应用效果和推广前景。     

江苏省小麦田间杂草的生态经济防治阈期

通过多点试验 ,建立小麦田苗后有草天数或无草天数与小麦产量损失率之间的函数关系 ,探明江苏省小麦田间杂草的生态经济防治阈期。结果表明 :江苏省小麦田间杂草的生态经济防治阈期约为小麦出苗后 17～ 87d ,相当于小麦全生育期的 9 5 %～ 48 3% ,此时小麦处于 3叶期至 7～ 8叶期 ,此阈期的始期和终期 ,为田间杂草密度及生物量的快速增长期。在此阈期内保持田间无草 ,既能保证杂草造成的减产率低于 3 % ,又能充分发挥杂草在田间生态系统中所起的积极作用     

3种除草剂对大麦田杂草防除效果及产量效应

通过田间药效试验,比较6.9%大膘马、5.8%双氟磺草胺和5%唑啉草酯3种除草剂及其混剂对大麦田杂草的防效以及对大麦的安全性和增产效果。结果表明:6.9%大膘马单剂(禾本科杂草)、5%唑啉草酯1 800 m L/hm~2(禾本科杂草)和5.8%双氟磺草胺150 m L/hm~2(阔叶类杂草)对相应大麦田杂草都有较好的防控作用,鲜重防效率达到91.3%以上,而5%唑啉草酯1 200 m L/hm~2和5.8%双氟磺草胺120 m L/hm~2防效一般,鲜重防效率分别为86.90%和87.1%;6.9%大膘马与5.8%双氟磺草胺混配两类杂草防除效果显著,但对大麦产生3级药害,5%唑啉草酯和5.8%双氟磺草胺混配药效持久,对大麦安全,杂草的鲜重防效率达到92.97%以上,且增产率分别达到9.91%和11.9%。     

50%苯磺隆·异丙隆可湿性粉剂在冬小麦田的除草效果研究

采用田间试验方法研究了50%苯磺隆·异丙隆可湿性粉剂在冬小麦田的除草效果。结果表明: 冬前1次用药, 对麦田的雀麦、播娘蒿、荠菜和麦瓶草等双子叶杂草有较好防效。适宜用药时期为10月20日~11月10日, 推荐剂量为1 875~2 250g/hm2。     

皖北地区夏玉米病虫草害综合防控技术研究

针对皖北地区玉米生育期常发的病虫草害,从玉米拌种、播种到收获整个生育期着手,选用新型药剂,优化植保技术在玉米生长期的应用策略,最大限度地减少玉米病虫草害造成的损失。结果表明,在全生育期应用植保技术的示范田比常规防治田、空白对照田的苗情好,病虫草害明显减轻,产量增幅明显。     

新疆麦田杂草种类、分布危害及其综合防治技术

系统调查表明,新疆麦田杂草约有107种,隶属于24个科,常见种46种,主要分布于6个科,以播娘蒿、灰黎、艹扁蓄、田旋花、野燕麦、稗草和狗尾草等为优势种群。麦田杂草群落演替呈现播娘蒿、田旋花等恶性杂草比重上升,传播和蔓延较快,发生呈明显加重趋势的特点。盆地、河谷区域和平原区麦田杂草总体上以双子叶杂草为主;高海拔山地麦区以单子叶杂草为主;山地与海拔相对低的绿洲平原之间的过渡麦区,单、双子叶杂草危害程度基本相同。一般春麦区杂草危害重于冬麦区。采取以化学除草为主,农业措施为辅的综合防除技术可有效控制麦田草害发生与危害。     

小麦全生育期病虫草害综合防控试验示范研究

[目的]探讨适合陕西省三原县大面积推广的小麦全生育期病虫综合防治技术。[方法]在三原县开展了小麦全生育期病虫草害综合防控试验示范。[结果]组合药剂拌种处理能使小麦苗齐、苗壮,较对照农艺性状优良;进行全生育期综合防控的麦田,即实施组合药剂拌种、春季及时喷施除草剂进行麦田除草、抽穗-灌浆期的不同时期开展小麦病虫"一喷三防",均有显著的病虫防效和增产率;以小麦抽穗率达60%~70%时实施第1次,隔7 d后实施第2次"一喷三防"的防虫、防病、增产效果更显著。[结论]试验结果为三原县小麦生产提供了参考。     

江苏省长江以北地区麦田杂草群落的定量分析

用 7级目测法调查江苏省长江以北地区 6 9个样点的 6 38块麦田共计约 5 4 5hm2 的草害情况 ,数据转化成综合值后 ,进行主成分分析 ,并赋予生态学意义上的解释。研究结果表明 ,决定江苏长江以北地区麦田杂草发生、分布和危害的主要因素是土壤水分、土壤性质 地带性气候因素 ;主成分分析结果表明 ,生境相似 ,杂草群落有趋同性 ;可将 6 9个样点划分为 3个聚类群 ,即沿海旱茬麦类群、内陆旱茬麦类群和稻茬麦类群 ,各聚类群均有相应的优势杂草 ,粘毛卷耳、波斯婆婆纳、刺儿菜、猪殃殃等为沿海旱茬麦田优势杂草 ,内陆旱茬麦田的主要杂草是播娘蒿和麦家公 ,稻茬麦田的杂草优势种为硬草、棒头草 ,并就该地区杂草发生的特点提出了综合治理的建议     

硬茬复播玉米和大豆田主要杂草及化学防除技术研究

硬茬复播田杂草种类达15科27种。采用除草剂JNH－1,JNH－2或JNH－3进行苗前土壤处理,对已出苗和未出苗的杂草皆有极显著防效,一次用药不仅可保证作物苗期免遭草害,而且对作物生育后期的杂草也可达到有效控制。所用除草剂均对玉米、大豆安全。由于有效减轻了草害和虫害,大豆平均增产19．4％,玉米平均增产26．2％。     

伊犁河谷平原冬麦田杂草调查及防除技术

运用倒置"W"9点取样法对伊宁市冬麦田杂草调查表明:伊犁河谷平原冬小麦田杂草有29种,隶属16个科。其中菊科和十字花科各6种,豆科、紫草科和禾本科各2种,旋花科、茜草科、桑科、石竹科、玄参科、藜科、车前科、唇形花科、锦葵科、伞形花科、蓼科各1种,其中灰藜、三叶草、黄花蒿、米瓦罐和狗尾草5种杂草的相对多度分别是40.48%、32.98%、26.48%、26.01%和23.28%,为优势种群。根据其杂草分布特点,采取农业、物理机械防治及化学防治措施,能有效控制草害发生与危害。     

40%异丙草胺·莠去津悬乳剂防除夏玉米田1年生杂草田间药效与安全性监测试验

田间试验结果表明,夏玉米播后苗前使用40%异丙草胺.莠去津悬乳剂125～350g/667m2,对夏玉米田阔叶杂草和禾本科杂草均有较好的效果,有较长的持效性和安全性。