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1.
In direct-seeded upland rice (Oryza sativa L.) yield reductions due to weed competition ranged from 42 to 65% in field experiments conducted in eastern Utter Pradash, India. The most critical period, when crop losses due to weed competition were most severe, ranged from 10 to 20 days after emergence. Yields generally continued to increase, however, as the length of the weed-free period increased. The weed flora consisted of various grasses, sedges and broadleaved species. The most effective herbicide treatment evaluated was a pre-emergence application of alachlor followed by a post-emergence application of propanil or one mechanical weeding. 相似文献
2.
A. G. T. BABIKER 《Weed Research》1982,22(2):117-121
Unrestricted weed growth resulted in serious yield losses (60–75%) in rice (Oryza saliva L.). Hand-weeding once at 2 weeks after crop emergence was ineffective, but weeding at 2 and 2 weeks after crop emergence brought yield losses down to 20%. Pre-emergence application of bifenox and oxadiazon (12 l) and post-emergence application of molinate + propanil gave crop yields comparable to that of the clean weeded control (91–129%). Grain yields obtained with pre-emergence application of oxadiazon (25 EC) and post-emergence applications of propanil, bentazone + propanil, and bifenox alone or as a tank mix with propanil or bentazone were considerably less than those obtained from the clean weeded plots. Bifenox, oxadiazon (12 l) and propanil + molinate gave adequate and persistent weed control (72–97%), and did not damage rice. Oxadiazon (25 EC) gave good weed control but resulted in a serious stand reduction. Post-emergence application of propanil, propanil + bentazone bifenox alone or as a tank mix with propanil or bentazone had no adverse effect on crop stand, but gave poor control of grasses (0–40%). 相似文献
3.
Effective weed management in maize-wheat (M-W) cropping systems are accountable for higher yield and plant biomass. The objective of this study was to evaluate the effectiveness of manual weeding and chemicals (pre- and post-emergence herbicide) for actual weed control to enhance maize yield and M?W system productivity. Herbicides were treated as pre-emergence (sole), post-emergence (sole) and its combined application (pre- and post-emergence) for weed eradication and suppression. Sole pre-emergence herbicide (acetyclour?+?atrazine) and sole post-emergence herbicides (nicosulfuron), and its mixed application were used in the experiments. The experiment was comprised on 6 treatments with one weedy check or control plot: W1?=?weedy check, W2?=?acetyclour?+?atrazine, W3?=?atrazine, W4?=?nicosulfuron, W5?=?nicosulfuron?+?atrazine, W6?=?acetyclour?+?atrazine?+?nicosulfuron and W7?=?manual weeding. Main weeds were Cyperus rotundus, Tribulus terrestris, Dactyloctenium aegyptium and Cynodon dactylon. Experiential findings revealed that manual weeding was found most effective in terms of controlling weed and suppression. Among the herbicides application, promising results in terms of weed destruction and suppression were shown by combined application of acetyclour?+?atrazine?+?nicosulfuron which effectively controlled weeds as compared to other treatments. It was concluded that manual weeding drastically reduced weeds frequency and biomass while among the herbicides application acetyclour?+?atrazine and nicosulfuron could be promising for weeds suppression and clamp downing as compared to all other treatments under M?W cropping system.
相似文献4.
AbstractA study was carried out in sandy clay loam textured soil of Mymensingh, Bangladesh to evaluate weed control efficiency of pre-emergence herbicide pyrazosulfuron-ethyl either alone or in sequential application with post-emergence herbicide in transplanted rainy season rice under non-puddled strip-tilled (NPST) field condition and also to examine the residual effect of those herbicides on germination and growth of the subsequently grown wheat crop. Five treatment combinations of pyrazosulfuron-ethyl were tested against one weedy check and one weed-free check. The study revealed that NPST rice field was mostly infested by grass and sedge weeds and herbicide treatments offered a wide range of control (above 50% to 95%) on all types of weeds. Application of pyrazosulfuron-ethyl followed by (fb) orthosulfamuron fb butachlor plus propanil provided the most effective and economic weed control over two years of the study. Moreover, micro-plot bioassay study claimed germination and growth of subsequently grown wheat were not adversely affected by herbicides that were applied in rice. Therefore, application of pyrazosulfuron-ethyl followed by post-emergence herbicide could be effective and economic to control weeds in NPST rice under rice-wheat system, but proper rate and time of application should strictly be followed. 相似文献
5.
稻田草害是机插秧生产中最严重的问题。传统水稻田"一封二杀三补"控草策略策略已经不能适应机插秧的除草要求。本文综合小区试验和大区示范,针对不同栽培条件下的土壤和杂草情况,提出"二封一补"的除草对策。3年试验示范结果表明,土地平整后插秧前使用57%苄·丙·异丙隆可湿性粉剂1 500~1 800 g/hm~2进行第1次封闭处理,插秧后10 d用50%苄·丁·异丙隆可湿性粉剂1 200~1 500 g/hm~2进行第2次封闭,既能有效控制早期杂草为害,保证秧苗安全,又能延长对杂草持续控制作用,提高水稻产量。在2次封闭基础上,针对不平整地块和烤田后抗性杂草发生情况,提出相对应的补治措施。 相似文献
6.
在除草剂使用中存在苗前用量偏低或低 ,整地质量差 ,施药过晚 ,土壤干旱 ;苗后施药期天气干旱 ,高温或喷液量过大 ,施药时期偏晚 ,混用不当 ;喷洒器械及喷洒技术落后等影响了药效 ,苗前除草剂应根据土壤有机质及质地确定用药量。采用混土施药法适期施药 ,苗后应因杂草叶龄确定施药时期。混用除草剂选择比例 ,干旱条件下施药时药液中加植物油喷雾助剂 ,选择合适的喷洒器械 ,使用前应进行调整 相似文献
7.
A LUNDKVIST 《Weed Research》2009,49(4):409-416
To assess the effects of timing and frequency of weed harrowing on weed abundance and crop yield, different pre- and post-emergence weed harrowing sequences were applied to spring cereals and peas in field experiments performed during 2003 and 2004 in Sweden. Post-emergence harrowing was performed at crop growth stages 2–3 and 5–6 true leaves respectively. The best weed control was obtained by a combination of pre- and post-emergence harrowing, but these treatments also caused yield losses of 12–14% in spring cereals, while no yield losses were observed in peas. Pre-emergence weed harrowing treatments alone or combined with weed harrowing shortly after crop emergence proved to be most effective against the early emerging annual weed species Sinapis arvensis and Galeopsis spp. Post-emergence harrowing alone in peas had no effect on S. arvensis . The late emerging annual weed species Chenopodium album and Polygonum lapathifolium were most effectively controlled when pre-emergence weed harrowing was combined with one or two weed harrowing treatments after crop emergence. 相似文献
8.
Dogan Isik Mahmut Dok Emine K. Altop Husrev Mennan Bernard H. Zandstra 《Phytoparasitica》2017,45(4):611-618
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. 相似文献
9.
Summary There is a lack of information on the combined effects of preceding crop, reduced tillage (especially no-tillage) and the time of herbicide application on the development of weed populations and the efficiency of weed control in winter wheat in humid temperate climates. An experiment was conducted with a crop rotation (winter wheat – oilseed rape – winter wheat – maize) on a sandy loam and a loamy silt soil in the Swiss midlands to investigate the impact of different preceding crops and pre- and post-emergence control of weeds in conventional tillage (CT; mouldboard plough), minimum tillage (MT; chisel plough) and no-tillage (NT; no soil disturbance systems). When winter wheat was grown after maize and winter wheat was grown after oilseed rape, the ranking order of weed density in treatments without herbicide application was NT < MT < CT and CT < MT < NT respectively. Analysis of variance and canonical discriminant analysis showed that Epilobium spp., Sonchus arvensis , Myosotis arvensis and volunteer crops were more abundant in NT than in MT and CT. The efficiency of post-emergence weed control was generally better than that of pre-emergence weed control, regardless of tillage intensity. 相似文献
10.
An increasing water crisis as well as shortage of farm labor farmers in many Asian regions is forcing a shift from puddled transplanted rice to direct-seeded rice. The weeds, however, are a major constraint to the production of direct-seeded rice. In this perspective, a field study was carried out to evaluate various pre- and post-emergence herbicides and different possible integrated weed management practices in zero-till direct-seeded rice. Weed infestation decreased the rice yield by near about 75%. Co-culture rice with Sesbania followed by (fb) pendimethalin fb 2,4-D effectively reduced the total weed population (65.1%) and biomass (86.7%) at 30 days after sowing (DAS). The lowest total weed dry biomass at 60 DAS was recorded from bispyribac-sodium+azimsulfuron-treated plot and such tank mix application of herbicide performed better against diverse weed flora as compared to a single herbicide. Higher yield and more profit from zero-till direct-seeded rice were obtained with the application of bispyribac-sodium+azimsulfuron herbicides as a tank mixture or an integrated approach through cowpea green-manuring fb 2,4-D+glyphosate fb bispyribac-sodium by effective management of versatile weed flora. 相似文献
11.
Abstract A field experiment was conducted for two years during 1977–78 and 1978–79 to evaluate the efficiency of methabenzthiazuron, terbutryn and metoxuron in controlling weeds in peas (Pisum sativum) at the Punjab Agricultural University, Ludhiana, India. Pre-emergence application of methabenzthiazuron at 1.05 and 1.40 kg a.i./ha gave efficient weed control and gave comparable yields to two hand hoeings. Post-emergence application of methabenzthiazuron proved inferior. Terbutryn pre-emergence showed promise but as a post-emergence application it was ineffective. Metoxuron both pre- and post-emergence showed phytotoxic effects on the crop. 相似文献
12.
Field and pot investigations were conducted to determine the effectiveness of pyroxasulfone alone and its combinations with other herbicides against diverse weed flora of wheat (Triticum aestivum L.) including multiple herbicide-resistant (MHR) littleseed canarygrass (Phalaris minor Retz.). Applications of pyroxasulfone 100–127.5 g/ha as pre-emergence (PE) or early post-emergence (EPOE) @ 63.75 g/ha at 21–23 days after sowing (1 day before irrigation) were highly effective for control of grass weeds namely P. minor and wild oat (Avena ludoviciana Dur.). It was poor for control of broad-leaved weeds (Medicago denticulata Willd. and Rumex dentatus L.). However, pyroxasulfone in tank-mix combination with metsulfuron 4 g/ha, triasulfuron 20 g/ha, and pyroxsulam 18 g/ha effectively controlled (96.5%–99.8%) the diverse weed flora and improved the wheat grain yield (69.5%–285.9%) over untreated weedy control. Also, the pre-mix of pyroxasulfone + pendimethalin applied as PE was superior to either of these applied alone for weed control and grain yield. Pyroxasulfone 100–127.5 g/ha had yield gain of 119.6%–125.4% and 10.1%–26% over untreated control and pendimethalin 800–1250 g/ha, respectively. In pot studies, straw burnt ash drastically reduced the pyroxasulfone efficacy against P. minor and A. ludoviciana. Pyroxasulfone was also effective in pot studies for control of MHR P. minor having resistance against acetyl-coA carboxylase (ACCase), acetolactate synthase (ALS), and photosynthesis at the photosystem-II site-A (PS-II) inhibitor herbicides (clodinafop, sulfosulfuron, and isoproturon, respectively). The studies indicate that pyroxasulfone as PE or EPOE can be an alternative grass weed control herbicide in wheat in particular for the control of MHR P. minor. 相似文献
13.
Reduced fallow length in slash-and-burn rice (Oryza sativa L.) production systems of northern Laos increased weed pressure, labour requirement and the need for soil and moisture conservation. On-farm and on-station studies and on-farm surveys were used to evaluate the effect of residue management and cropping intensity on weed population, rice yield and nematode density. Residue loads were 2.3–4.4 t ha?1 after a rice crop and 9.5 t ha?1 after 1 year of fallow. Compared with farmers' traditional burning of crop and weed residues, mulching reduced rice yield by 43% in one out of four comparisons and increased weed biomass by 19–100%. Compared with continuous rice treatments (averaged over burning and mulching treatments), treatments with fallow or cowpea [Vigna unguiculata (L.) Walp.] in the previous year had 32% less herbaceous weed biomass, 90% fewer Ageratum conyzoides L. and over 99% fewer Meloidogyne graminicola Golden & Birchfield. Rice yield was negatively associated with A. conyzoides density (?0.62, P < 0.01) and M. graminicola number (?0.42, P < 0.05). Less striking effects of fallow period on A. conyzoides and M. graminicola, observed from on-farm surveys, demonstrate the limitations of on-farm studies because of undocumented effects of farmers' management decisions. 相似文献
14.
Using a previous model as a base, data derived in field trials in wheat ( Triticum aestivuort L.) and bailey ( Hordeum vulgare L.) were assessed to estimate the yield penalty, and resulting reduction in economic benefit, from progressive spraying of herbicides up to late crop tillering. Compared with early post-emergence application, yield penalties from delayed spraying began at early tillering. For median values of weed-free yield and weed density in the data set. the loss in potential yield increase when spraying at late tillering compared with early post-emergence was 71%, Crops with higher weed-free yield potential and with greater initial weed density showed a proportionately (as well as absolutely) larger yield penalty from a moderate delay in spraying, indicating an earlier and more intense onset of competition with weeds. 相似文献
15.
In Germany, cultivation of lupines traditionally takes place only in few federal states at sites with light/sandy soil conditions. Due to this fact, there only exist a small number of field trials to close gaps in chemical weed control via herbicides. The existing pre-emergence herbicides are not able to control all of the most common weed species sufficiently-they all show efficiency gaps against single weed species. Not any of the pre-emergence herbicides tested could achieve high efficiencies against Polygonum convolvulus. The best efficiency against P. convolvulus can be achieved after a sequence of a pre-emergence spray of 0,8–1,0 l/ha Fenikan and a post-emergence spray of 0,2 l/ha Tacco. Since Fenikan and Tacco are not approved for lupine, after approval the application only in lupine stocks for seed production is possible. By taking into account only the currently legal permitted herbicides, Gardo Gold and the tank mix Boxer?+?Stomp Aqua show the best broad effects. Benefits resulting from Gardo Gold can be obtained against Chenopodium album, Viola arvensis, Centaurea cyanus, while the tank mixes Boxer?+?Stomp Aqua show advantages against Galium aparine. From the pre-emergence herbicides tested, Successor T could be applied as an addition to improve the broad effect. In tank mixes with Gardo Gold, the most common weed species can be controlled well. However, with permission also this tank mix can currently only be applied in lupine seed stock production. In the near future weed control will only be possible with the currently existing and approved herbicides, because there are no new herbicides to expect that are compatible with corn, grain and lupine. Under suboptimal application conditions of soil herbicides, weeded lupine stocks can only be harvested after siccation. 相似文献
16.
P. N. P. CHOW 《Weed Research》1977,17(1):55-60
Five field experiments were conducted from 1972 to 1975 to evaluate weed control in flax (Linum usitatissimum L.) using post-emergence treatments of asulam [methyl (4-aminobenzenesulphonyl) carbamatel alone and in combination with other herbicides. The 14C-asulam absorption by leaf segments and roots of glasshouse grown wild oats (Avena fatua L.) was also investigated. Asulam at 1.12 kg/ha gave good wild oat control and acceptable control of green foxtail (Setaria viridis (L.) Beauv.). However, wild oat control was poorer when asulam was combined with other herbicides: on a 3-year average, as compared with asulam alone at equal rates, the asulam+MCPA mixture resulted in a greater antagonism and a significant 6% reduction in flax seed yield, whereas the asulam+bromoxynil/MCPA mixture gave the least antagonistic effect, improved broadleaf weed control and increased yield by 13%. In mixtures, the potassium salt of MCPA was more compatible with asulam for weed control than the amine form. Both leaf segments and roots of wild oats absorbed and distributed less 14C-asulam from solutions containing MCPA than from those containing bromoxynil or bromoxynil/MCPA. 相似文献
17.
KRITON K. HATZIOS 《Weed Research》1984,24(4):249-254
In greenhouse studies, the efficacy of the herbicide safeners NA(1,8-naphthalic anhydride), R-25788 (N,N-diallyl-2,2-dichloroacetamide), cyometrinil and CGA-92194 [N-(1,3-dioxolan-2-yl-methoxy)imino-benzeneaceto-nitrile] in protecting grain sorghum (Sorghum bicolor (L.) Moench, cv. ‘Funk G623’) against injury from pre-emergence or early post-emergence applications of the herbicides chlorsulfuron, fluazifop-butyl and sethoxydim was examined. NA as a seed dressing at 0·5 or 1·0% (w/w) was the most effective of the four safeners and offered partial to good protection to sorghum against injury from the lower rates of pre-emergence applications of all three herbicides. R-25788 was totally ineffective as a sorghum protectant against fluazifop-butyl injury but it did antagonize partially the injurious effects of the lower rates of sethoxydim and chlorsulfuron on sorghum. Cyometrinil and CGA-92194 offered partial protection to sorghum against injury from the lowest rate of all herbicides but their efficacy against higher rates of the three herbicides was very limited. None of the four safeners was effective in protecting grain sorghum against injury from post-emergence applications of the three herbicides tested. 相似文献
18.
Dennis Leston 《国际虫害防治杂志》2013,59(3):311-341
Abstract Field experiments were conducted to determine the effectiveness of herbicides in controlling Rottboellia cochinchinensis (Lour.) W. D. Clayton and Cyperus rotundus L. in upland rice (Oryza sativa L.) at different moisture regimes as imposed by a line source sprinkler system. Preemergence application of pendimethalin [N‐(1‐ethylpropyl)‐3,4‐dimethyl‐2,6‐dinitrobenzenamine] was highly effective in controlling R. cochinchinensis irrespective of soil moisture after herbicide application. Bentazon [3‐(1‐methylethyl)‐(1H)‐2,1,3‐benzothiadiazin‐4(3H)‐one 2,2‐dioxide] and 2,4‐D [(2,4‐dichlorophenoxy)acetic acid] applied at postemergence effectively controlled C. rotundus when moisture supply was well above pan evaporation. These herbicides also had no adverse effect on rice stand and resulted in higher yield over the control. Water application rates above upland pan evaporation for a season‐long period was essential to obtain a high response to weed control either by herbicides or hand weeding. The data suggest that proper weed control by herbicides or hand weeding will not result in high upland rice grain yields if moisture level from rains fall below the critical level. 相似文献
19.
I. OKEZIE AKOBUNDU 《Weed Research》1981,21(6):273-278
Several herbicides applied singly and in combination were evaluated for weed control and for their effects on crop yield in direct-seeded lowland rice under poor water management conditions characteristic of the conditions in which lowland rice is grown by most farmers in West Africa. Several herbicides including cyperquat at 3.0 kg/ha, a mixture of cyperquat and 2,4-D at 2.0 + 0.5 kg/ha, bentazon at 2.0 kg/ha and avirosan satisfactorily controlled sedges in the 3-year study. Crop yield was consistently high in plots where weeds were controlled with post-emergence application of MCPA + propanil at 1.0+1.7 kg/ha, propanil + thiobencarb 2.2+1.2 kg/ha, oxadiazon 1.5 kg/ha, bentazon 2.0, granular 2,4-D at 1.0 kg/ha, and a pre-emergence application of bifenox at 2.0 kg/ha. Crop yields in plots treated with these herbicides were generally better than with two hand-weedings. 相似文献
20.
J. W. LUDWIG 《Weed Research》1973,13(1):1-11
Summary. The effectiveness of pre-emergence applications of 2,4-D for weed control in maize was studied In five experiments, in comparison with other herbicide treatments. 2,4-D-aimne applied before crop emergence gave satisfactory weed control if the subsequent conditions were wet, but post-emerge nee applications only killed some species ( Chenopodium album and Atriplex patula. ) A combination of 2,4-D-amine, applied pre-emergence to a moist soil and subsequently as a foliar spray, controlled completely C. album, A. patula, Stellaria media and Veronica spp. Pre-emergence applications of simazine gave better weed control with less need for rain soon after application. Only A. patula was usually resistant. Pre-emergence treatments of atrazine killed all weeds whilst linuron controlled S. media, A. patula., C. album and Sonchus oleraceus but not Veronica spp.
Irrigation experiments showed that weed competition for water was largely responsible for the depressions in the early growth of maize when the conditions were dry. Final yield largely reflected the degrees of weed control attained by the herbicidal treatments. Only 2,4-D applied pre-emergence, and followed by heavy rain caused a direct depression in yield.
Effects des herbicides sur la productivityé du mals fourrage avec référence particuliére aux applications en pré-levée du 2,4-D amine 相似文献
Irrigation experiments showed that weed competition for water was largely responsible for the depressions in the early growth of maize when the conditions were dry. Final yield largely reflected the degrees of weed control attained by the herbicidal treatments. Only 2,4-D applied pre-emergence, and followed by heavy rain caused a direct depression in yield.
Effects des herbicides sur la productivityé du mals fourrage avec référence particuliére aux applications en pré-levée du 2,4-D amine 相似文献