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1.
Summary. Immediate and residual phytotoxicity of binary combinations of several residual soil-applied herbicides at 0·1 and 0·5 ppm was compared to the expected response calculated by Colby's formula. In one experiment diuron was combined with diphenamid, fluometuron, noruron, prometryne or simazine, and in another experiment trifluralin was combined with diuron or dichlobenil. The observed phytotoxicity of most combinations was only slightly different from the expected response. One combination, diuron 0·5 ppm + fluometuron 0·5 ppm, affected mustard significantly more than expected and this synergistic interaction remained appreciable after incubation of 2 months. Interactions entre les herbicides persistants a faible concentration  相似文献   

2.
M. HOROWITZ 《Weed Research》1969,9(4):314-321
Summary. The persistence of ten herbicides in soil was tested in the glasshouse over a 5–month period, using an oat bioassay. Simazine and diuron were highly persistent, atrazine persistent, fluometuron, trifluralin, bromacil and noruron moderately persistent, and pyrazon, prometryne and ametryne of short persistence. Six of these herbicides were also included in a field experiment consisting of logarithmically sprayed strips on which oats were sown at ten intervals of 1 month; changes of herbicidal activity with time were evaluated by measuring the length of the strip showing herbicidal injury. Results corroborate those of the glasshouse experiments except for trifluralin which was more persistent in the field. Disappearance curves were generally sigmoidal. The more persistent compounds showed a long period of slow disappearance followed by rapid disappearance.  相似文献   

3.
Summary. A bioassay was used to study, adsorption of prometryne, simazine, linuron and pyrazon by fibrous peat, sphagnum moss, muck soil and bentonite as 1 % mixtures with quartz sand. Of these bentonite caused least reduction in bioactivity, and sphagnum moss reduced it only slightly more. Fibrous peat and muck soil were the most adsorptive. Prometryne, simazine and pyrazon were more highly adsorbed by fibrous peat than by muck soil, while for linuron the opposite occurred. Fibrous peat was approximately three, seven, thirteen and three times more adsorptive than bentonite for pyrazon, linuron, prometryne and simazine, respectively, while for muck soil the corresponding values were two, fourteen, seven and two. Studies with prometryne and five different soils indicated that percentage organic matter, cation-exchange capacity and specific surface area were all highly correlated with adsorption.  相似文献   

4.
This paper reviews the literature on weeds and weed control in papaya. There is limited research on this topic, and nearly all of the research focuses on herbicides. Effective use of paraquat and glyphosate in papaya is dependent on avoidance of spray contact to green bark and foliage. Pre-emergence herbicide tolerance is dependent on papaya age, size and maturity, and soil type. Only one herbicide, oryzalin is shown to be tolerated by papaya immediately after transplanting. Herbicides such as diuron and oxyfluorfen with a broader spectrum of weed control generally injure young papaya, however they can be effectively used if the initial application of these herbicides is delayed until papaya attains certain size or maturity indices. There is a need for further research on weeds and weed control to improve the efficiency of papaya production  相似文献   

5.
Soil samples taken in summer 1989 and winter 1990 at different depths from three citrus orchards of the Valencia region (Spain) with a long history of residual herbicide treatments were analysed with bioassays and chromatographic procedures. The herbicides involved were atrazine, bromacil, diuron, simazine, terbuthylazine, terbumetone, terbutryn and trifluralin. Water samples from wells in the orchards were also analysed. The concentrations of the herbicides were very low, often below the limit of determination, and were always highest in the upper layers of soil. After a very unusual period of heavy rain, small quantities of some chemicals were found in the well water. The conclusion was that in these orchards the herbicides applied at currently used rates are unlikely to accumulate in any layers of the soil.  相似文献   

6.
Mechanical incorporation of a tank mixture of trifluralin in combination with fluometuron, diuron or prometryne in the soil to a depth of 10 cm protected emerging cotton from the damage caused by these herbicides in the absence of trifluralin. The incorporated tank mixtures, which were activated by sprinkler irrigation, controlled weeds which were tolerant to trifluralin alone. The different reaction of weeds and cotton to the soil-incorporated herbicide mixtures corresponded to the reaction of their root systems to trifluralin. Weeds whose root system was shortened significantly by trifluralin were sensitive to the tank-mixed, soil-incorporated herbicides. La trifluraline incorporée au sol protége le coton (Gossypium hirsutum) des herbicides à absorption racinaire L'incorporation mécanique de mélanges de trifluraline avec du fluométuron, du diuron ou de la prométryne, à des profondeurs de sol 10 cm, protégeait le coton au moment de la levée contre les dommages occasionnés par ces herbicides en l'absence de trifluraline. Les mélanges incorporés, quiétaient activés par irrigation par aspersion, détruisaient les mauvaises herbes qui étaient tolérantes à la trifluraline seule. La réaction différente des mauvaises herbes et du coton aux mélanges d'herbicides incorporés correspondait à la réaction de leur système racinaire à la trifluraline. Les mauvaises herbes dont le systéme racinaire était raccourci par la trifluraline étaient sensibles aux mélanges d'herbicides incorporés. Schutz der Baumwolle (Gossypium hirsutum) vor wurzelabsorbierten Herbiziden durch eingearbeitetes Trifluralin Nach Einarbeitung von Tankmischungen von Trifluralin mit Fluometuron, Diuron oder Prometryn bis in 10 cm Bodentiefe blieben Baumwoll-Keimpflanzen von den sonst von diesen 3 letzgenannten Herbiziden verursachten Schaden frei, Mittels der Tankmischungen ließen sich gegenuber Trifluralin allein unempfindliche Unkrauter bekampfen. Die unterschiedliche Reaktion der Unkrauter und der Baumwolle auf die eingearbeiteten Herbizidmischungen entsprachen der Reaktion ihrer Wurzeln auf Trifluralin. Soweit die Entwicklung von Unkrautwurzeln durch Trifluralin signifikant gehemmt wurde, waren diese Arten gegenuber den eingearbeitenen Tankmischungen empfindlich.  相似文献   

7.
Abstract

An ICI survey of the arable area of southern Brazil in 1971 confirmed the urgent need for some form of conservation tillage system for soyabean wheat primarily to control soil erosion. A practical system of no-tillage soyabean was developed for N. Parana, with weed control based on careful crop residue management and sprays of paraquat mixed with either linuron or metribuzin. The marked superiority of these mixtures over paraquat alone for the control of vigorous annual grasses was noted. This effect is, in part attributed to the capacity of metribuzin and linuron (along with other herbicides) to inhibit photosynthesis, thereby facilitating the translocation of paraquat. Where residual herbicides are not used, diuron at low rates in suitable formulation proved the best additive for paraquat. Problem broadleaved weeds are controlled by adding 2, 4-D to paraquat. Temperature, rainfall, the presence of fallows and the interval between harvest and the next planting, all affect pre-plant weed control for no-till soyabean. A key issue is to prevent excessive stands of weeds. Control within the crop can be provided by shielded, directed sprays of paraquat for which tractor mounted sprayers were developed. Recent discoveries of pre- and post-emergence selective herbicides provide improved and alternative in-crop weed control options. Crop diversification and further general no-till research show promise of further rational, chemical and cultural methods of weed control.  相似文献   

8.
In 1997 and 1998, five field studies were conducted at four Portuguese wine‐growing regions in order to evaluate the effectiveness of the chemical control of vineyard weeds under Mediterranean conditions using either reduced doses of residual herbicides or only foliar herbicides. Amitrole (3440 g a.i. ha?1), amitrole + glyphosate mono‐ammonium salt (1720 + 900 g a.i. ha?1), amitrole (3400 g a.i. ha?1), amitrole + diuron (2580 + 1500 g a.i. ha?1), amitrole + simazine (2580 + 1500 g a.i. ha?1), amitrole + terbuthylazine (2580 + 1500 g a.i. ha?1) and amitrole + diuron + simazine (2580 + 1300 + 1400 g a.i. ha?1) were assayed and compared with the following reference herbicides: glyphosate isopropylamine salt (1800 g a.i. ha?1), amitrole + diuron (2520 + 1680 g a.i. ha?1), diuron + glyphosate + terbuthylazine (1275 + 900 + 1425 g a.i. ha?1), amitrole + simazine (1900 + 3900 g a.i. ha?1) and glyphosate + simazine (800 + 2200 g a.i. ha?1). The herbicides were applied during late winter. The results indicated that good control was achieved by the application of foliar herbicides alone or of reduced rates of a mixture of residual herbicides with foliar herbicides for at least 2 months. Three months after application, the efficacy of post‐emergence herbicides and lower rates of residual herbicides decreased significantly in clay soils and under heavy rainfall conditions. Convolvulus arvensis– a weed that is becoming increasingly significant in Portuguese vineyards – was poorly controlled, even when glyphosate was used. Despite this, it can be assumed that in those regions in which the trials were conducted, it is possible to employ weed control strategies that entail the elimination or a reduction in the rate of residual herbicides.  相似文献   

9.
眼子菜(Potamogeton tepperi A.Benn.)是我省稻田中普遍发生的多年生恶性杂草,为害严重,人工很难除尽。本文是1972—1973年的研究结果。对眼子菜的形态特徵,特别是根茎与茎芽,作了详细的观察和描述。通过研究其分布与为害、发生周期、繁殖与蔓延、各生育期的特点等生物学特性,明确了支茎初发绿叶时,开始进入光合营养期,此时植株幼嫩,抗药力弱,为化学防除的有利时期。试验确定了扑草净、利谷隆、敌草隆、西草净等除草剂在我省各类稻作区安全、高效的用量范围以及混用方法。以昆明地区为例,模拟分析药性、草情、苗情、环境特点的相互关系,提出栽秧后20—40天为我省施药适期范围,以眼子菜由红叶期转入绿叶期时为指标,并经实践验证,这是可靠的。因地制宜地掌握用药量和施药适期,管好田水,可获得安全、高效、经济与省工、增产的效益。在全省已大面积推广应用,深受群众欢迎。  相似文献   

10.
The effect of the herbicides di-allate, diquat, diuron, paraquat, tri-allate and trifluralin, at a range of application rates from 0.5 to 32 times that recommended by the manufacturers, on vesicular-arbuscular (V-A) endophyte spore abundance in the soil and on infection of wheat roots was investigated in field and glasshouse experiments. Paraquat and diquat had no measurable effect on V-A endophyte spore abundance. There was a slight trend to lower V-A endophyte spore numbers at high rates of application of di-allate and tri-allate but no trend for the other chemicals. Infection intensity (% root length infected) declined at high rates of di-allate and led to lower mycorrhizal root weights. The phosphorus content of the shoots was also reduced by di-allate. High doses of di-allate, diuron, tri-allate and trifluralin reduced most parameters of plant growth more than mycorrhizal parameters. It is therefore concluded that at normal application rates these chemicals are unlikely to affect adversely endomycorrhiza formation or function.  相似文献   

11.
Summary. A comparison was made between diphenamid and napropamide with regard to phytotoxicity to pepper and weeds under glasshouse and field conditions. Diphenamid was considerably less phytotoxic than napropamide in inhibiting root elongation and shoot growth of pepper seedlings. Plant growth was reduced when the roots were exposed to either one of the herbicides, but growth of the shoot through treated soil was not adversely affected. Since diphenamid was found to be more leachable into soil, it might become more available to the roots and damage the crop plants. Graminaceous weeds were very sensitive to both herbicides, whereas several dicotyledonous weeds were more susceptible to napropamide. Selectivity of both herbicides at a late pre-emergence application to direct-seeded pepper was found satisfactory in two field experiments on different soil types.
Action sélective de la diphénamide et de la napropamide sur le piment et les mauvaises herbes  相似文献   

12.
Abstract

Results are given of a trial in which trifluralin, incorporated in the soil, at rates of 0.5 and 0.75 kg/ha, was combined with fluometuron at 1.6 kg/ha, and with prometryne at 1.0 kg/ha, both incorporated, pre- and post-em. and with noruron + MSMA (1.0:2.2) at 1.7 kg/ha post-em.

Best results were given by incorporated treatments of trifluralin + fluometuron (0.5 + 1.6) kg/ha, or by trifluralin incorporated at 0.5 or 0.75 kg/ha + fluometuron applied pre-em. at 1.6 kg/ha, or by trifluralin incorported at 0.75 kg/ha + prometryne applied pre-em. at 1.0 kg/ha.

It is recommended that noruron + MSMA (1.0:2.2) at 1.7 kg/ha be applied post-em. as a complementary treatment to trifluralin at 0.5 kg/ha in fields where Cyperus spp. are a problem.  相似文献   

13.
J. ZEMANEK 《Weed Research》1969,9(4):265-271
Summary. In a field trial of modified logarithmic design, NaTCA and dalapon were applied pre-sowing and pyrazon and lenacil were applied pre-emergence. There were five rates of application and each pair of herbicides (NaTCA + pyrazon, dalapon + pyrazon, NaTCA + lenacil and dalapon-|- lenacil) had thirty-six variants. NaTCA and dalapon alone were found to have some effect on the dicotyledons. Increasing rates of NaTCA and dalapon in combination with pyrazon or lenacil resulted in better weed control, but also had a slight phytotoxic effect on the beet. Because the susceptibility of beet did not increase to the same extent as that of the weeds with the combined treatments examined, the selectivity under the conditions of the experiment was at least not reduced.
L'interaction entre Us herbicides appliqués en pri-semis et en pri-levée dans la betterave à store  相似文献   

14.
Summary. Herbicide combinations containing paraquat were synergistic and provided control of established Agropyron repens (L.) Beauv. (quackgrass) sods for the entire growing season. Paraquat applied at 0–5 lb/ac with simazine or diuron at 4–0 lb/ac was more phytotoxic than either herbicide applied singly and the enhanced activity was more than additive. This synergism was not due to increased absorption or translocation of either herbicide in aerial portions of the plant. Paraquat applied to the shoot increased the susceptibility of quackgrass to simazine action through the soil. Pre-treatment of quackgrass with aminotriazole or amitrole-T at 10 lb/ac 7 days before paraquat application at 0–5 lb/ac provided increased toxicity over that obtained when the two herbicides were applied together or singly. Subsequent studies indicated that aminotriazole applications prior to shoot destruction by either paraquat or clipping resulted in more chronic aminotriazole toxicity. Using methyl-14C-paraquat it was found that aminotriazole pre-loading also increased the movement of paraquat in and out of the treated leaf. This increase was even more pronounced with amitrole-T. When the two herbicides were applied together, antagonism in absorption and translocation occurred. Action synergique de combinaisons d'herbicides comprenant du paraquat sur Agropyron repens (L.) Beauv.  相似文献   

15.
Abstract

Early work on chemical weed control in the fallow towards the end of the Second World War is reviewed briefly. Attempts to use contact residual herbicides as pre-emergence applications in the early 1950s are also described.

Pre-sowing applications of residual herbicides were found more phytotoxic to cotton than pre-emergence applications. The closer the time of pre-sowing application to cotton sowing, the more effective was suppression of weeds competing with cotton.

Mechanical cultivations and particularly disc ploughing and rotovation to a depth of more than 15 cm were found more effective in the control of Cynodon dactylon than pre-sowing herbicide applications.

Fluometuron, noruron and prometryne were found very effective as pre-emergence herbicides. Optimum rates of application were found to be only 25-50% of rates recommended for the USA and other countries. Resistant weeds included Cyperus rotundus, Cynodon dactylon, and Rhyncosia memnonia.

A large-scale trial with fluometuron, covering 125 feddans at Wad el Nairn showed that yields obtained were equal to those with normal weeding. Costs of herbicide treatments were also comparable to costs of hand-weeding in a year of exceptionally low hand-weeding costs.  相似文献   

16.
The effects on plant growth of applying trifluralin or nitralin combination with simazine, atrazine, prometryne and linuron to the upper 5-cm root region of vetch (Vicia sativa L.), pea (Pisum sativum L.) and soybean (Glycine max) were investigated. Foliar injury due to herbicides of the second group was markedly reduced in each species by simultaneous treatment with trifluralin or nitralin both of which inhibited lateral root growth without affecting aerial plant growth or tap root extension growth. This inhibition of lateral root growth in roots treated with trifluralin or nitralin was associated with reduced uptake and subsequent transport to the foliage of 14C-labelled simazine in vetch and pea and 14C-labelled atrazine in soybean. This probably accounted for the reduction in simazine and atrazine phytotoxicity. In the presence of trifluralin or nitralin comparatively higher amounts of radioactivity were retained in the roots of pea and soybean and this reduced the amount of 14C available for transport to the foliage. This was not evident in vetch.  相似文献   

17.
Trials were conducted at the research farm of the National Root Crops Research Institute, Umudike, on acid sandy loam soil at a tropical rainforest site during 1982 and 1983. A range of pre-emergence herbicides were evaluated in a system of yam production using small (25 g) tuber pieces, ‘minisetts’, for multiplication up to ‘seed’ yam size with tubers of 100–1500 g wt. In the 2 years considered, uncontrolled weed growth resulted in an average tuber yield loss of 83% compared to the hand-weeded treatment yield of 3.6 t ha?1. Pre-emergence application of fluometuron, chloramben, diuron/paraquat, simazine and atrazine/metolachlor at the rates of 1.4, 2.7, 1.6, 5.7 and 3.8 kg ai ha?1 respectively effectively controlled weeds and gave tuber yields that compared favourably with the current recommended practice of three hand-weedings 3, 8 and 12 weeks after planting. These five herbicides were most promising when they were applied tank-mixed with paraquat at 0.5 kg ai ha?1 3 weeks after planting, post-emergence to the weeds and at approximately 5% emergence of the yam. Des herbicides pour la production d'ignames ‘minisetts’ dans la zone forestière humide du Nigéria Des essais ont été mis en place en 1982 et 1983 à la ferme du National Root Crops Research Institute, Umudike, sur un sol franc sablonneux acidique de la zone forestière humide. Une gamme d'herbicides de pré-levée a étéévaluée dans un système de production utilisant des petits morceaux (25 g) de tubercules d'ignames, dits des ‘minisetts’, dans le but de multiplication jusqu'à ce qu'ils atteignent la grandeur d'ignames semences'. Pendant les deux années de l'expérimentation, l'absence de désherbage a amené des baisses de rendement en tubercules de 83% par rapport au rendement de 3,6 t obtenu avec sarclage manuel. L'application en pré-levée de fluométuron, de chloramben, de diuron/paraquat, de simazine et d'atrazine/métolachlore aux doses de 1,4, 2,7 1,6 5,7 et 3,8 kg m a ha?1 respectivement a permis un désherbage convenable et des rendements en tubercules supérieurs à ceux obtenus par la technique actuellement conseillée, qui comporte trois sarclages manuels à 3,8 et 12 semaines après le semis. Ces cinq herbicides ont fourni les meilleures perspectives d'efficacité lors d'applications en mélange avec le paraquat à 0,5 kg ma ha?1 3 semaines après le semis, en post-levee des adventices et lorsqu'à peu près 5% des ignames sont levées. Prüfung von Herbiziden in der Saatknollen Produktion von Yams in der Regenwaldzone von Nigeria In der Forschungsstation des National Root Crops Research Institute, Umudike (Nigeria), wurden während der Jahre 1982 und 1983 verschiedene Herbizide auf ihre Eignung zur Unkrautbekämpfung in Anlagen zur Produktion von Saatknollen von Yams untersucht. Die Versuche erfolgten unter den Bedingungen des tropischen Regenwaldes in einem sauren, sandigen Lehmboden. Ausgangspunkt der Pflanzung waren 25 g schwere Knollenstückchen (sog. ‘Minisetts’), welche bis zur Grösse der Saatknollen (von 100–1500 g Gewicht) wachsen gelassen wurden. Die von Hand gejäteten Parzellen lieferten einen Ernteertrag von 3,6 t ha?1; das unkontrollierte Unkrautwachstum verursachte einen Ernteverlust von 83%. Die Vorauflaufapplikation von Fluometuron, Chloramben, Diuron + Paraquat, Simazin und Atrazin + Metolachlor, in Dosierungen von 1,4, 2,7, 1,6, 5,7 und 3,8 kg ai ha?1 bewirkte eine befriedigende Unkrautkon-trolle und ergab Knollenernten, die mit den durch die ortsübliche Praxis (3 Handjätungen 3, 8 und 12 Wochen nach der Pflanzung) erzielten Ernten vergleichbar waren. Diese fünf Herbizide waren am erfolgreichsten, wenn sie in Tankmischung mit Paraquat (0,5 kg ai ha?1) drei Wochen nach der Pflanzung, nach Auflaufen der Unkräuter und beim Erscheinen von c. 5% der Yamstriebe appliziert worden waren.  相似文献   

18.
Summary. Pre-emergence application of 2–5 kg/ha (a.i.) of atrazine or simazine was the most effective treatment for control of broad-leaved weeds in maize. Other triazines injured maize at all rates tested. Among the crops following maize treated with atrazine or simazine at 2–5 kg/ha, sugar beet was injured whereas wheat, oats, vetch, onions and soybeans were not. Post-emergence application of triazine herbicides was not effective and did not increase maize yields significantly over those of the unweeded plots. Wheat, oats, vetch and sugar beet were injured when following maize treated with post-emergence sprays; onions and soybeans showed no visible injury except from atrazine or simazine at 5 kg/ha or more, and from mixtures of atrazine+prometryne or atrazine+ametryne at 12–5 kg/ha. Les triazines herbicides sur le mais et leurs arrière-effets sur les cultures suivantes  相似文献   

19.
Abstract

The effectiveness of butralin (2.0 and 4.0 kg a.i./ha pre-plant, 2.0 and 4.0 kg a.i./ha pre-em), chlorthal-dimethyl (10.0 and 12.0 kg a.i./ha pre-em), trifluralin (0.6 and 1.1 kg a.i./ha pre-plant) chloramben (2.0 kg a.i./ha pre-em) and nitrofen (2.0 kg a.i./ha pre-em) in controlling weeds in transplanted ‘Kono Cross’ cabbage and the influence of these treatments on the yield and quality of marketable heads and on the economics of weed control were evaluated in three replicated field experiments on River Estate loam soil in Trinidad during the wet seasons of 1976 and 1977. While herbicides did not affect the size of the cabbage plant population or the date to maturity of the crops, they reduced the cost of weed control by over 30% and increased the net returns relative to the clean-weeded control by over 9%. Butralin at 4.0 kg a.i./ha pre-plant and pre-em and the trifluralin treatments were superior to nitrofen which gave good weed control up to five weeks and higher yields than the clean-weeded control. Chlorthal-dimethyl gave encouraging results but caused slight, temporary stunting. The application of one of these treatments followed by one hand weeding at about four weeks should give full-season weed control and an acceptable yield of marketable heads with increased financial returns. Chloramben was the least effective herbicide tested and its use may not be justified under similar conditions to those of this study.  相似文献   

20.
Weed control, an important practice in agroecosystems to protect crop production, is usually achieved with herbicides. However, these pesticides are expensive, pose potential risks to the environment, may affect some beneficial organisms indirectly, and decrease overall arthropod biodiversity, including pests and their natural enemies, by removing weeds that might act as hosts or shelters for many organisms. The activity density response of important surface-dwelling arthropod predators (ground beetles [Coleoptera: Carabidae], ants [Hymenoptera: Formicidae] and spiders [Arachnida: Araneae]) to herbicides (trifluralin and paraquat), and to two alternative weed management practices (rye straw mulch and mechanical treatment to maintain weeds below threshold levels, in comparison with an untreated check), was assessed using pitfall traps. The mulch treatment had the greatest effect on activity density, reducing the number of predators trapped significantly (P<0.05). Herbicide use resulted in significant (P<0.05) reductions in the activity density of ground beetles. Most predators were trapped in the check plots — which had the highest weed biomass, followed in turn by numbers trapped in the threshold weed control treatment, the full herbicide application and the mulch treatment plots. http://www.phytoparasitica.org posting July 10, 2002.  相似文献   

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