bluuebunny/crossref_metadata_2025 huggingface dataset:
The effect of temperature and water content on the rate of decomposition of the herbicide linuron in soil
Authors: USOROH N. J. , HANCE R. J.
Published: July 2006

Summary: Résumé: Zusammenfassung

Rates of linuron breakdown were measured in soil held at the water‐holding capacity (WHC), ½ WHC and WHC and at two temperatures, 4°C or 22°C. Breakdown rates were greater at the higher temperature and increased with water content. The energy of activation for the degradation was calculated. Comparison with published figures leads to the speculation that the initial step in degradation by microorganisms is different from that in chemical processes.

Effet de la température et de la teneur en eau sur le taux de decomposition du linuron dans le sol

Les taux de dégradation du linuron ont été mesurés dans un sol maintenu à sa capacité de rétention, à la moitié et au quart de cette capacité, ainsi quà deux températures 4°C ou 22°C. Les taux de dégradation furent plus grands à la tem‐pérature la plus haute et augmentérent avec la teneur en eau. L'energie d'activation pour la dégradation a été calculée. La comparaison avec des chiffres publiés conduit à penser que la première étape de la dégradation par des microorganismes est differente de celle qui intervient dans le processus chimique.

Abbau von Linuron im Boden in Abhangigkeit von Temperatur mid Wassergehalt

Der Abbau von Linuron im Boden wurde bei 100%, 50% und 25% Wasserkapazitat und bei zwei Termperaturstufen (4°C und 22°C) untersucht. Die Abbauraten nahmen mit steigender Temperatur und steigendem Wassergehalt des Bodens zu. Die fur den Abbau erforderliche Aktivierungs‐energie wurde errechnet. Ein Vergleich der Ergebnisse mit Literaturangaben fuhrt zu der Vermutung, daβ der erste durch Mikrooganismen verursachte Abbauschritt verschieden ist von dem bei rein chemischem Vorgang.
Loss of acrolein from water by volatilization and degradation
Authors: BOWMER KATHLEEN H. , LANG A. R. G. , HIGGINS M. L. , PILLAY A. R. , TCHAN Y. T.
Published: July 2006

Summary: Résumé: Zusammenfassung

The loss of acrolein by volatilization and degradation from a large tank of water is described. The standard analytical method for carbonyl compounds, a colorimetric reaction with dinitrophenylhydrazine did not distinguish acrolein from a relatively non‐volatile and non‐toxic reaction product. In a modification of the method to correct the error, acrolein was separated from reaction products by scrubbing with air. Although acrolein is sufficiently volatile to use air‐scrubbing to separate it from reaction products, its loss by evaporation from an open tank was much less than its loss by reaction in the local irrigation water. In other waters differences in chemical properties could affect the loss of acrolein by reaction, and greater turbulence is expected to increase loss by volatilization.

Perte d'acroléine à partir de l'eau par volatilisation et dégradation.

Les auteurs décrivent la perte d'acroléine par volatilisation et degradation k partir d'un grand reservoir d'eau. La methode analytique standard pour les composes carbonyl. une reaction colorimétrique avec la dinitrophenylhydrazine. n'a pas permis de distinguer l'acroléine d'autres produits relativement non volatils et non toxiques, apparaissant au cours de la reaction. Dans une modification de la méthode en vue de corriger l'erreur. l'acroléinc a été séparée des autres products de la reaction au moyen d'un entrainement par fair. Bien que l'acroléne soit suffisamment volatile pour que Ton puisse utiliser l'air pour la séparer des autres produits de la reaction, la perte par évaporation à partir d'un réservoir ouvert s'est avérée beaucoup moindre que la perte par reaction dans l'eau d'irrigation apportée localement. Dans d'autres CAS, des differences dans les proprióteschimiques peuvent affecter la perte d'acroléine au cours de la reaction de la faut s'attendre à un accroissement de la perte par volatilisation dans le cas d'une turbulence plus grande.

Verlust von Acrolein durch Verfükhtigung und Abbau in Wasser

Es wird der Verlust an Acrotein aus einem grossen Wassertank durch Verdampfung und Abbau beschrieben. Die analytische Standardmethode für Carbonylverbindungen mit Dinitrophenylhydrazin, lässt keine Unterscheidung zwischen Acrolein und einem verhältnismässig wenig flüchtigen und un‐giftigen Reaktionsprodukt zu. Um die Fehlermöglichkeit Zu eliminieren. wurde die Methode abgeándert, indem das Acrolein von den Reaktionsprodukten durch “Auswaschen” mit Luft abgetrennt wurde, Obgleich die Flüchugkeit von Acrolein genúgend gross ist. um es durch “Auswaschen” mit Luft von Umsetzungsprodukten abzutrennen. ist der durch seine Verdampfung aus einem offenen Tank verursachte Verlusl viel geringer als der durch Umsetzung im lokalw Beregnun‐swasser bedingte. In anderen Wassern könnten Unterschiede in den chemischen Eigenschaften den Verlust von Acrolein durch Umsetzung beeinflussen und es ist zu erwarten. dass grössere Turbulenz die Abnahmc durch Verflüchligung erhöht.
The allelopathic activity of Californian thistle (Cirsium arvense (L.) Scop.) in Tasmania
Authors: ALL G. M. BEND
Published: July 2006

Summary: Résumé: Zusammenfassung

The phytotoxicity of extracts from the roots and foliage of Cirsium arvense (L.) Scop, was studied using seven test species. Water and alcohol extracts of C. arvense inhibited the germination of its own and Trifolium subterraneum L. seed, and inhibited the growth of its own seedlings, three annual thistles, and Lolium perenne L., T. subterraneum and Hordeum distichon L.

The results are related to phytosociological patterns observed in the field, and it is suggest that the presence of phytotoxins in the soil may make the establishment of some pasture and crop species difficult in areas infested with C. arvense.

Activité allélopathique du chardon Cirsium arvense L. Scop, en Tasmanie

La phytotoxicityé d'extraits obtenus à partir des racines et du feuillage de Cirsium arvense (L.) Scop, a étéétudiée en tulisant sept espèces servant de tests. Des extraits aqueux et alcooliques de C. arvense inhibèrent sa propre germination et celle des semences de Trifolium subterraneum L. Ils inhibèrent également la croissance de ses propres plantules, de trois chardons annuels, de Lolium perenne L. de T. subterraneum et de Hordeum distichon L.

Les résultats sont rapprochés des évolutions phytosociologiques observées au champ, et il est suggéré que la présence de phytotoxines dans le sol puisse rendre difficile l'implantation de certaines espèces fourragères ou autres dans les endroits infestés par C. arvense.

Die allelopathische Aktivität von Cirsium arvense (L.) Scop. in Tasmanien

Wurzel‐ und Blattextrakte von Cirsium arvense (L.) Scop. wurden auf ihre phytotoxische Wirkung mit sieben Test‐pflanzen geprüft. Wasser‐ und Alkoholauszüge von C. arvense hemmten die Keimung der eigcnen und der Samen von Trifolium subterraneum L. Das Wachstum der eigenen Keimlinge, sowie von drei annuellen Distelarten, von Lolium perenne L., T. subterraneum und von Hordeum distichon L, wurde gehemmt.

Die Ergebnisse zeigen einen Zusammenhang mit pflanzensoziologischen Feldbeobachtungen und es ist denkbar, dass die Gegenwart von Phytotoxinen im Boden den Aufwuchs von Grünlandpflanzen und Feldfrüchten in Fiächen, die mit C. arcense verseucht sind, erschweren kann.
Competition between Cyperus difformis and rice: the effect of time of weed removal
Authors: SWAIN D. J. , NOTT M. J. , TROUNCE R. B.
Published: July 2006

Summary: Résumé: Zusammenfassung

Experiments in which Cyperus difformis L. was removed from rice (Oryza sativa L.) by hand al various stages of crop growth demonstrated severe competition between the weed and the crop. Where high populations of C. difformis competed with the rice for the whole of the growing season rice yields were reduced by 22% to 43%. Yield reduction caused by competition was greater under conditions of higher soil fertility.

Competition entre Cyperus difformis et le riz; effet de l’épogue du sarclage

Des expériences dans lesquelles Cyperus difformis L. a été enlevéà la main d'une culture de riz (Oryza sativa L.), à divers stades de la croissance de celui‐ci, ont révélé une compétition importante entre la mauvaise herbe et la culture. Là où des populations denses de C. difformis ont exercé leur compétition envers le riz pendant toute la durée la saison de croissance, les rendements du riz oni été réduits de 22%à 43%. La réduction de rendement provoquée par la compétition a été plus forte dans des conditions de fertilité du sol plus élevée.

Konkurrenz zwischen Cyperus difformis und Reis: Einfiuss des Zeitpunktes der Unkrautentfernung

In Versuchen in denen Cyperus difformis L. von Hand aus Reis (Oryza sativa L.) zu verschiedenen Entwicklungsstadien der Kulturpflanze entferenl wurde, verdeuiIk hten die starke Konkurrenz zwischen Unkraut und Kulturpflanze.

Wo viele C. difformis‐Pflanzen mil Reis über die ganze Vegetalionsperiode konkurrierten, gingen die Reiserträge um 22% bis 43% zurück. Die Ertragsernicdrigung war durch die Unkrautkonkurrenz unter Bedingungen hoher Boden‐fruchtbarkeit stärker.
Genetic variation in herbicide resistance in scentless mayweed (Tripleurospermum inodorum (L.) Schultz Bip.) III. Selection for increased resistance to ioxynil, MCPA and simazine
Authors: Ellis M. , KAY Q. O. N.
Published: July 2006

A sample of 100 seedlings from a weed population of T. inodorum which had been found to be relatively sensitive to MCPA was exposed to an MCPA concentration sufficient to give a 38% kill, and the five most vigorous survivors were combined in a polycross. When sprayed with MCPA, the progeny of the polycross had an LD50 15·4% greater and a mean fresh weight per plant 30·2% greater than that of unselected controls. In a similar selection among plants from the same population for ioxynil resistance, the initial kill was 81% and (he progeny of selected plants had an LD50 77·3% greater and a mean fresh weight per plant 43·3% greater than that of unselected controls; and in a similar selection for simazine resistance, the initial kill was 99% and the progeny of a selected plant had an LD50 17·0% greater and a fresh weight per plant 88·4% greater than that of unselected controls. The increase in resistance to MCPA and ioxynil was less than the differences between populations observed in previous screenings, and the selected plants were considerably less resistant than the most resistant wild populations.
Experiments with Cyperus rotundus L. III. Seasonal variations in growth
Authors: Hammeron John L.
Published: July 2006

Nutgrass tubers were planted in pots on thirteen occasions at 4‐weekly intervals, and growth and development followed by sampling at 5‐day intervals from 10 to 45 days after planting. Growth rates, final shoot numbers, dry weights and rhizome lengths, and new tuber production were highest in plantings made 1 and 29 March and 26 April. Correlation coefficients suggested that mean daylength during growth was a major factor influencing growth and development, but mean temperature appeared to be important in determining new tuber size and the proportion of dry‐matter as new tubers. Shoot number appears to be a reliable guide to rhizome and tuber production.
Some aspects of the absorption of picloram by gorse (Ulex europaeus L.)
Authors: ROLSTON M. P. , ROBERTSON A. G.
Published: July 2006

Plants of Ulex europaeus were grown from cuttings and studies made of the absorption of 14C‐picloram applied with unlabelled 2,4,5‐T. In vivo experiments in a growth chamber showed that absorption ceased after 10 h, but was resumed on wetting. In in vitro experiments the Q10 and the activation energy for uptake decreased with increasing temperature. Absorption was increased by addition of non‐ionic surfactants, by lowering the pH and by removal of cuticular wax. Gorse shoots were shown to have a high wax content but scanning electron microscopy revealed no obvious wax structures and the contact angle of spray droplets was less than 900, indicating that the surfaces were not difficult to wet.
Field degradation of the herbicide metribuzin and its degradation products in a Manitoba sandy loam soil*
Authors: WEBSTER G. R. B. , REIMER G. J.
Published: July 2006

The degradation of the herbicide metribuzin (4‐amino‐6 r‐butyl‐3‐(methylthio)‐1, 2, 4‐tnazin‐5‐(4H)one) applied at 1 and 2 kg/ha at times equivalent to pre‐emergence (12 June), post‐emergence (5 July), and pre‐harvest (15 August), has been investigated in Almasippi very line sandy loam at Carman, Manitoba. Gas‐liquid chromatographic analytical results showed that metribuzin degraded during the growing season, and that residue levels immediately prior to freeze‐up (25 October) were in general less than 10% of applied metribuzin independent of application date, and were largely unchanged the following spring.

The metabolites and photoproduct of metribuzin were present in maximum amounts near 13 July for the first two treatment dates, a time closely following maximum soil temperature readings, and these compounds in turn degraded almost completely by freeze‐up. The following spring only very low levels were detected. Under the conditions described, metribuzin and its degradation products degraded to low levels and should not provide a carryover problem the next growing season.
The efficiency of herbicide incorporation into soil with different implements
Authors: WALKER A. , FARRANT D. M. , BRYANT J. H. , BROWN PAULINE A.
Published: July 2006

The distribution of trifluralin in soil was measured following its incorporation with the rotavator, rotary power harrow, reciprocating harrow, spring‐tined harrow, tandem disc cultivator and drag harrow. A single pass with the rotavator gave an even distribution In the top 5 cm of soil and similar results were obtained by cross cultivations with the rotary power harrow, reciprocating harrow, spring‐tined harrow and disc cultivator. A single cultivation with the spring‐tined harrow, reciprocating harrow and rotary power harrow left much of the herbicide close to the soil surface as did both a single and cross cultivation with the drag harrow. With the tandem discs, although a single pass did incorporate the herbicide, a cross cultivation was necessary to ensure that incorporation was even enough across the treated area. A single pass of the rotavator gave a uniform mixing throughout its working depth, whereas cross cultivations with each of the other implements gave a relatively uniform mixing to about half of their working depth.
Adsorption et désorption de la terbutryne par une montmorillonite‐Ca et des acides humiques seuls ou en mélanges
Authors: GAILLARDON P. , CALVET R. , TERCE M.
Published: July 2006

L' effet du pH sur l'adsorption de la terbutryne par des acides humiques, une montmorillonite‐Ca ou leurs mélanges montre une certaine similitude de comportement entre ces derniers et l'argile seule. Au voisinage de la neutralité, seuls les acides humiques adsorbent la terbutryne. En milieu acide, les isothermes d'adsorption de la terbutryne par les acides humiques et la montmorillonite sont respectivement de type L et S et traduisent une affinité adsorbat‐adsorbant différente; les isothermes d'adsorption correspondant aux mélanges ont une forme différente et font apparaitre un effet de synergie, en particulier dans le cas des mélanges pauvres en acides humiques. La dsorption šaccompagne d'un phénoméne d'hystérésis lieA à la présence des acides humiques. Les propriétés particulières des associations argiles‐matiéres organiques sont susceptibles de mieux expliquer l'effet des sols sur l'activité des herbicides.
Extraction, purification et caractérisation de résidus de piclorame, dicamba ou TBA à partir de pailles ou de mélanges terreux
Authors: DUMAS E. , VALLEE J. C. , MARTIN C. , VANSUYT G. , VERNOY R.
Published: July 2006

La mise au point d'une méthode de recherche de résidus de piclorame dans des pailles seules ou mélangées à de la terre, combinant l'utilisation de tests biologiques à des méthodes biochimiques simples et classiques, fait l'objet de la présente communication. Cette méthode, suffisamment fiable et précise en ce qui concerne le piclorame, permet en outre de déterminer si des mélanges terreux ou des pailles contiennent d'autres herbicides de type phytohormonal.
The adsorption of atraton and monuron by soils at different water contents
Authors: HANCE R. J.
Published: July 2006

Estimates of adsorption by soil at water contents down to less than wilting point were obtained with a three phase system of soil‐water‐immiscible organic solvent. The method is restricted to solutes with a water‐organic solvent partition ratio of between about 10 and 0.5 if analytical errors are to be acceptable. With the two soils used the results with atraton and monuron were similar. There was little change in adsorption as soil water content was reduced until the level approached that needed to produce a monolayer on the soil surfaces, when it increased sharply. There were no differences at water contents between field capacity and wilting point.
Chemical control of marsh ragwort (Senecio aquaticus Huds.) in established grassland
Authors: FORBES JAMES C.
Published: July 2006

Infestations of marsh ragwort, Senecio aquaticus Huds., in established ley grassland were sprayed at the rosette stage in April or May with MCPA, 2,4‐D, asulam or a 2,4‐D asulam mixture. All treatments gave better control in the year after spraying than in the year of spraying. The most effective herbicide was 2,4‐D ester at 1–68 or 1–12 kg/ha with or without the incorporation of asulam at 1–12 kg/ha. MCPA at 1–68 kg/ha was less effective, especially in the year of spraying and asulam alone at 1‐12 kg/ha gave consistently the poorest control of all treatments. Spraying in May gave better control in the year of spraying than April application, but in the year after spraying date of application made no difference to the degree of control. S. aquaticus at the various sites differed in general susceptibility to herbicides in the year of spraying, but in the year after spraying these differences disappeared.
Effect of four herbicides and two oils on leaf‐cell membrane permeability*†
Authors: PRENDEVILLE G. N. , WARREN G. F.
Published: July 2006

Leakage of electrolytes from leaf discs of treated Phaseolus Vulgaris L. plants was the main criterion used to study the effect of several chemicals on the permeability of leaf‐cell membranes. Paraquat, diquat, dinoseb and oxyfluorfen (2‐chloro‐1‐(3‐ethoxy‐4‐nitrophenoxy)‐4‐(Trifluoromethyl) benzene) increased leaf‐cell membrane permeability after exposure for 12 h or less. An‘aromatic’oil caused a large increase in permeability at 2–5 min after treatment. Increases in electrolyte release were also correlated with release of soluble amino acids from the leaf discs but the former method was the more sensitive. Increase in cell membrane permeability was always associated with injury symptoms such as appearance of necrotic areas in leaves. Chlorpropham, linuron, sodium azide, glyphosate and 2,4‐D at 10−3M, as well as 1% X‐77 surfactant and a non‐phytotoxic isoparaffinic oil did not alter leaf‐cell permeability at 12 h after treatment.

Light was necessary for paraquat and oxyfluorfen to alter leaf cell permeability. Paraquat and oxyfluorfen caused a greater increase in leaf‐cell permeability of a soybean mutant with yellow leaves as compared with the normal green leaves. With oxyfluorfen this difference in permeability was greater than with paraquat, and was associated with the appearance of severe necrotic injury symptoms in the yellow mutant; paraquat caused no injury symptoms.
A preliminary survey of arable weeds in Britain
Authors: CHANCELLOR R. J.
Published: July 2006

Details and results are given of the first of two surveys, which are designed to measure the changes taking place in the incidence of forty species of arable weeds in Britain.
Control of Cirsium arvense (L) Scop, by herbicides and mowing
Authors: AMOR R. L. , HARRIS R. V.
Published: July 2006

The efficacy of mowing and of herbicides (applied by spot spraying or boom spraying) for the selective control of Cirsium arvense (L) Scop, in Victorian pastures was investigated. The pastures were based on Trifolium repens L. and Lolium perenne L.

A general decline in the number of thistle shoots in untreated plots at three out of five sites was recorded.‘Tordon 50‐d' (5% a.i. picloram and 20% a.i. 2,4‐D as triisopropanolamine salts), MCPB, 2,4‐DB and mowing resulted in suppression, but not eradication, during the experimental period. MCPB and 2,4‐DB are the most suitable herbicides for selective control. The use of‘Tordon 50‐d' is restricted by its effect on clovers, soil persistence and cost.

Variable growth of C. arvense, associated with variable summer rainfall in Victoria, increases the difficulty in controlling this weed and necessitates a persistent long term approach.
The nutritive value of Echium plantagineum L. and Trifolium subterraneum L.
Authors: PIGGIN C. M.
Published: July 2006

Echium plantagineum is a widespread, persistent, highly productive and often dominant species in southern Australia. In pastures, it usually occurs with Trifolium subterraneum. which is commonly regarded as a valuable forage species. However, there is considerable controversy over the value of E. plantagineum as a pasture species.

In this study, the nutritive value (dry matter content, in vitro digestibility, nitrogen content) of herbage of E. plantagineum and T. subterraneum generally was similar at any time during the year. It is concluded that E. plantagineum is a useful forage species because it is highly productive, is readily eaten by grazing stock and has a relatively high nutritive value.
Population flux and mortality in a ragwort (Senecio jacobaea L.) infestation
Authors: FORBES JAMES C.
Published: July 2006

Actuarial data on the progress through the life‐cycle and the death of individual plants of Senecio jacobaea in permanent pasture were obtained over a period of one year by repeated mapping of all the plants in twenty permanent quadrats. The data were used to construct a model of population flux and mortality in a hypothetical population in which germination, maturation and death were constant from year to year and equal to those in the real population in the year of study. In the hypothetical population 57% of all plants died as seedlings. 35% as vegetative rosettes and 8% immediately after flowering. Of plants which flowered in the first 2 years or survived into a third year 8% were annuals or winter annuals, 39% were biennials and 53% were perennials.
Tuber composition in yellow nutsedge (Cyperus esculentus (L.)) variants
Authors: MATTHIESEN R. L. , STOLLER E.W.
Published: July 2006

Summary: Résumé: Zusammenfassung

Yellow nutsedge variants from California, Georgia, Illinois, Maryland, Minnesota and Oklahoma were analysed for intraspecific differences in tuber composition. Tuber size varied from 70 to 710 mg. Carbohydrates ranged from 45 to 77% of tuber dry weight. Starch was the most abundant carbohydrate in all the tubers. The saccharides, fructose, glucose, sucrose and melibiose were found at least in trace quantities in all the tubers; only tubers of the Georgia and Maryland variants contained significant quantities of all four saccharides, and the other three variants containted principally sucrose. Triglycerides constituted more than 80% of the lipids in the tubers. The major acid present in all tubers was oleic.

Composition du tubercule chez divers biotypes de Cyperus esculentus (L.)

Des biotypes de Cyperus provenant de Californie, de Géorgie, de l'Illinois, du Maryland, du Minnesota et de l'Oklahoma ont été analysés en vue de rechercher des différences intraspécifiques dans la composition du tubercule. Le poids du tubercule a varié de 70 à 710 mg. Les hydrates de carbone représentaient de 45 a 77% du poids sec du tubercule. L'amidon a été l'hydrate de carbone le plus abondant dans tous les tubercules. Les saccharides: fructose, glucose, saccharose et mélibiose ont été trouvés au moins à l'état de traces dans tous les tubercules; seuls les tubercules des biotypes de Géorgie et du Maryland contenaient des quantités significatives des quatre saccharides et les trois autres biotypes contenaient principalement du saccharose. Les triglycérides constituaient plus de 80% des lipides des tubercules. Le principal acide gras présent dans tous les tubercules était l'acide oléique.

Inhaltsstoffe der Knollen verschiedener Herkünfte von Cyperus esculentus (L.)

Herkünfte von Cyperus esculentus aus Kalifornien, Gorgia, Illinois, Maryland und Oklahoma wurden auf Unterschiede in ihrer Knollenzusammensetzung untersucht. Die Knollenge‐wichte variierten zwischen 70 und 710 mg. Die Kohlenhydratgehalte schwankten von 45 bis 77% des Knollentrockengewichtes. Stärke war in alien Knollen das häufigste Kohlenhydrat. Die Saccharide Fructose, Glucose, Sucrose und Melibiose waren in alien Knollen zumindest in Spuren festzustellen. Lediglich Knollen aus Gorgia und Maryland enthielten größere Mengen aller 4 Saccharide. DieTestlichen 3 Herkünfte enthielten haupt‐sächlich Sucrose. Triglyceride bildeten mehr als 80% der Knol‐lenlipide. Die häufigste Fettsäure war Ölsäure.
The long term decline of a population of Avena fatua L., with different cultivations associated with spring barley cropping
Authors: WILSON B. J.
Published: July 2006

The decline of a population of A. fatua established in September 1971, and not allowed to seed thereafter, was monitored in three successive barley crops Numbers of viable seeds in the son in June fell from 159 m2 in 1972 to 1 m2 in 1974 declining by 83° in the first, and by 96° in the second year. Seedling numbers fell from 138 m2 in 1972 to 9 m2 in 1974, declining by 32° in their first and by 89° in the second year. The slower decline of seedling numbers in the first year was attributed to loss of dormancy of seed reserves giving proportionally more seedlings in the second spring.

Cultivations had no major influence on the pattern of seedling emergence in the spring, but they did affect population level. Where the stubble was cultivated immediately after seeding in September 1971, twice as many seedlings and three times as many seeds in the soil were present in 1972 compared with delayed autumn cultivations in 1971. From this greater reserve of seeds in the soil more seedlings arose in 1973 and in 1974. Time cultivation in the winter of 1971 resulted in slightly more seedlings in 1972 than did ploughing; this greater population declined more rapidly with line cultivation in 1973 and 1974. It is suggested that with no herbicidal control annual line cultivation will lead to a more rapid build up than ploughing: where A. fatua is controlled, the decline should be more rapid with tne cultivation. Persistence of A. fatua as a weed in arable situations seems related more to survivors shedding seeds than to the persistence of seeds on the soil. Factors which may influence the persistence of seeds in the soil are discussed.
Recovery from inhibition of photosynthesis by metamitron in various plant species
Authors: VAN OORSCHOT J. L. P. , VAN LEEUWEN P. H.
Published: July 2006

Inhibition of photosynthesis by metamitron in the rooting medium and its subsequent recovery after transfer of the roots to herbicide‐free nutrient solution was measured in eight plant species.

Fast and complete recovery within a few hours after treatment showed that metamitron, once absorbed, was rapidly and completely inactivated in the leaves of sugar beet (Beta vulgaris L.). Inactivation in perennial ryegrass (Lolium perenne L.) was slower and incomplete. It was low in Echinochloa crusgalli (L.) P.B., Amaranthus retroflexus L., Alopecurus myosuroides Huds. and bean (Phaseolus vulgaris L.), and undetectable in maize (Zea mays L.) and Portulaca oleracea L.

From the transpiration rate and the concentration of metamitron in the nutrient solution that just did not cause inhibition of photosynthesis in sugar beet, uptake and inactivation rates per unit leaf area were calculated to be at least 18·5 ng/cm2/h. The same external concentration markedly depressed photosynthesis in the other more susceptible species.

After leaf sprays sugar beet plants gradually resumed the normal rate of photosynthesis, but bean plants did not recover.
Translocation of 2,4‐D, asulam and amitrole in water hyacinth
Authors: SINGH S.P. , MÜLLER F.
Published: July 2006

In glasshouse experiments foliar application or 14C‐labelled herbicides to water hyacinth plants at the 4‐leaf stage indicated that amilroie transport from the treated leaf blade was faster and greater than 2.4‐D. but a little less than asulam. From the treated leaf 14·2, 25·9. 39·7. 44·5 and 51·8% of the recovered 14CNamitrole was translocated at intervals of 6 h. and 1. 3. 6 and 12 day., respectively. Both xylem and phloem transport of asulam and amitrole was evident, whereas 2.4‐D moved only from ‘source to sink’.

Movement of the herbicides from the mother to the connected daughter plant or vice versa was dependent upon the size of the latter. Maximum transport of these herbicides in either direction took place at the 2‐leaf stage of daughter plants. With any increase or decrease in the number of leaves on daughter plants, the transport of herbicides was reduced. As an exception, daughter plant to mother plant movement of amilroie was maximum at the 1‐leaf stage.

After extraction, fractionation and TLC separation of foliage applied 14C‐2.4‐D 76–4 and 72·1% of the radioactivity was detected in the chloroform phase of the leaf extract at 3 and 6 day intervals, respectively.

In another pot culture experiment, it was observed that after spraying the mother plants with 2.4‐D‐amine at 0–75 kg/ha the connected daughter plants at 1 to 4‐leaf stages werckilled if the culture solution was contaminated while spraying, or by dying leaves. When contamination was totally avoided, the connected but unsprayed daughter plants at 3 to 4‐feaf stages survived.
Herbicide tank‐mixing for post‐emergence weed control in sugar beets
Authors: GIANNOPOLITIS C. N. , STROUTHOPOULOS TH. G.
Published: July 2006

Tank‐mixtures of selective herbicides were evaluated for 2 years on field‐grown sugarbeets under two weed flora situations: (a) mixed floras of broad‐leaved and grass weeds and (b) weed floras of broadleaves grown beyond their stages of greatest sensitivity to herbicides. In these situations single herbicides usually fail to provide satisfactory post‐emergence weed control in sugarbeets.

Of several tank‐mixtures, which could be devised for use in the first situation, ethofurnesate + Betanal AM 11, diclofop‐methyl + Betanal AM 11 and diclofop‐methyl + metamitron gave synergistic phytotoxicity to sugarbeet seedlings. Synergism in weed control, becoming apparent by an accelerated appearance of the herbicidal effects, was obtained with the mixture alloxydimeton + Betanal AM 11. This mixture was not phytotoxic and appears to be the most efficient for simultaneous control of broad‐leaved and grass weeds.

From trials in the second situation it became apparent that the activity of metamitron, which was reduced on older weeds, could be restored by mixing with a non‐phytotoxic oil or a low dose of Betanal AM 11. These mixtures should be useful when growth of sugarbeets has been retarded by carried‐over herbicides, drought, frost, etc.
Differences intraspecifiques chez Convolvulus arvensis L.*
Authors: GARCIA‐BAUDIN J. M. , DARMENCY H.
Published: July 2006

Divers aspects de la biologie du liseron sont abordés dans ce travail à travers l'étude comparative de populations d'origine française et espagnole. Le poids des semences, la caryologie, les résultats del'électrophorése des protéines séminales solubles, la morphologic foliaire et l'aptitude à la floraison, ont été les caractères utilisés. L'observation des plantes cultivées ensemble à Madrid et la comparaison des électrophorégrammes ont permis de proposer un schéma de différenciation intraspécifique chez Convolvulus arvensis L., en se fondant principalement sur l'influence de sa répartition géographique, facteur rendant bien compte des variations enregistrées. Ce phénomène introduit un élément supplémentaire de variation pouvant affecter la réussite des traitements herbicides.
The influence of herbicides, nitrogen fertilizer, seed rate and method of sowing, on the establishment and long‐term composition of a perennial ryegrass ley.
Authors: AGGAR R. J. H
Published: July 2006

Changes in ihe species composition of a ryegrass pasture were examined over a 2 year period from a spring establishment. Seed of S23 perennial ryegrass was sown in main plots, eilher broadcast or drilled, at rates of 15, 25 or 35 kg/ha in a field experiment at Oxford. The whole area was oversown withfour weed grasses (Agrostis siolonifera.Holcus lanatus. Poa annua and P trivialis). Five cultural and three herbicide treatments were applied across the plots. These consisted of three levels of nitrogen (0. 50 and 100 kg N per ha), two companion species (Italian ryegrass and white clover) and 2.4‐D, benazolin and methabenzihiazuron applications.

Ten weeks after sowing, broad‐leaved weeds accounted for nearly half the lotal dry‐matter yield, except where controlled by the three herbicides. Grass yields were nol increased by herbicide treatment. The only cultural treatment checking broad‐leaved weeds was ihe 35 kg/ha seeding rale.

Seven months after sowing, the only treatment which had decreased the abundance of weed grasses was melhabenzthiazuron especially againsi A. stolonifera and Poa spp. Two years afler sowing, perennial ryegrass had only 34% ground cover and had been replaced largely by H. lanatus (38%), Poa spp, (15%) and A. stolonifera (7%), Where methabenzthiazuron had been used the ryegrass ground cover was 48%. with less P. trivialis and A. stolonifera. but H. lanatus was nol altered. White clover decreased H. lanatus cover.

In two supplementary pot experiments, methabenzthiazuron sprayed pre‐emergence damaged perennial ryegrass unless the seed was covered with at least 4 mm of soil. Only H. lanatmand F. rubra out of sixteen grasses were relatively resistant to methabenzihiazuron when applied at ihe tillering stage, confirming that this herbicide has potential for preventing the ingress of many unsown grasses in new leys.
Persistence of dichlobenil in a sandy soil and effects of residues on plant growth
Authors: WILLIAMS JOHN H. , EAGLE DAVID J.
Published: July 2006

The persistence of dichlobenil following the application of dichlobenil granules was studied in a replicated plot experiment including both surface and incorporated treatments of 8·3 and 16·6 kg/ha ai. Soil analyses showed an initial half‐life of about 4 weeks but the persistence increased with time and a year after application the half‐life was about 1 year. Incorporation of the granules into the soil markedly increased the persistence of dichlobenil and its metabolite dichlorobenzamide. The most sensitive crop was carrot which was damaged by residues of only 1–2% of the recommended dose. Residues phytotoxic to carrots persisted for 2 years from the 8·3 kg/ha surface application and 5 years from the 18·6 kg/ha incorporated application. Lettuce was also highly sensitive to residues.
Factors affecting glyphosate activity in Imperata cylindrica (L.) Beauv. and Cyperus rotundus L. II: effect of shade
Authors: MOOSAVI‐NIA H. , DORE J.
Published: July 2006

Imperata cylindrica and Cyperus rotundus were grown under three different light regimes; unshaded, 50% shade, and 75% shade and no shade plus 75% shade before and after spraying, (temporary shade) in a heated greenhouse. Six weeks after the start of the experimenis, glyphosate was applied to the plants at 0·2, 0·4 and 0·8 kg/ha (for Imperata) or 0·3, 0·6 and 1·2 kg/ha (for Cyperus). Glyphosate toxicity was enhanced as shade increased. In Imperata, all shade regimes at all rates of glyphosate eaused greater damage to the plants than the unshaded regime. The reduction in shoot dry weight, rhizome dry weight and total carbohydrate content of Imperate rhizotties at 75% continuous and temporary shaiie conditions, with the lowest rate of glyphosate, was almost twice as much as the reduction in the same features m the unshaded plants caused by the highest rate of glyphosate. In Cyperus. glyphosate at the intermediate and highest rates decreased the shoot dry weight at 75% continuous shade by 79% and 98% respectively. Plants in 50% shade were significantly affected only at the highest rate of glyphosate. Sprouting ability of the tubers al 75% continuous shade was inhibited when the tubers were replanted for recovery. Enhanced toxicity of glyphosate in reduced light intensity was attributed to the morphological changes in the nature of the leaves caused by shade.
Determination of extractable and non‐extractable radioactivity from prairie soils treated with carboxyl‐ and ring‐labelled [14C]2,4‐D
Authors: SMITH ALLAN E. , MUIR DEREK C. G.
Published: July 2006

Ring‐ and carboxyl‐labelled [14C]2,4‐D were incubated under laboratory conditions, at the 2 g/g level, in a heavy clay, sandy loam, and clay loam at 85% of field capacity and 20 1C. The soils were extracted at regular intervals for 35 days with aqaeous acidic acetonitrile, and analysed for [14C]2,4‐D and possible radioactive degradation products. Following solvent extraction, a portion of the soil residues were combusted in oxygen to determine unextracted radioactivity as [14C]carbon dioxide. The remaining soil residues were then treated with aqueous sodium hydroxide, and the radioactivity associated with the fulvic and humic soil components determined.

In all soils there was a rapid decrease in the amounts of extractable radioacitivity, with only 5% of that applied being recoverable after 35 days. All recoverable radioactivity was attributable to [14C]2,4‐D, and no [14C]‐containing degradation products were observed. This loss of extractable radioactivity was accompanied by an increase in non‐extractable radioactivity. Approximately 15% of the applied radioactivity, derived from carboxyl‐labelled [14C]2,4‐D, and 30% from the ring‐labelled [14C]2,4‐D was associated with the soil in a non‐extractable form, after 35 days of incubation.

After 35 days, less than 5% of the radioactivity from the carboxyl‐labelled herbicide, and less than 10% of the ringlabelled material, was associated with the fulvic components derived from the three soils. Less than 5% of the applied radioactivities were identifiable with any of the humic acid components.

It was considered that during the incubation [14C]2,4‐D did not become bound or conjugated to soil components, and that non‐extractable radioactivity associated with the three soil types resulted from incorporation of radioactive degradation products, such as [14C]carbon dioxide, into soil organic matter.
The effect of CGA 43089 as a safener of metolachlor in sorghum (Sorghum bicolor) (Recordings of elongation rates on single sorghum leaves)
Authors: CHRIST R.A.
Published: July 2006

The influence of metolachlor [2‐chloro‐6‐ethyl‐N‐(2‐methoxyl‐methylethyl)acet‐o‐toluidide] on sorghum (Sorghum bicolor Moench.) is first demonstrated in order to be able to show the difference observed when this herbicide is applied together with CGA 43089. The effect of various concentrations (in nutrient solution) and of various exposure times on the elongation rate of single leaves is demonstrated.

The safener CGA 43089 (x‐(cyanomethoximino)‐benzacetonitrile] showed no effect on the elongation rates when used in normal concentrations. The combined application of safener and metolachlor (concentration ratio 1:3) prevented the growth reductions due to metolachlor. When the safener was applied before metolachlor the safening action was as good as that of the combined application. When the safener was applied 1 or 2 days after the herbicide the safening effect was diminished. Plant uptake of the safener over a period of 3 days was sufficient to prevent the action of metolachlor but the safening effect was reduced when the interval between the end of safener application and the beginning of the herbicide application was increased. The conclusion drawn regarding the mode of action is that CGA 43089 does not interfere with herbicide uptake into the plant. The safener is, however, able to reduce the active amount of herbicide when present at the right time at the site of effect.
The influence of atomizer, pressure and formulation on the droplet spectra produced by high‐volume sprayers
Authors: COMBELLACK J.H. , MATTHEWS G.A.
Published: July 2006

Techniques of high‐volume spraying of weedy plants, have not changed greatly since their introduction in the late 19th century. improvements to the effieiency of the operation have been investigated, and the influence of atomizer type. pressure and formulation on the droplet spectra produced were assessed. The VMD (volume median diameter) decreased log linearly (r2 > 0.98 with all atomizers tested. whilst the volume of the small‐droplet component (< 107 μm) increased linearly (r2) with increasing pressure. A comparison of the droplet spectra produced by three fan and three swirl cone atomizers showed that the fan atomizers gave significantly higher VMD's and lower volumes of small droplets than cone atomizers under comparable operating conditions. The influence of type and concentration of’formulation on the droplet spectra was variable with both the fan and cone atomizers The atomizer and pressure had the greater influence on the droplet spectra. but the effects of formulalion must also be considered if improvements are to be obtained in high‐volume spraying
Soil persistence and distribution of ethofumesate applied to autumn‐sown perennial ryegrass for Poa annua control
Authors: HAGGAR R.J. , PASSMAN A.
Published: July 2006

A bioassay technique based on Poa annua growth showed that ethofumesate applied at 2.0 kg/ha in October to a newly‐sown ryegrass (Lolium perenne) sward had a half‐life of just over 8 weeks. After 7 months there was still sufficient herbicide present to cause about a 50% reduction in P. annua growth. The movement of ethofumesate, as measured in soil cores taken 15 months after spraying, was confined mainly to the upper 2 cm of the soil profile. Seeds on the soil surface at spraying were very sensitive to ethofumesate. The implications of the findings for weed control in newly‐sown grass leys are discussed.
In situ potential for rehabilitation of sites dominated by blackberry (Rubus polyanthemos Lindeb.)
Authors: PANETTA F. D.
Published: July 2006

Soil samples were taken along transects cut through thickets of Rubus polyanthemos at three sites, the seeds were extracted by flotation, and the viability of filled seeds of R. polyanthemos determined by staining with tetrazolium chloride. Exotic annual species were the dominant component of the soil flora at two sites formerly undercultivation and a change in seed bank composition, both in number of individuals and numberof species, was evident from the exterior to the interior of the thickets. This was not observed in a relatively undisturbed native community. The apparent absence of suitable replacement species in the seed bank at all three sites means that they must be introduced if the sites are to be rehabilitated after the thickets are removed. Viable seeds of R. polyanthemos were present in relatively low numbers (mean 179 m−2:), so that loss of viability appears to be fairly rapid.
Effect of glyphosate on the sprouting of Cyperus rotundus L. tubers
Authors: DOLL J.D. , PIEDRAHITA W.
Published: July 2006

Post‐emergence applications of glyphosate [N‐(phosphonomethyl)glycine] have been shown not to eradicate purple nutsedge (Cyperus rotundus L.) in the field. It was not known if this was due to failure to control emerged plants or if dormant tubers produced new plants after application. Studies with individual plants were conducted in screenhouse facilities to determine the effects of glyphosate rate, time for translocation, area of foliage treated, and shade on the sprouting ability of tubers attached to treated plants. Rates of 1.5–2.0 kg/ha glyphosate inhibited tuber sprouting; 72 h were required for complete translocation at 1.0 kg/ha whereas 36 h were sufficient at 2.0 kg/ha. Treating less than all of the foliage reduced foliar control and increased tuber sprouting. Shading treated plants reduced control of the foliage but did not affect glyphosate translocation to the tubers. These studies showed that glyphosate kills C. rotundus foliage and the tubers attached to treated plants. Therefore, regrowth after glyphosate application under field conditions is due to dormant tubers which sprout after treatment.
A survey of grass weeds in cereals in central southern England
Authors: FROUD‐WILLIAMS R.J. , CHANCELLOR R.J.
Published: July 2006

A survey of grass weeds in cereals in nine areas of central southern England was made in summer 1981 with the primary purpose of determining the importance of Bromus sterilis. A total of 1477 fields of winter wheat, 715 of winter barley and 434 of spring barley were assessed by visually scoring the whole field for grass flower heads. In all, 19 species were found; their levels of infestation were scored. In winter cereals the most frequent species were Avena spp. in 32% of fields. Agropyron repens in 24%, Poa trivialis in 22% and Alopecurus myosuroides in 19%. Bromas sterilis was next most frequent in 9%. In spring barley the two most frequent species were Agropyron repens in 53% of the fields and Avena spp. in 52%. The third most frequent was Alopecurus myosuroides in 1 1%.

Bromus sterilis was recorded in 12% of winter wheat and 4% of winter barley crops, but did not occur in spring barley. Of the 206 fields where it was present it occurred throughout the field in only 82 and it was confined to the headlands in the remainder.
Effect of simulated mowing on the translocation of mefluidide in perennial ryegrass (Lolium perenne L.)
Authors: FIELD ROGER J. , WHITFORD A. R.
Published: July 2006

Young plants of perennial ryegrass (Lolium perenne L.) absorbed approximately 50% of an application of the grass growth retardant, mefluidide, while from 6.5 to 21.9% of the applied dose was translocated during a 2‐ or 7‐day period respectively. After the 2‐day period 93.4% of extractable radioactivity was identified as mefluidide. This potentially useful chemical was made unavailable as a result of mowing before or after spraying. Mowing before spraying increased the proportion of cut mature laminae and young laminae, neither of which translocated mefluidide to other plant organs as efficiently as intact, mature leaves. Mowing after spraying removed potentially translocatable mefluidide with the cut mature laminae and reduced mefluidide accumulation in untreated plant parts. While mowing treatments may be aesthetically desirable they probably increase the amount of mefluidide necessary for effective growth retardation.
The dormancy of wild oat seed (Avena fatua L.) from plants grown under various temperature and soil moisture conditions
Authors: PETERS N. C. B.
Published: July 2006

Wild oat plants of types fA, fB and fC were grown at a constant 15 or 20°C during the period of seed maturation. Seed of the three types differed little in dormancy when grown at 15°C, but at 20°C a larger proportion of seeds of type fA were dormant compared with fB or fC. Overall, dormancy of seed produced at 15 and 20°C was 97 and 63% respectively. Plants of another collection of type fB were grown from seed at 15 or 20°C with or without water stress applied only from the time of panicle emergence. Water stress and high temperature reduced viable seed production. Seed dormancy was tested immediately after collection by planting the seed in soil, and by Petri dish tests. Further Petri dish tests were made after 6 months storage. Seedling emergence in the first autumn from seeds of plants matured without water stress at 15°C was 10% compared with 30% for seeds grown at 20°C. Seeds grown with water stress at 15°C gave 47%, and at 20°C 78% emergence. The majority of emergence from seeds formed at 15°C without water stress occurred in the second spring after burial. Petri dish tests support these findings and suggest that seeds produced in hot dry summers are less dormant than those produced in cool moist ones.