河北省谷子田常见杂草种类及发生规律与化学防除

采用随机区组试验方法,进行谷田杂草常见种类调查,并对其中主要发生种类的发生规律进行了研究.结果表明,河北省谷田常见杂草38种,分属15个科,发生基数较大的杂革有20种.春播谷田以双子叶杂草为主,占杂草总数的60.08％,夏播谷田以单子叶杂草为主,占杂草总数的64.38％.春播谷田杂草发生有3个蜂期,分别为5月中旬,6月下旬,7月上、中旬.夏播谷田杂草发生仅1个峰期,一般为7月上、中旬;其化学防除以44％单嘧·扑灭WP1 800 g/hm2为最经济、有效使用剂量,可有效防控整个谷子生长期的杂草.     

浅水藕田杂草发生特点及控制技术

1浅水藕田杂草的发生特点 1．1杂草发生时间长,具有明显的萌发高峰期 两年观察结果表明,浅水藕田杂草萌发有一个高峰期,高峰期出现的时间为栽种后10—20d,高峰期间的出草量占总草量的60．3％～69．5％。从各类杂草的萌发数量看,禾本科杂草和莎草科杂草主要集中在栽种后10～15d,其出草量分别占总草量的80．3％和76．8％,呈单峰型发生。阔叶草萌发表现为明显的双峰型,第一峰为浅水藕栽种后15～20d,出草量占总草量的51．9％,第二峰在栽种后30—35d,出草量占总草量的36．5％。     

海门市油菜田杂草发生特点与防除技术

江苏省海门市移栽油菜田杂草多数年份以猪殃殃为优势种,约占杂草发生总量的50%左右,其次为婆婆纳和卷耳,约占杂草发生总量的20%左右.棉花和大豆茬油菜田杂草重于花生和甘薯茬.移栽油菜田杂草防除,首先做好清洁田园,将前茬作物残枝落叶及草籽等带出田外.油菜移栽前用异丙草胺·异恶草松进行土壤封闭.油菜移栽后根据杂草种类及油菜类型选用草除灵、吡氟禾草灵等除草剂防除.     

新疆兵团机采棉田杂草种类及群落结构调查

为明确新疆生产建设兵团机采棉田杂草发生情况,采用倒置"W"九点取样法,对兵团北疆第六师、第十二师及东疆第十三师共11个团场、99块样地、891个样方的杂草进行调查与分析。结果表明,北疆及东疆棉田杂草主要有20科44属46种,其中禾本科杂草7种,占15.2%,阔叶杂草38种,占82.6%,莎草科杂草1种,占2.2%;一年生杂草28种,占60.9%,多年生杂草18种,占39.1%。总体看,龙葵、藜、田旋花、反枝苋为机采棉田优势杂草,野西瓜苗为区域性优势杂草,芦苇、狗尾草、猪毛菜等12种杂草为常见杂草,苦豆子、扁秆荆三棱、苦苣菜等29种杂草为一般杂草。不同区域、不同生育时期机采棉田杂草发生种类及群落结构各不相同,研究结果为机采棉田杂草的综合治理提供了详实的基础数据和科学依据。     

4种除草剂对黄芩田间杂草的防除效果

为筛选出适用于防除黄芩田杂草的除草剂,进行黄芩田施药试验,调查土壤处理除草剂二甲戊灵、氟乐灵播前土壤喷雾、播后苗前土壤喷雾的除草效果,以及茎叶处理除草剂精喹禾灵、高效氟吡甲禾灵对茎叶喷雾的除草效果。结果表明,二甲戊灵和氟乐灵于播后苗前处理土壤后对黄芩田杂草的防效最高,在黄芩出苗后第50天,上述两处理对杂草的鲜质量防效分别为93.99%和94.30%,株防效分别为77.89%和73.33%;二甲戊灵和氟乐灵于播前处理土壤的防效次之;精喹禾灵和高效氟吡甲禾灵处理茎叶的防效最低。     

棉隆土壤消毒联合种植密度防除油菜田杂草及对作物产量和田间光照的影响

在农田杂草的治理中,结合农艺措施来治理草害的发生,可有效减少化学除草剂的使用,实现草害的综合治理。本文采用田间试验研究了棉隆土壤消毒联合油菜不同种植密度对油菜田主要杂草野燕麦Avena fatua、苦苣菜Sonchus oleraceus的防除效果,及杂草对氮、磷、钾及水分消耗的影响。结果表明,土壤消毒联合种植密度对油菜田杂草防除效果显著,对野燕麦、苦苣菜均有良好防效,总鲜重防效达到89.8%～100.0%。采取防除措施后,杂草对田间氮、磷、钾和水分的消耗量减少85%以上,有效改善了田间的水肥和光照条件。土壤消毒联合种植密度不同处理的油菜籽产量达到3 155.0～4 920.5 kg/hm2,增产效果显著,产量较未消毒土壤区增加13.3%～76.8%,增收1 857.3～10 684.8元/hm2。研究表明采用土壤消毒结合种植密度对油菜田杂草具有很好的控制效果,适度增加油菜种植密度既能保证对杂草防效,同时也能保证产量。     

芦笋采笋田杂草发生规律及化除试验

我县是济南市芦笋主要生产基地。采笋田整个采笋期长达3个月(4月10日左右～7月20日前后),停止采笋后芦笋进入生长阶段。一年中,杂草有两个发生期:一是采笋期;二是生长期。近年来,随着芦笋田的大面积承包和生长年限的增加,致使笋田杂草的发生逐年加重,成为芦笋生产面临的重要问题,急需研究应用化学除草技术。为此,笔者从1989年以来,进行了害草调查和化学除草试验,现将结果总结如下。     

仲丁灵对辣椒的安全性及除草生物活性

探讨仲丁灵土壤喷雾处理防除移栽辣椒田杂草的可行性,采用室内盆栽法及田间小区试验测定仲丁灵对反枝苋等杂草的除草效果及对辣椒的安全性。结果表明,仲丁灵防除辣椒田杂草的选择性系数为4.27,安全性好;田间小区试验表明,仲丁灵对反枝苋等辣椒田具有代表性的杂草有很好的防效,施药后40 d的株数防效为84.67%~93.68%,鲜质量防效为88.70%~96.36%;辣椒收获时测产结果表明,除草、增产效果明显。总体可见,仲丁灵对于辣椒田具有代表性的杂草具有防效高、杀草谱广、安全性好等作用特点。     

地膜马铃薯田的杂草发生与防除

1998～1999年进行了地膜马铃薯田杂草发生与防治研究 ,结果表明 ,地膜马铃薯田杂草有10科17种 ,主要优势种为猪殃殃、婆婆纳、看麦娘。播后约20d田间有一个明显的出草高峰。杂草防除每667m²用33%施田补200ml、48%氟乐灵100ml喷雾 ,防效达90%以上。     

湖北省秋收旱地作物田化学除草技术介绍

我省秋收旱地作物田杂草在农作物苗期以禾本科及莎草科杂草发生为害为主,在作物中后期则以阔叶杂草发生为害为主。本文分土壤处理剂和茎叶处理剂两个方面具体阐述了我省秋收作物田杂草化学防除技术。     

The effect of sowing date, stale seedbed, row width and mechanical weed control on weeds and yields of organic winter wheat

Three field experiments were carried out in organically grown winter wheat in Denmark. The treatments were sowing time (normal or late sowing) and false seedbed, row width (12 and 24 cm) and weed control method [untreated; mechanical weed control (weed harrowing at 12 cm supplemented with inter‐row hoeing at 24 cm); and herbicide weed control]. Weed biomass in midsummer was greatest on plots sown at the normal sowing time (compared with delayed sowing) and was reduced by mechanical or chemical weed control (compared with untreated plots). Row width alone had no influence on weed biomass, but in the experiment with high weed pressure, the more intensive mechanical weed control used at a row width of 24 cm reduced weed biomass. Normal sowing time tended to give higher yields, but this was only statistically significant in one of the three experiments. Wide rows gave a yield decrease in the experiment with low weed pressure. The effect of weed control on yield was dependent on the weed pressure. At low weed pressure, mechanical weed control caused a yield decrease compared with untreated or herbicide treated. At intermediate weed levels there were no differences, whereas at high weed pressure, mechanical weed control and herbicide treatment caused a yield increase compared with untreated. False seedbeds were shown to contribute to a decrease in the soil seed reserve.     

三种苗前除草剂对茅苍术杂草防治效果及安全性评价

为了筛选出防效好、残留少且对环境影响较小的茅苍术苗前除草剂,选取常用的3种苗前除草剂乙草胺、乙氧氟草醚和二甲戊灵,研究其除草效果,对叶绿素荧光参数的影响,农药残留情况及其对土壤微生物真菌和细菌群落的影响。结果表明,乙草胺的除草效果较好,株防效和鲜重防效都达到了80%以上,对茅苍术叶绿素荧光参数影响较小,农残较少,对土壤细菌和真菌群落无显著性影响;乙氧氟草醚和二甲戊灵对叶绿素荧光参数有影响,短时间内有一定的土壤农残。综合防效和安全性,优选乙草胺作为茅苍术的苗前除草剂。     

Simulating evolution of glyphosate resistance in Lolium rigidum II: past, present and future glyphosate use in Australian cropping

Glyphosate is a key component of weed control strategies in Australia and worldwide. Despite widespread and frequent use, evolved resistance to glyphosate is rare. A herbicide resistance model, parameterized for Lolium rigidum has been used to perform a number of simulations to compare predicted rates of evolution of glyphosate resistance under past, present and projected future use strategies. In a 30‐year wheat, lupin, wheat, oilseed rape crop rotation with minimum tillage (100% shallow depth soil disturbance at sowing) and annual use of glyphosate pre‐sowing, L. rigidum control was sustainable with no predicted glyphosate resistance. When the crop establishment system was changed to annual no‐tillage (15% soil disturbance at sowing), glyphosate resistance was predicted in 90% of populations, with resistance becoming apparent after between 10 and 18 years when sowing was delayed. Resistance was predicted in 20% of populations after 25–30 years with early sowing. Risks of glyphosate resistance could be reduced by rotating between no‐tillage and minimum‐tillage establishment systems, or by rotating between glyphosate and paraquat for pre‐sowing weed control. The double knockdown strategy (sequential full rate applications of glyphosate and paraquat) reduced risks of glyphosate and paraquat resistance to <2%. Introduction of glyphosate‐resistant oilseed rape significantly increased predicted risks of glyphosate resistance in no‐tillage systems even when the double knockdown was practised. These increased risks could be offset by high crop sowing rates and weed seed collection at harvest. When no selective herbicides were available in wheat crops, the introduction of glyphosate‐resistant oilseed rape necessitated a return to a minimum‐tillage crop establishment system.     

Reduction in field emergence and seedbank density of Galinsoga quadriradiata and other weeds after contrasting false seedbed strategies in organic vegetable fields

Mechanical weed control in low competitive, organic vegetable production systems is challenging, particularly in fields with large populations of Galinsoga spp. (Asteraceae). Various false seedbed techniques are used prior to crop planting or sowing to prevent weed emergence, albeit with variable success. This study investigated the impact of machinery type (flamer, hoe and harrow), number of passes (2 and 4), tillage depth (1–4 cm) and intensity (double and single hoeing, and hoeing with or without additional harrowing) on weed emergence and seedbank density in 0–5 cm topsoil of organic vegetable fields. False seedbed machinery that did not or minimally disturb the soil was most appropriate for preventive control of Galinsoga quadriradiata (Hairy galinsoga) and total weed seeds, with reductions in seedling emergence up to 99% and 73%, respectively, for flaming, and 74% and 67%, respectively, for 1 cm deep hoeing, 1 month after false seedbed creation. Compared with 1 cm deep hoeing, 1 cm deep harrowing was 16% less effective in the control of emerged seedlings, while flaming was highly effective in preventing weed seedling emergence, even after a low number of passes. Tillage intensity was less important than tillage depth for the reduction in weed emergence and seedbank density. Overall, tillage was more effective for seedbank reduction than flaming.     

60．8％异丙甲·乙氧·扑草净EC防除花生田杂草的效果

采用田间试验测定了60．8％异丙甲·乙氧·扑草净乳油（ EC）在花生田的除草效果及其对花生的安全性。结果表明：用该药剂在花生播后苗前进行土壤处理,对马唐、鸭跖草、马齿苋、藜等具有很好的效果,推荐使用剂量1368～1824 g/hm2,药后45 d的杂草株防效为81．73％～83．69％,鲜质量防效为81．77％～84．93％。此外发现,该药剂对花生具有较高的安全性,处理区花生未见叶片黄化、畸形或苗株矮化等药害症状。与空白对照相比,施用60．8％异丙甲·乙氧·扑草净EC后增产显著,同时增产效果优于对照药剂乙草胺,说明60．8％异丙甲·乙氧·扑草净EC对花生安全,且除草、增产效果显著。     

Best timing for glyphosate treatments and possible combinations with pre and post-emergence weed control practices in no-till maize

Use of reduced and no-tillage systems has increased in recent years due to concerns for ecological and economic sustainability of agricultural production. Effective weed control is a serious concern in reduced tillage production. This study was conducted to investigate weed control practices in reduced and no-till maize production. The most effective timing of glyphosate application, either before or after sowing, was investigated in combination with pre-emergence application of acetochlor (840 g a.i/L), post-emergence application of foramsulfuron (22.5 g a.i/L), and two hoeing treatments. The treatments were maintained on the same plots during 2011 and 2012 to evaluate the cumulative effects of the treatments. Main plot treatments consisted of four timings of glyphosate application: 20 or 10 days before sowing, day of sowing, 5 days after sowing, and an untreated control. Sub-plot treatments were: pre- plus post-emergence herbicides, pre-emergence herbicide plus rotary hoeing, post-emergence herbicide plus rotary hoeing, and post-emergence herbicide plus two hoeing treatments (rotary and lister hoe). In the main plots, the lowest weed biomass was produced in glyphosate treatments at sowing and 5 days after sowing; the highest biomass was produced in control plots and in the plots with glyphosate treatments 20 days before sowing. In the sub-plots, the greatest weed biomass was produced in plots with two hoeing treatments (rotary and lister hoe). Glyphosate treatments at sowing and post-emergence herbicide treatment combinations produced the best weed control. Economic analysis revealed that pre-sowing, non-selective herbicide treatments provided a slight increase in net profit. Mechanical hoeing decreased net income due to increased production costs. The highest income was obtained from the pre-emergence plus post-emergence herbicide treatment combinations with no glyphosate.     

CONTROL OF WEEDS IN MARROWSTEM KALE BY EPTC AND SOME OTHER HERBICIDES

Summary. Two experiments on chemical weed control in marrowstem kale are reported. In the first of these three herbicides applied before sowing were compared; in the second experiment four herbicides were studied, one applied before sowing and the others applied after emergence. Of all the herbicides examined, EPTC, applied before sowing and incorporated into the seedbed, was the most satisfactory in terms of both weed control and yield of kale. Neither endothal + propham nor dinoseb + TCA proved satisfactory as pre-sowing treatments. The three herbicides applied post-emergence (all methylmercapto triazines) were ineffective for the control of Polygonum spp. and Poa annua , although fairly effective against Stellaria media and Chenopodium album . They caused considerable damage to the crop and reduced yields by at least 25%.
Le désherbage du chou moellier par l'EPTC et quelques autres herbicides     

Predicting the risk of weed infestation in winter oilseed rape crops

Chemical weed control before crop and weed emergence is a systematic practice in winter oilseed rape crops in France. It would be profitable both for farmers and the environment to predict the level of weed infestation early on in the growing season and to control weeds only when necessary using post‐emergence weed control. The objective of this paper was to develop and evaluate simple models to predict weed biomass in oilseed rape crops. The model input variables were related to weed population characteristics and farmers’ practices. The models can be used to classify oilseed rape plots into two categories: plots with a level of weed infestation above a threshold or those with level of weed infestation below a threshold. A data set including 3 years of experiments, conducted across several regions in France, was used to estimate the parameters and to evaluate the models. High values of sensitivity and specificity were obtained when weed biomass was predicted as a function of sowing date, type of soil tillage, soil mineral nitrogen, crop density, weed density at emergence, and main characteristics of the most abundant weed species. Model performance strongly decreased when input variables related to the weed population were not taken into account. The best models correctly classified 90% of the plots with high weed infestation and 64% of the plots with low weed infestation.     

Secondary dispersal, spatial dynamics and effects of herbicides on reproductive capacity of a recently introduced population of Bromus sterilis in an arable field

An arable field was subdivided and subjected to either deep inversion ploughing or non‐inversion cultivation after viable seeds of Bromus sterilis had been sown into oilseed rape stubble. After sowing in isolated plots distributed within the field, sequences of cropping treatments for the establishment of two successive winter wheat crops were applied. Each subfield was split into an uphill and a downhill direction for soil cultivation. The field had a 10° slope. In the season following seed introduction, 2.6% of the introduced seeds had successfully germinated and established in the non‐inversion cultivation regime, when no effective graminicide was applied. Ploughing eradicated B. sterilis. Using differential global positioning system (DGPS) mapping of the whole field population, emerged plants were observed up to 8.7 m (uphill treatment) and 21.3 m (downhill treatment) of their initial source. The median distance seeds were transported was 2.3 m uphill and 4.8 m downhill. Post‐emergence application of the herbicide propoxycarbazone slightly reduced weed density and seed weight, and almost halved weed seed production. Application of fenoxaprop‐P‐ethyl was followed by higher density of plants, tillers and seeds of B. sterilis. Seed viability was unaffected by herbicide use. Thus, in the second wheat crop following seed rain, the weed population was dispersed more widely in the field, such that 20–30% of seeds were dispersed more than 5 m distance from the first year's foci of infestation. The relevance of soil cultivation to secondary dispersal of B. sterilis is discussed.