影响黄河流域常规除草棉田机械采收的恶性杂草调查

为明确黄河流域棉区影响棉花机械采收的恶性杂草发生情况,于2013―2014年对河北、山东、天津共6个地点前、中期采取过不同除草措施的棉田杂草进行了调查。结果表明,播前使用过二甲戊灵的覆膜棉田,5月底行间(不包括膜下)有阔叶类杂草10科16种,占杂草总株数的96%左右;有禾本科杂草5种。2014年所有杂草的田间密度自5月底至6月底增长较快,之后部分阔叶类杂草和禾本科杂草缓慢增长,8月底以后保持稳定;另一部分阔叶类杂草6月底后即不再增长,至8月底或9月中旬后快速下降;7月底揭膜后杂草密度不再明显增加。前期和中期采取过除草措施的棉田,后期发生数量大、对机采影响也较大的普遍恶性杂草包括绕藤类的裂叶牵牛和亚灌木状的龙葵、苘麻、藜和反枝苋,区域性恶性杂草有攀援类的广布野豌豆和亚灌木状的苍耳。     

沿海农区麦田杂草防除技术研究

根据沿海农区麦田杂草发生危害现状，麦田杂草可分为禾本科和阔叶类2大类，进行了硬草(禾本科恶性杂草之一)、泽漆(新上升难治阔叶类杂草)的发生危害规律和有关生物学特性的基础研究，重点研究了控制麦田硬草、泽漆的关键措施，明确了应用化学除草剂(骠马、乙草胺、异丙隆、使它隆、苯磺隆及其复配剂)的核心所在，结合其它有关专题研究结果，在先进的原则策略指导下，组装了沿海农区麦田杂草长效治理技术措施。     

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。     

沿海农区麦田杂草防除技术研究

根据沿海农区麦田杂草发生危害现状 ,麦田杂草可分为禾本科和阔叶类 2大类 ,进行了硬草 (禾本科恶性杂草之一 )、泽漆 (新上升难治阔叶类杂草 )的发生危害规律和有关生物学特性的基础研究 ,重点研究了控制麦田硬草、泽漆的关键措施 ,明确了应用化学除草剂 (骠马、乙草胺、异丙隆、使它隆、苯磺隆及其复配剂 )的核心所在 ,结合其它有关专题研究结果 ,在先进的原则策略指导下 ,组装了沿海农区麦田杂草长效治理技术措施。     

盘锦稻区水田杂草种类及优势度情况

采用随机调查方法,于2016年至2018年对盘锦稻区水田杂草种类进行调查,共调查17科共36种杂草,其中稗草、稻稗、扁秆藨草、藨草、水绵、野慈姑等10种杂草为盘锦稻区主要杂草种类,发生总量占杂草总量的88.77%。禾本科、莎草科、阔叶类杂草及水绵仍是盘锦稻区近三年来造成水稻产量损失的草害性杂草。     

瑞飞特防除水田杂草试验

为确定瑞飞特对水田杂草的防治效果，在田间采用大区对比法进行药效试验。试验结果表明，瑞飞特50％EC 1050ml／hm^2 超畏30％WP 150g／hm^2，在水稻移栽田一次性施用，可有效防除禾本科及阔叶杂草，对水稻安全，无药害发生。     

大麻高效除草（封闭）技术研究

本文利用不同除草剂进行播后苗前（封闭）处理,对大麻生产期田间杂草综合防治效果进行了研究。研究结果表明：采用65％异丙甲草胺乳油3L／hm2封闭除草,对禾本科杂草防效可达55．6％。对阔叶杂草龙葵、藜、蓼、苋的防治效果分别达到66．7％、37．5％、88．9％、89．5％,对阔叶杂草蓼、苋防治效果比较理想：采用40％施田扑乳油3L／hm2封闭除草,对禾本科杂草防效可达63．9％,对阔叶杂草龙葵、藜、蓼、苋的防治效果分别达到75．0％、75．0％、66．7％、57．9％,阅叶杂草龙葵、藜比较理想。两种除草剂对禾本科杂草均较好的抑制生长效果。     

棉田阔叶杂草发生危害与化除应用

1棉田主要阔叶类杂草及危害 棉田由于长期应用防除禾本科杂草的除草剂，导致阔叶类杂草的发生危害日趋严重，表现为种类多，分布广，生长力旺，单株覆盖面积大，与棉株大量争夺水分、养料、空间，致使棉株生长势弱，结铃数少而且小，直接影响棉花的产量和品质。阔叶类杂草的优势种在主要棉区之间有较大差别。     

除草剂混配施用对棉田常见杂草的防除效果

为了检验除草剂防除棉田杂草效果,以三氟啶磺隆、嘧草硫醚和精喹禾灵之间不同剂量的混配施用.试验表明：三氟啶磺隆和精喹禾灵两种混用及三氟啶磺隆、嘧草硫醚和精喹禾灵3种混用均对棉田杂草都有较好的防除效果.施药后7天杂草表现药害症状.施药后20天,三氟啶磺隆与精喹禾灵两种除草剂混用,随着三氟啶磺隆用量的增加对禾本科杂草的防效由89.2％增加到95.3％,对阔叶类杂草的防效由86.3％增加到94.9％,总体株防效由87.8％增加到95.2％;三氟啶磺隆与精喹禾灵、嘧草硫醚混剂3种除草剂混用,在精喹禾灵用量相同的条件下,增加三氟啶磺隆或嘧草硫醚的用量,对禾本科杂草、阔叶类杂草、杂草总体株防效均提高.施药后40天的株防效和鲜重防效均80％以上,说明混配药剂的持效期较长.     

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％.     

苏北垦区豆田杂草生长为害习性

苏北垦区豆田杂草分属15科,36属,41种,恶性杂草有稗,苍耳等9种。在大豆整个生育期间通常出现1～2个萌发高峰,主要集中在6月中旬～7月下旬。杂草种子于8～10月成熟。种子在土壤中的埋深及出苗期,直接影响杂草的出苗和繁殖。杂草与大豆的相互竞争,以在大豆播种一个月后最为剧烈。0～2cm和6～25cm耕层中贮葳的杂草种子最多。     

辽宁省春玉米田杂草的生态经济防治阈期研究

在沈阳、庄河两地的田间试验,建立了玉米田苗后有草天数或无草天数与产量损失率间的函数关系模型,明确了辽宁省春玉米田杂草的生态经济防治阈期为玉米出苗后18～65 d.在此期间内保持田间杂草少于经济防治阈值,既可确保杂草造成的减产率低于3%,又能充分发挥杂草在生态系统中的积极作用.     

长沙地区茶园杂草调查及防除关键措施

长沙地区各类茶园,春末、夏初的主要杂草是马唐、狗尾草、野塘蒿、扛板归、野艾蒿、狗牙根、革命草.为害程度:幼龄茶园>台刈茶园>成龄茶园.多年牛杂草占50%以上,提出防除多年生杂草滋生蔓延的关键措施.     

湿润直播稻田杂草出苗动态与发生规律

 1996～1997年在浙江嘉兴调查了湿润直播稻田杂草出苗动态和发生规律,并比较了直播与移栽,早稻、单季晚稻与连作晚稻直播,翻耕与免耕直播间杂草发生差异。湿润直播稻田杂草以稗草、千金子、异型莎草、节节菜、陌上菜为主,其次有通泉草、丁香蓼、水芹。禾本科、莎草科和阔叶杂草种类数分别占25.0%、18.8%和56.2%,出苗数量分别占11.2%、11.6%和77.2%。单季晚稻直播田稗草、千金子发生重于其他直播田,直播田稗草和千金子数量明显高于移栽田。直播田杂草于播种后3～4 d陆续出苗,1～3周达到高峰。连作晚稻直播田播后6～8周出现明显的第二个出苗高峰。以阔叶杂草为绝对优势的翻耕直播田杂草发生重于免耕田。直播田杂草数量自然消长呈现与出苗动态相同的趋势。直播田杂草发生以稗草、千金子、丁香蓼较早,节节菜、陌上菜、通泉草次之,异型莎草和水芹较迟。稗草、千金子及其他几种主要杂草出苗高峰均呈单峰状态,而节节菜、陌上菜在连作晚稻直播田的出苗则为双峰。     

White clover selected for enhanced competitive ability widens the compatibility with grasses and favours the optimization of legume content and forage yield in mown clover‐grass mixtures

White clover‐grass mixtures should provide swards with a high dry matter (DM) yield with a clover proportion of at least 0·30. This study assessed the compatibility of one white clover variety selected for competitive ability (Giga) and four other large‐leaved clover varieties (Aran, Espanso, Fantastico and Regal) in mown binary mixtures with each of four grass companions (cocksfoot cv. Padania, hybrid ryegrass cv. AberExcel, Italian ryegrass cv. Crema, and tall fescue cv. Magno) over 3 years in northern Italy. On average, the mixtures including Giga had at least a two‐fold greater clover proportion in the total harvested DM (P < 0·01) and contained fewer weeds (P < 0·10) than those with other clover varieties, and also tended to have the highest total DM yields. On average, mixtures containing AberExcel had clover proportions of >0·25 but gave the lowest total DM yields, whereas those of Magno maximized total DM and had a higher proportion of clover than Padania or Crema. No clover × grass interaction was detected (P > 0·05). The association with Giga allowed the tall fescue‐based mixture to attain a clover proportion 0·331 along with a top‐yielding total DM. This mixture, compared with the only one without Giga that displayed a near‐sufficient clover proportion (Espanso with AberExcel), exhibited a 21·7% higher total DM (P < 0·05) and had far fewer weeds.     

云南山地香蕉园主要杂草生态位

运用Levins和Shannon-Wiener生态位宽度以及Pianka生态位重叠指数,研究河口山地蕉园主要杂草的生态位动态,分析其香蕉园内优势杂草生态位对旱季、雨季的动态响应特征,为云南山地蕉园杂草生态防控提供指导依据。结果表明：雨季和旱季的杂草在生态位宽度和重叠上均有着显著的变化。雨季的马唐（Digitaria sanguinalis）、光头稗（Echinochloa colona）、香附子（Cyperus rotundus）的生态位宽度最大,旱季的白花鬼针草（Bidens pilosa）、小飞蓬（Conyza canadensis）、鹅肠菜（Myosoton aquaticum）的生态位宽度最大;雨季和旱季杂草间的生态位重叠普遍较大,分别占66.7%和 44.4%,相似性比例较高,重叠值均大于0.50,其均值分别为0.54和0.40。以上结果表明,河口山地香蕉园杂草无明显的单优势种,杂草间对资源的利用存在较高的竞争或互补。其生态位宽度和重叠值较大的杂草会随着群落演替的延续,在资源配置不足的情况下加剧竞争而排挤掉其他杂草。     

冬季亚麻杂草种类危害及防除研究

本文调查研究了州内亚麻种植地区的田块杂草种类、分布和发生规律。查清杂草共有101种，隶属25科，发生危害重的有7科26种，占25．74％；双子叶杂草77种，占76．23％，单子叶杂草22种，占21．78％，蕨类杂草2种，占1．98％。一年生杂草42种，占42．58％，越年或一年生杂草29种，占28．7l％，多年生杂草30种，占29．7l％。杂草随亚麻的播种而生长，至枞形期达最高峰，88—1231株／m^2。防治上在亚麻枞形期（株高5—10cm）、杂草2—3叶期选择50％敌草隆＋5％精喹禾灵或50％敌草隆＋56％二甲四氯钠盐，兑水喷雾，防除效果达90％以上。     

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.     

云南红河流域热带作物园区杂草组成及群落特征分析

采用相对优势度、物种丰富度指数、Shannon-Wiener指数、Simpson指数、Pielou指数、群落相似性指数等生态学指标及聚类分析的方法,对4种作物地杂草进行分析。结果表明：该地区农田杂草共有116种,隶属于37个科,其中禾本科和菊科种数较多,分别占总数的21.55%和19.83%;鬼针草（Bidens pilosa）和牛筋草（Eleusine indica）在各作物园区普遍为害,为常年优势恶性杂草,应重点防控;各作物地杂草的多样性,橡胶地最高,其次为香蕉地,菠萝地和油梨地多样性较低;多样性指数的季相变化规律,4种作物地均表现为夏秋季高于冬春季;杂草群落相似性和聚类分析结果一致表明：菠萝蜜地与油梨地杂草群落相似度最高,其次为香蕉地与菠萝蜜地,再次为香蕉地与油梨地,橡胶地与其他3种作物地相似度均较低。     

Contribution of white clover varieties to total sward production under typical farm management

White clover varieties, potentially suitable for inclusion in seed mixtures for mixed stock-rearing farm systems, were evaluated when growing with S23 perennial ryegrass under rotational sheep grazing with a silage cut in late May or early June, as practiced on farms. Monoculture grass swards were also included to enable the direct and indirect contribution of white clover to total sward production to be evaluated.
White clover increased total sward production during all three years of the trial by an average of 50%. Although clover content of swards were similar, large differences occurred in their grass content, especially in the third year, when difference in total yields of swards based on large–leaved clover varieties was 2 t ha ⁻¹ while difference in clover yield was only 0-6 to ha^–1 The indirect contribution of white clover, namely the extra grass resulting from N transfer, was greater in the spring than in the autumn. It was also greater for Nesta than for other varieties. and exceptional for this variety in that the increase in grass yield above that of grass monoculture was maintained over three harvest years.