冀东地区春玉米田杂草群落特征及烟嘧·莠去津配比优选

采用倒置“W”取样法对唐山、秦皇岛主要春玉米产区的田间杂草进行调查，利用茎叶处理法对烟嘧磺隆+莠去津药剂组合进行最佳配比筛选。结果表明，冀东地区发生优势度较大的杂草有马唐、稗草、鸭跖草、虎尾草、藜、反枝苋、马齿苋、苘麻、苣荬菜、铁苋菜、小马泡、豚草、葎草、狗尾草共14种。秦皇岛地区以藜、反枝苋、马齿苋、马唐、稗、苘麻、鸭跖草、苣荬菜和虎尾草为主，Shannon''s指数H''为0.63，Shannon''s均匀度指数E为0.09，Margalef物种丰富度指数D_MG为0.98；唐山地区以藜、马唐、鸭跖草、反枝苋、铁苋菜、苘麻、小马泡、豚草、葎草为主，Shannon''s指数H''为0.51，Shannon''s均匀度指数E为0.11，Margalef物种丰富度指数D_MG为1.56。药剂筛选结果显示，与其他处理相比，烟嘧磺隆+莠去津(30 g/hm²+285 g/hm²)组合对玉米田主要杂草的防效最高，药后14 d的株防效为93.55%，药后28 d的株防效和鲜重防效分别为95.32%和93.24%。     

玉米丰产增效技术模式生产效率评价——基于吉林省半湿润区中北部试验数据

采用DEA方法中投入导向的BCC模型，利用吉林省半湿润区中北部2019年底试验和示范的实测数据对玉米丰产增效技术模式进行了生产效率分析。结果表明，2个模式及对照共10个组合的综合技术效率均值达到了0.947，比较接近于1，表明各组合生产效率总体较高，其中规模效率的均值（0.965）略低于纯技术效率的均值（0.991），可见技术水平较为适中，而生产规模有改进的空间。共有4个组合的生产效率最佳，分别是优化密植与耕层调控技术模式在德惠同太的组合3（翻耕+秸秆全量深翻还田+密度7.5万株/hm²+喷药除草）和组合4（翻耕+秸秆全量深翻还田+密度7.5万株/hm²+除草+化控）、优化密植与平衡施肥技术模式在扶余永平的组合7（翻耕+密度7.5万株/hm²+氮肥后移+除草+化控）以及在德惠同太的农户对照组合10（翻耕+秸秆移除离田+密度6.0万株/hm²+一炮轰施肥+喷药除草）。推荐这4个组合在当地今后的生产实际中进行推广。     

异噁唑草酮·噻酮磺隆在玉米不同种植区应用的除草效果和安全性研究

2016～2017年在东北春玉米种植区和黄淮海夏玉米种植区设立田间试验基地,研究除草剂异噁唑草酮·噻酮磺隆悬浮剂在不同区域玉米田播后苗前处理的杀草谱及除草效果、对玉米安全性及对下茬作物生长的影响。结果表明,26.7%异噁唑草酮·噻酮磺隆悬浮剂141.75～283.5 g ai/hm2在玉米播后苗前使用,对东北春玉米种植区主要杂草稗草、狗尾草、藜、反枝苋、苘麻、刺儿菜和黄淮海玉米种植区主要杂草马唐、牛筋草、反枝苋、马齿苋、铁苋菜等禾本科杂草和阔叶杂草均有理想效果,药后40～45 d,异噁唑草酮·噻酮磺隆上述处理对杂草鲜重防效仍在95%左右,可实现一次施药控制玉米全生长期的杂草,在玉米田具有较好的除草增产作用;对后茬播种的小麦、大豆、花生、油菜、菠菜生长无影响。     

三氯吡氧乙酸对小麦的安全性及生物活性评价

三氯吡氧乙酸属人工合成激素类除草剂,具有用量少、活性高、选择性强等优势。为明确其在小麦田的应用技术,采用整株水平生物法测定了其对10个安徽主栽小麦品种的安全性及对阔叶杂草的生物活性。结果显示,三氯吡氧乙酸对多种阔叶杂草具有较好的活性,在供试剂量288 g(a.i.)·hm^-2时,对荠菜、球序卷耳、大巢菜、宝盖草、葎草、猪殃殃、鳢肠、鬼针草、野老鹳、播娘蒿、牛繁缕、小飞蓬、羊蹄、车前草、青葙活性较好,鲜重抑制率达90.39%~100%;在用量72 g(a.i.)·hm^-2时,对葎草鲜重抑制率达100%,对播娘蒿、荠菜、牛繁缕、球序卷耳、大巢菜、小飞蓬、羊蹄、猪殃殃的活性次之,鲜重抑制率在60.44%~84.30%之间;其对阿拉伯婆婆纳、荠菜、播娘蒿、野老鹳的GR₅₀值分别为97.13、43.03、48.58、54.37 g(a.i.)·hm^-2。安全性结果表明,在用量576 g(a.i.)·hm^-2时,对10个供试小麦品种均较安全,株高抑制率和鲜重抑制率分别在2.98%~13.34%和3.29%~17.47%之间。三氯吡氧乙酸在4种供试小麦烟农999、荃麦725、安农0711、淮麦44和杂草阿拉伯婆婆纳、荠菜、播娘蒿、野老鹳草之间的选择性指数在2.39~12.70之间,表明该药剂在供试小麦与杂草间具有良好的选择性。     

4种除草剂对夏玉米田杂草及麦苗的防效与安全性比较

选用4种莠去津复配剂进行玉米田杂草防除效果及安全性研究,筛选对夏玉米田杂草及自生麦苗的防效及安全性较好的除草剂。结果表明,31.5%噻酮磺隆·异噁唑草酮+38%莠去津总杂草株防效为88.7%,鲜质量防效为98.48%,防效较好,无明显药害症状,且玉米产量为各药剂处理中最高;22%烟嘧·莠去津和30%苯唑草酮+助剂+38%莠去津对自生麦苗株防效均在80%以上,鲜质量防效在95%以上;30%苯唑草酮+助剂+38%莠去津对莎草的株防效仅45.58%,莎草为主的夏玉米田块尽量不使用。     

40%异丙草·莠悬乳剂防除春玉米田杂草药效的研究

室内生物活性测定结果表明:由异丙草胺和莠去津复配而成的40%异丙草·莠悬乳剂具有明显的增效作用.田间小区药效试验施用该药4.5～6.0 kg/hm²对玉米田一年生单双子叶杂草防治效果达85%以上,持效期60～70 d,且对作物安全,比人工除草增产9.0%～12.9%。     

灌水和施肥对垄作沟灌啤酒大麦产量及水分利用效率的影响

为给甘肃河西绿洲灌区啤酒大麦垄作沟灌栽培的水肥管理提供参考,通过裂区试验,设置4个不同灌溉定额(1 500 m·hm^-2、2 100 m·hm^-2、2 700 m·hm^-2和3 300 m·hm^-2)和3个不同施肥水平（N 75 kg·hm^-2+P₂O₅56.25 kg·hm^-2、 N 150 kg·hm^-2+P₂O₅112.5 kg·hm^-2、N 225 kg·hm^-2+P₂O₅168.75 kg·hm^-2）,研究了灌水和施肥对垄作沟灌栽培啤酒大麦产量及水分利用效率的影响。结果表明,灌溉定额、施肥量及水肥互作对啤酒大麦的产量和水分利用效率均有明显影响。当灌溉定额从1 500 m·hm^-2增大到2 700 m·hm^-2时,啤酒大麦千粒重提高5.36 g,成穗数增加1.16×10⁶·hm^-2,增产57.99%,水分利用效率提高24.12%;灌水量超过2 700 m·hm^-2时,增产效果不明显。在N 75～150 kg·hm^-2、P₂O₅56.25～112.5 kg·hm^-2范围内,增施肥料有利于啤酒大麦千粒重和穗粒数增加,并显著提高产量和水分利用效率。在灌溉定额2 700 m·hm^-2、纯N 150 kg·hm^-2、P₂O₅ 112.5 kg·hm^-2条件下,垄作沟灌栽培啤酒大麦的产量和水分利用效率分别为6 239.84 kg·hm^-2和13.33 kg·mm^-1·hm^-2,水肥利用效果和经济效益相对较优。     

异噁唑草酮防除玉米田杂草及玉米安全性效果测定

采用室内生物测定和田间效果试验相结合的方法,研究异噁唑草酮在室内及田间对玉米田杂草活性及玉米安全性。室内试验结果表明,异噁唑草酮土壤处理对马唐、稗草、马齿苋和苘麻均有很好的效果且对玉米安全,其中对阔叶杂草马齿苋和苘麻的效果好于禾本科杂草马唐、稗草,对苘麻和马齿苋的GR_(90)值在2.69~6.39 ga.i./hm~2,对马唐和稗草的GR_(90)值在29.32~29.69 ga.i./hm~2。田间试验结果也表明,异噁唑草酮对玉米田杂草马唐、稗草、牛筋草、反枝苋、狗尾草均有很好的效果且对玉米安全。     

吉林省不同类型土壤玉米施肥效应研究

吉林省东、中、西不同类型土壤田间试验结果表明:不同类型土壤的氮、磷、钾肥施用模式符合二次曲线Y=ax²+bx+c。利用该模式,结合肥料和玉米价格进行综合分析,明确了不同类型土壤上的氮、磷、钾施用效益,即东部冲积土玉米最佳施肥量为N192kg/hm²、P2O556kg/hm²、K₂O33kg/hm²;中部黑土玉米最佳施肥量为N133kg/hm²、P₂O₅38kg/hm²、K₂O47kg/hm²;西部淡黑钙土玉米最佳施肥量为N59kg/hm²、P₂O₅65kg/hm²、K₂O51kg/hm²。     

夏玉米应用普利复合生物肥增产效果的初步探讨

本试验结果证明，夏玉米基施或苗期追施普利复合生物肥450～1500kg/hm²，均有增加穗粒数、提高千粒重，达极显著增产的作用。其中以基施或追施1500kg/hm²效果最好，分别增加穗粒数147粒、99粒；千粒重提高21g、18g；增产34.2%和33.8%。并比基施或追施975kg/hm²、450kg/hm²的处理，增产达极显著水平。     

How long can a herbicide remain in the spray tank without losing efficacy?

Five field trials were conducted over a three-year period (2006–2008) at two locations in southwestern Ontario to determine the length of time herbicides can remain in the spray tank prior to application in the field without impacting efficacy. Four pre-emergence and five post-emergence herbicides were mixed at their labelled rates and then applied in maize. Herbicides were either applied immediately after mixing in water, or after being held in solution for 1, 3 or 7 days. The most common weed species in the trials were Abutilon theophrasti, Amaranthus retroflexus, Ambrosia artemisiifolia, and Chenopodium album. Holding the herbicides in spray solution for up to 7 days did not affect the efficacy of the post-emergence herbicides in this study. Similarly, control of A. retroflexus and C. album with the pre-emergence herbicides was not affected holding the herbicides in spray solution for up to 7 days. However, control of A. theophrasti was decreased when isoxaflutole plus atrazine, dimethenamid plus dicamba/atrazine, or rimsulfuron plus S-metolachlor plus dicamba was in spray solution for more than 1 day. Nonetheless, there were no decreases in yield for any of the treatments evaluated. These data provide valuable information which growers can use to make informed decisions on whether to apply herbicides in non-ideal weather or to postpone application. The results of this study suggest that for the herbicides and weed species tested it is better to postpone application rather than make applications under non-ideal conditions.     

Evaluation of combinations of paraquat plus photosystem II-inhibiting herbicides for controlling failed stands of maize (Zea mays)

Existing plants remaining in failed stands of maize must be removed prior to planting a subsequent crop, and glyphosate and glufosinate are generally ineffective because of the presence of herbicide-resistant genes in most US maize. Research was conducted at three locations in 2009 to evaluate maize control with paraquat as influenced by (1) the addition of three PSII-inhibiting herbicides, (2) maize growth stage at application with and without addition of atrazine, and (3) time of day of application with and without addition of atrazine. Delaying an application of paraquat beyond the V4 stage (four visible collars) of maize resulted in ineffective control of maize, and the addition of atrazine to paraquat improved control of older plants. A paraquat dose of at least 525 g/ha was often needed for acceptable control of maize. Of the three PSII-inhibiting herbicides evaluated, maize control was generally greater and more consistent with the addition of metribuzin or diuron to paraquat than with atrazine, even though atrazine did often improve control over paraquat alone. Applying paraquat at sunset did improve control over applications made near sunrise, but a PSII-inhibiting herbicide was still needed with paraquat to maximize control of maize. These findings demonstrate that undesirable maize plants can be effectively controlled with combinations of paraquat plus PSII-inhibiting herbicides when applied no later than the V4 stage of maize, and applications in close proximity to sunset can further improve control.     

东北中西部地区玉米田农药使用现状与分析

2015～2018年对东北中西部春玉米区玉米病虫草害防治用药情况进行调查。结果表明,该区域玉米田化学农药的使用量占农药总使用量的99%以上。吉林省玉米田农药年均用量为3 216.45 g a.i./hm~2,内蒙玉米田化学农药年均用量为1 133.44 g a.i./hm~2。各类化学农药按照使用量排序依次为除草剂杀虫剂杀菌剂,除草剂使用量占农药总用量的75%以上。苗后除草剂用量显著低于苗前除草剂用量,选择苗后除草的农户比例和应用面积逐年增加,各类苗后除草剂存在不同程度的超量应用现象。提出通过以草优化配方,减少长残留除草剂用量、明确苗后施药关键时期、升级施药器械、开展技术培训等措施、结合病虫害绿色防控技术,集成农药减施综合技术模式。     

Response of maize (Zea mays L.) to post-emergence applications of topramezone

Topramezone is a new herbicide for post-emergence control of broadleaf and grass weeds in maize. Two field experiments were conducted in northern Greece in 2008 and 2009 to determine the response of grain maize to topramezone applied with the adjuvant DASH at 2–4, 4–6 and 6–8 maize leaf stage. In both years, plant height, cob number and yield were not differently affected with the use of herbicide at these growth stages, indicating no difference in selectivity and a similar response of maize to the three post-emergence applications of topramezone. Slight injury symptoms of leaf bleaching were observed in the second year, however, they were transient with no lasting injury on maize growth.     

Efficacy of four post-emergence herbicides applied at reduced doses on weeds in summer maize (Zea mays L.) fields in North China Plain

Field experiments were conducted in 2010 and 2011 in a typical location of North China Plain to evaluate weed control efficacy of four post-emergence herbicides nicosulfuron, mesotrione, topramezone and the combination of mesotrione/nicosulfuron when they were applied at reduced doses at different weed growth stages. Experimental results showed that nicosulfuron, topramezone and the combination of mesotrione/nicosulfuron provided better weed control efficacy than mesotrione when they were applied at their label recommended doses at the 2- to 3-leaf and 4- to 5-leaf stages of weeds; nicosulfuron and mesotrione/nicosulfuron could at least be reduced by 33% and topramezone reduced by 67% without sacrificing total weed control efficacy and maize grain yield. Nicosulfuron and its combination with mesotrione could effectively control broadleaved and grass weeds when their doses were reduced by 67% and by 33%, respectively. Topramezone could effectively control broadleaved and grass weeds when its dose was reduced by 67%. The efficacy of mesotrione in controlling grass weeds was bad even at the label recommended dose. All four herbicides tested did not affect the maize grain yield.     

砜吡草唑对玉米田杂草的除草活性及其安全性评价

采用生物测定方法研究新型除草剂砜吡草唑对玉米田主要禾本科杂草马唐、牛筋草、稗草、狗尾草的除草活性,通过安全性测定评价砜吡草唑对玉米等作物的安全性.结果表明,砜吡草唑土壤封闭处理对马唐、稗草、牛筋草、狗尾草均具有良好的生物活性.砜吡草唑处理剂量(有效成分)为120 g/hm2时,对马唐、稗草、牛筋草、狗尾草的鲜重抑制率分...     

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.