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...     

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。     

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。     

50%滴丁·异丙草乳油防除玉米田杂草效果研究

50%滴丁.异丙草乳油于2006年防除玉米田杂草结果表明,在2062.5 g(a.i.)/hm2剂量以上时对一年生禾本科杂草和阔叶类杂草具有较好的防除效果,株数防效在82%以上;鲜重防效达85%以上。在试验剂量范围内该药剂对玉米产量没有影响。     

硝磺草酮与二氯吡啶酸复配应用于玉米田除草效果测定

采用室内生物测定方法,研究硝磺草酮与二氯吡啶酸复配联合作用类型,对复配制剂进行田间效果试验。结果表明,硝磺草酮对马唐、稗草效果较好,对马齿苋、铁苋菜效果差;二氯吡啶酸对马齿苋、铁苋菜效果较好,对马唐、稗草近无效。两者复配后优势互补,作用类型均为相加作用。硝磺草酮与二氯吡啶酸两者混配剂可作为备选药剂进行田间试验,茎叶处理防除玉米田杂草,推荐比例为0.67~2.67∶1。田间试验结果表明,硝磺草酮与二氯吡啶酸复配后综合两种单剂优势,对试验田杂草马唐、马齿苋、铁苋菜和苘麻均有很好效果。     

甲磺草胺除草活性及对甘蔗的安全性研究

为明确甲磺草胺在蔗田的应用前景,采用温室盆栽法土壤处理对其杀草谱、除草活性及其对甘蔗的安全性进行了测定。结果表明:甲磺草胺对蔗田常见的禾本科、莎草科杂草和阔叶杂草有较好活性,当处理剂量为有效成分70 g/hm2时,对光头稗(Echinochloacolonum)、牛筋草(Eleusineindica)、马唐(Digitariasanguinalis)、香附子(Cyperusrotundus)、绿苋(Amaranthusviridis)和龙葵(Solanumnigrum)的鲜重抑制率均高于90%,对筒轴茅(Rottboellia cochinchinensis)、铜锤草(Oxalis corymbosa)和鹅绒藤(Cynanchum chinense)的鲜重抑制率高于80%;甲磺草胺对光头稗、牛筋草、马唐和香附子等4种主要蔗田杂草的除草活性均显著高于敌草隆;甲磺草胺在甘蔗品种‘新台糖22号’与光头稗、牛筋草、马唐和香附子之间的选择性系数依次为2.04、2.67、2.95和2.25,均明显高于对照药剂敌草隆的1.74、1.68、1.80和1.24;在甘蔗品种‘桂糖46号’与杂草间的选择性系数与‘新台糖22号’相近。研究结果表明甲磺草胺对蔗田多种主要杂草防效较好,且对广西种植面积最大的两种甘蔗品种安全,因此可以作为蔗田苗前除草剂的备选药剂。     

高山茶园杂草发生规律与防治对策

高山茶园大多位于600m以上,新垦茶园以狗牙根、辣蓼为主,幼龄茶园春季主要是菵草、一年蓬、荠菜、小飞蓬、猪殃殃;秋季主要是马唐、牛筋草、虮子草、小旱稗、一年蓬、碎米莎草、铁苋菜、马齿苋等。投产茶园主要是马唐、狗尾草、蟋蟀草等大量滋生。春季一年蓬、菵草、猪殃殃、婆婆纳、繁缕、簇生卷耳为主;秋季马唐、牛筋草、一年蓬、小旱稗、铁苋菜、小飞蓬、爵床等为主;其中发生最为普遍和为害最严重的种类有马唐、狗尾草、狗牙根、辣蓼、白茅等几种,在比较潮湿的地段,则以香附子、酢桨草等为主;衰老茶园中一些瓜蒌、海金砂等攀缠性杂草数量增多。根据其生长和危害季节差异,可分为春季和夏秋杂草两大类,防治对策:农业和化学防除,在每年3次杂草旺发前进行防治,注意化学除草的方式和方法,提高防除效果。     

30%烟嘧磺隆·莠去津·硝磺草酮可分散油悬浮剂对甜玉米田杂草的防效及安全性

研究30%烟嘧磺隆·莠去津·硝磺草酮可分散油悬浮剂在甜玉米田的应用效果,在甜玉米不同叶龄期开展田间试验,评价其对杂草的防除效果及对甜玉米的安全性。结果表明,30%烟嘧磺隆·莠去津·硝磺草酮可分散油悬浮剂在甜玉米3～4叶期或6～7叶期施药,900～1 575 g a.i./hm2剂量范围内对甜玉米品种粤甜28安全,对玉米田常见杂草凹头苋、光头稗、马唐和香附子的防效及增产效果均显著高于对照药剂38%莠去津悬浮剂2 160 g a.i./hm2播后苗前处理。推荐30%烟嘧磺隆·莠去津·硝磺草酮可分散油悬浮剂在900～1 350 g a.i./hm2范围内,甜玉米3～5叶期茎叶喷雾使用。     

15%磺草酮水剂防除玉米田杂草田间使用技术研究

15%磺草酮水剂于2008年进行的茎叶处理防除玉米田杂草试验表明,在800 g a.i./hm2以上剂量处理对玉米田禾本科和阔叶类杂草的综合防效分别高于80%和84%,对玉米安全.     

二甲戊灵微囊悬浮剂室内除草活性及花生田间效果研究

本文利用室内活性测定和田间药效试验相结合的方法,研究450g/L二甲戊灵微囊悬浮剂对花生田杂草的防除效果。结果表明,450g/L二甲戊灵微囊悬浮剂室内对反枝苋和稗草均有较好的活性,ED90分别为345.23g a.i./hm2、465.03g a.i./hm2,对反枝苋的活性高于稗草。田间试验结果表明,450g/L二甲戊灵微囊悬浮剂作为土壤封闭处理剂对花生安全性好,持效期长,环境效益好,对一年生禾本科杂草、牛筋草、阔叶杂草马齿苋和反枝苋均有较好的防效,田间推荐用量为742.5~1012.5g a.i./hm2。     

不同氮肥施用量对东北玉米田杂草发生的影响

利用吉林省梨树县黑土区氮肥长期定位试验田(施氮水平为0、60、120、180、240、300 kg/hm2),2019～2020两年调查玉米田杂草种类、密度和生物量及其与玉米生物量和产量的关系.结果表明,试验条件下玉米田杂草主要是禾本科杂草,尤其是水稗草Echinochloa oryzoides.与不施肥相比,60 k...     

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。     

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%。     

Weed control and sweet maize (Zea mays L.) yield as affected by pyroxasulfone dose

Pyroxasulfone is a new herbicide being considered for registration in sweet maize in Canada; however, there is still little information on the doses required to provide 90% control of annual grass and broadleaved weeds found in southwestern Ontario. The objective of this study was to determine pyroxasulfone doses that would provide at least 90% control of several economically important weeds, without impacting final sweet maize yield by more than 5% in comparison to a weed-free control. Six field trials were conducted over a two-year period (2007 and 2008) at three Ontario locations to evaluate the effectiveness of pyroxasulfone at doses ranging from 31.25 to 1000 g a.i. ha⁻¹. The doses required to reduce weed biomass by at least 90% (I₉₀) varied by weed species. Doses of 93, 499, and 111 g a.i. ha⁻¹ were required to reduce the biomass by 90% of redroot pigweed, common lambsquarters and green foxtail, respectively. There was greater than 95% control of velvetleaf, large crabgrass and barnyardgrass with 31.25 g a.i. ha⁻¹, the lowest dose tested. Sweet maize yield could not be consistently maintained within 5% of the weed-free control. There are several factors that may have contributed to the reduced yield, including soil texture effects, competition as a result of poor common lambsquarters control, and hybrid sensitivity. These results show that biologically effective weed control with pyroxasulfone may be achieved at lower than proposed doses for several weed species; it remains unclear if this is economically sustainable due to the potential impacts on yield.     

Allelopathic effects of Ambrosia artemisiifolia L. in the invasive process

Ambrosia artemisiifolia (common ragweed), an annual native to North America, is now present in many European countries where it causes summer hay fever and interferes with several important crops. We investigated if common ragweed invasiveness could be explained by its leaf tissue and root exudate allelopathic potential on indicator crops (alfalfa, barley, maize, lettuce, tomato, and wheat), weeds (Echinochloa crus-galli, Solanum nigrum, Portulaca oleracea, and Digitaria sanguinalis), and common ragweed itself in laboratory and greenhouse conditions. Different residue substrates were prepared for soil incorporation and trials were conducted under both laboratory (1, 2, and 3 g residues/Parker dish) and greenhouse conditions (1.28 g residues/pot). The effect of the preparations on the germination and growth of the indicator crops and weeds were evaluated relative to soil previously used to grow A. artemisiifolia. Results showed tomato was the most sensitive indicator crop species as growth was reduced by more than 50% in both laboratory and greenhouse experiments. Lettuce root and shoot growth were also inhibited, but only when common ragweed residues, and not root exudates, were added to the substrate. Among the weeds, E. crus-galli was not affected by common ragweed while D. sanguinalis suffered a large germination reduction (90%) after incorporation of 3 g of residues. If common ragweed occurred as weed in a field, the cultivation of a less sensitive crop such as winter wheat should be considered before the cultivation of a more susceptible crop.     

间作豆类作物对玉米田中杂草防控作用的研究

采用玉米/豆科植物间作技术,通过在玉米行间撒播和条播豆类植物,研究玉米/豆科植物间作对抑制杂草生长的作用,防治玉米田杂草危害。结果表明,豆科植物通过与杂草的空间竞争,对玉米田中经常发生的杂草马唐、牛筋草、反枝苋、马齿苋等具有明显的控制效果,并对玉米有一定的增产作用。综合比较,绿豆撒播的种植方式对杂草的防控效果和对玉米的增产作用最好。     

Glyphosate management strategies,weed diversity and soybean yield in Argentina

From their introduction in 1996, glyphosate resistant (GR) soybean cultivars have been rapidly adopted by farmers in Argentina and in other countries in the world. The high rate of adoption of this technology seems to be based on the simplicity of use provided by a single herbicide (glyphosate), its high efficacy to control many weeds and, the low costs of the technology relative to that used in conventional crops. During 2001–2002, 2002–2003 and 2003–2004 soybean growing seasons, field surveys and field experiments were performed with the aim of studying the effect of different glyphosate management strategies on the diversity of soybean weed communities, weed control, individual survival, fecundity and crop yield. In addition, the emergence pattern of three important weeds, Digitaria sanguinalis, Cyperus rotundus and Anoda cristata, was also studied. Both field surveys and field experiments were carried out on no-till soybean crops sown immediately after wheat or barley harvest (double cropped system). Experiments were set up in commercial soybean crops and consisted of different times of a single glyphosate application, two glyphosate applications and also the application of glyphosate plus a residual herbicide imazethapyr. A. cristata, D. sanguinalis, Stellaria media, Chenopodium album and Cyperus sp. were the most prevalent weeds recorded at pre-harvest of the soybean crops, showing regional constancy higher than 80% in both years. In three out of four field experiments, crop yield was not increased when glyphosate was applied twice compared with a single application of the herbicide. In addition there was a lower negative effect on weed species richness when glyphosate was applied once during the crop cycle than with two applications of glyphosate or glyphosate plus imazethapyr. D. sanguinalis escaped the glyphosate early treatment because of the long weed emergence period, while A. cristata and C. rotundus survived treatments due to their high individual tolerance. The results suggest that it is possible to manage glyphosate application to get high crop yield with a low impact on weed diversity, depending on the weed species and their abundance.