bluuebunny/crossref_metadata_2025_split huggingface dataset:
The influence of tillage on the weed flora in a succession of winter wheat crops on a clay loam soil and a silt loam soil
Authors: POLLARD F. , MOSS S.R. , CUSSANS G.W. , FROUD‐WILLIAMS R.J. 
Published: July 2006

SummaryWeed populations were monitored for 4 years on two experiments designed to compare the effect of different primary tillage treatments on winter wheat (Triticum aestivum L.) cropping. Ploughing was compared with deep and shallow tine cultivation and with no tillage on both a clay loam and a silt loam over chalk. Soil‐acting residual herbicides were used to control weeds, especially Alopecurus myosuroides Huds. and Avena fatua L.Dicotyledonous weeds were uncommon on the clay loam but on the silt loam, in a year when no residual herbicide was used, they were most numerous where the soil was disturbed most. In other years there was little difference in the number emerging. Six species were reduced in number by reduced cultivation or no tillage, whilst four species, including two grasses, were increased.At both sites, A. myosuroides was more numerous on direct drilled and tine cultivated plots than on ploughed. Herbicides gave good control on the silt loam but failed to control the weed on the clay loam. On the clay loam, A. fatua was most numerous on tine cultivated plots and a combination of herbicides and roguing produced a decline in the population.
Comportement de substances analogues du propyzamide dans la plante en fonction de leur structure chimique
Authors: ASPE D. , BASTIDE J. 
Published: July 2006

RésuméL'absorption, la métabolisation et la migration dans la plante d'orge d'analogues du propyzamide sont étudiées. Sur une plantule développée, l'absorption est parallèle à la pénétration d'eau. alors que pendant la germination, l'absorption est proportionnelle au paramètre hydrophobique π.Il n'y a pas de différence de migration entre chacun des produits, par contre il y a une différence de métabolisation et le taux de métabolisation est directement lié au paramètre électronique π. Cependant ces variations ne reflètent pas les différences observées sur l'activité biologique globale qui est reliée au paramètre hydrophobique π et au facteur stérique Es.
The uptake of soil‐applied chlorotriazines by seedlings and its prediction
Authors: ROBINSON R. C. , DUNHAM R. J. 
Published: July 2006

Summary 14C‐labelled atrazine or terbuthylazine was applied to the surface of soil columns 100 mm deep and the uptake by oat seedlings measured for up to 24 days after germination following two contrasting rainfall treatments. Attempts were made to predict measured uptake on the basis of mass flow theory given also measurements of transpiration rates, water, rooting and herbicide distribution profiles in the soil, and soil adsorption characteristics. Predictions over a tenfold range of uptake were close enough to suggest that the assumptions made to predict mass flow uptake were essentially correct. Discrepancies appeared to result principally from (i) shoot‐zone uptake, and (ii) incorrect prediction of long‐term herbicide adsorption in undisturbed soil. Greater attention to the effect of herbicide on transpiration rates and to the patterns of water uptake by roots should improve the accuracy of such predictions. The various factors that influence the mass flow uptake of chlorotriazines in the soil surface by seedlings are discussed as a basis for modelling herbicide uptake.
Etude du polymorphisme des prolamines chez une population d'Avena fatua L.
Authors: DARMENCY H. 
Published: July 2006

Résumél'étude par l'électrophorèse du polymorphisme des prolamines (protéines alcoolo‐solubles du grain) a permis de mettre en évidence des modifications de la structure phénotypique d'une population d'Avena fatua L. au cours de trois années successives. Des corrélations avec les facteurs climatiques et culturaux ont été faites, ce qui a conduit l'auteur à proposer des hypothèses sur les mecanismes d'évolution. Ainsi, le caractère de floraison tardive et de vernalisation est étroitement corréléà l'un des quatre phenotypes principaux de la population, et un autre phénotype présente une sensibilité accrue à certains herbicides des céréales. Ces phénomènes entraineraient le maintien d'un polymorphisme non négligeable. L'analyse des prolamines permet donc de reconnaître des plantes qui ont des comportements écologiques différents, et de prévoir l'évolution des populations d'A. fatua vers des types plus ou moins nuisibles.
The contact activity of difenzoquat in two United Kingdom spring wheat cultivars
Authors: PALLETT K. E. 
Published: July 2006

SummaryThe contact action of difenzoquat was investigated on seedlings of spring wheat (Triticum aestivum L.) cultivars tolerant (Maris Butler) and susceptible (Sicco) to the translocated etTect of the herbicide on the apical meristem. Applied as a spray the chemical caused an increase in electrolyte leakage before the development of visible damage. Chlorophyll levels were also reduced and both effects were greater on Maris Butler than Sicco.Droplets of difenzoquat caused similar ultrastructural effects on the two cultivars. These included swelling of the chloroplasts with subsequent disorganization of the thylakoid system accompanied by disruption of other cellular components. Similar effects have been reported with paraquat and it is suggested that the contact action of difenzoquat is due to a weak paraquat type activity.
Integrated pest management techniques in thistle suppression in pastures of North America
Authors: TRUMBLE J.T. , KOK L.T. 
Published: July 2006

SummaryThistles in the genera Carduus, Cirsium, Onopordum, and Silybum of the subtribe Carduinae have been the subjects of considerable research designed for chemical, biological, cultural, and integrated control in the United States. Problems and costs associated with chemical and cultural control techniques stimulated the introduction of biological control agents from many locations in Europe and the Middle East. Although some natural enemies have successfully suppressed thistle infestations, economic losses during the time lags between introduction and effective suppression prompted investigations into integrated control procedures. The rationale, history, and potential direction for thistle suppression has been documented in this manuscript.
Germination of Setaria chevalieri caryopses
Authors: ERASMUS D.J. , VANSTADEN J. 
Published: July 2006

SummaryGermination studies were made on Setaria chevalieri caryopses (seeds). The seeds imbibed readily upon moist incubation. An after‐ripening period which followed a cyclic patlern was necessary for maximum germination. Freshly harvested seed germinated in the presence of light, but only very sporadically in the dark. The germination of dark incubated seed was improved if the seeds were subsequently exposed to light. This photodormancy became less pronounced with dry storage. Treatment with red light increased germination. but was reversed by far‐red light suggesting that a phytochrome system operates in the seeds. Sodium azide treatments did not stimulate germination in the dark but were effective in the presence of light.
Some studies on the competition between Avenu fatua L. and spring barley.II. Variation of A. fatua emergence and development and its influence on crop yield.
Authors: PETERS N.C.B. , WILSON ARC B.J. 
Published: July 2006

SummaryThe emergence and development of A fatua were studied in 23 spring barly fields in 1972 and nine in 1973 nautarally infested with yhe weed. Emergence occurred up to the four‐leaf stages of the crop. The mean number of days from drilling to 50% emergence of A fatua plants was 22 in 1972 and 36 in 1973.The majority of seeds were shed by early emerging plants in 1972, 79% and in 1973. 59% of A fatua plants had emerged by the two‐leaf stage of the crop and these plants produced 97 and 89% respectively of all the seed shed. In both years, A fatua plants emerging before the crop produced five times as many seeds per plant as those emerging between the crop two and three‐leaf stages. The earliest emerging plants were also the heaviest and had most stems per plant.In both years there was a significant relationship between the density of A fatua plants in the crop in spring and their mortality.A large variation occured between the sites in the number of A fatua plants that emerged by a given crop leaf stage. In 1973.insufficient numbers of sites were investigatesd to derive a relationship between time to A fatua emergence and crop yield loss, but in 1972, a given density of A fatua plants emerging at an early stage caused agreater crop yields loss than the same density emerging later. This was also evident to aleser extent in data derived from a similar series of 15 experiments in 1971.
Effet des matières organiques ajoutées au sol sur l'adsorption des herbicides. Influence de la composition des matières organiques
Authors: GAILLARDON P. , GAUDRY J.C. , CALVET R. 
Published: July 2006

RésuméEn fractionnant préalablement deux substrats organiques (une paille de blé et im fpom de luzerne broyés) nous avons tenté d'évaluer le pouvoir adsorbant, dans le sol, de leurs composants (substances hydrosolubles et lipidiques, héicelluloses, cellulose et lignine). La terbutryne et le diuron n'ont pas la méme affinité pour les composants des substrats. La lignine est plus adsorbante que les autres composants. Auregard de l'adsorption, les composants isolés constituent des classes hétérogènes et interagissent. Par suite il apparait difficile de décrore le pouvoir adsorbant des matières organiques non décomposées à partir de leur composition. La minéralisation, en modifiant la composition des substrats pourrait expliquer au moins partiellement les variations du pouvoir adsorbant des résidus carbones provenant de la décomposition des substrats dans le sol.
Influence of light, temperature and humidity on the translocation and activity of glyphosate in Elymus repens (=Agropyron repens)
Authors: COUPLAND D. 
Published: July 2006

SummaryThe effects of light, température and humidity on the performance and translocation of glyphosate in Elymus repens (L.) Gould (=Agropyron repens L. (Beauv.)), during the period of 48 h after treatment, were studied in controlled‐environment cabinets. Increases in the levels of all three factors resulted in increases in herbicide performance. In general, these differences were statistically significant at all treatment periods except the longest when almost full control was achieved. The results highlight the important influence of environmental factors on herbicide performance during the short‐term, post‐spraying period. The application of 14C‐labelled glyphosate to the adaxial leaf‐sheath surface resulted in very rapid uptake and was used as a method of treating plants to study herbicide translocation under different environmental conditions. Increased light levels and temperatures enhanced basipetal translocation to the crowns and rhizomes but increased humidity had no significant effect with this form of application.
Growth of Elymus repens (L.) Gould and Agrostis gigantea Roth. at different light intensities
Authors: SKUTERUD ROLF 
Published: July 2006

Summary Elymus repens (L.) Gould and Agrostis gigantea Roth. raised from rhizomes both responded to reduced light intensity by increased stem length, while the number of aerial shoots was reduced. The weight of the aerial parts was not influenced by a 50% reduction of the daylight intensity, but a further reduction of light caused a significant decrease in weight. The production of new rhizomes was more influenced by shading than were the aerial shoots. The consequence was an increase in the shoot/rhizome ratio.The food reserve per bud measured as inter‐node weight in E. repens and A. gigantea was reduced only with intensive shading, and the vitality of the rhizomes appeared independent of light intensity.Intensive shading in early as compared to late summer caused a reduction in the number and weight of aerial shoots, but not in the weight of new rhizomes. Light intensities equal to those found in a spring wheat crop allowed more E. repens growth than light intensities equal to those in a spring oat crop. E. repens raised from seeds and grown at light intensities equal to those found in a cereal crop, showed insignificant rhizome production.
Selectivity factors relative to asulam for Senecio jacobaea L. control in Medicago sativa L. I. Retention, uptake and translocation*
Authors: HARPER DELBERT R. , APPLEBY ARNOLD P. 
Published: July 2006

Summary Senecio jacobaea L. and Medicago sativa L. plants grown in a glasshouse were treated with foliar applications of aqueous solutions of asulam. Retention on foliage, uptake and translocation were measured in both species. Retention was greater in S. jacobaea than in M. sativa when no surfactant was added and similar when surfactant was added. Addition of surfactant modified spray distribution and increased asulam uptake in M. saliva but did not in S. jacobaea. S. jacobaea translocated over twice as much asulam from the treated area as M. sativa. These data suggest that surfactant should not be added for maximum selectivity. Differences in species response to asulam treatments are partially, but not entirely, explained by differences in retention, uptake and translocation.
Effects of application method on the performance of some soil‐applied herbicides II. Field studies
Authors: ADDALA M. S. A. , HANCE R. J. , DRENNAN D. S. H. 
Published: July 2006

SummaryPlots sown with a range of test species were treated with chlortoluron, nitrofen, propyzamide or terbutryne applied at several doses either by rotary atomizer (30 1 ha−1), conventional hydraulic nozzle (250 1 ha−1) or dribble bar (with orifices spaced at 2‐cm intervals) (520 1 ha−1). The performance of chlortoluron, propyzamide and terbutryne was similar with all the methods used, regardless of soil and weather conditions. Vertical movement in the soil was similar for each application method. Horizontal variability following dribble‐bar application was measured for chlortoluron and was very large across short distances but weed control was as uniform as with the other application methods.In a further experiment, the phytotoxicity of chlortoluron applied by each of the three methods was less in a seed bed prepared by minimum tillage following straw burning than in a ploughed and cultivated seed bed. Activity following minimum tillage and straw baling was intermediate. This difference in phytotoxicity probably resulted from greater adsorption in the surface layers of the minimal cultivation treatments.
Les définitions d' ‘adventicee’ et de ‘mauvaise herbee’
Authors: GODINHO ISABEL 
Published: July 2006

RásumáLes définitions d' ‘adventicee’ et de ‘mauvaise herbee’ en Français, de ‘weede’ en Anglais et de ‘Unkraute’ en Allemand ont été relevées dans la bibliographie. La difficulté de trouver une seule définition satisfaisante pour ‘weede’ et ‘Unkraute’ est insurmontable puisque ces mots ont deux sens et doivent par conséquent avoir deux définitions distinctes: (i) adventice, weed, Unkraut (sens écologique): plante qui croit spontanément dans les milieux modifiés par l'homme; (ii) mauvaise herbe ou malherbe, weed, Unkraut (sens malherbologique): plante indésirable.
Seed survival and periodicity of seedling emergence in four weedy species of Papaver
Authors: ROBERTS H. A. , BODDRELL JUNE E. 
Published: July 2006

SummarySeeds of Papaver argernone, P. dubium, P. lecoqii and P. rhoeas were collected in each of three or four years and mixed with the top 7·5 cm of sterilized soil confined in cylinders sunk in the ground outdoors and cultivated three times yearly. Except for P. argemone, no more than 6% of seeds produced seedlings in the autumn of sowing; seedling numbers were usually greatest in the following year and then decreased exponentially from year to year. Mean survival of viable seeds after 5 years ranged from 7·4% for P. lecoqii to 2·0% for P. argemone. Most seedlings of all four species emerged in early spring and early autumn; emergence of P. rhoeas was greater in spring than in autumn, but the reverse was true for the other three species.
Herbicides for injection into flowing water: acrolein and endothal‐amine
Authors: BOWMER KATHLEEN H. , SMITH G. H. 
Published: July 2006

SummaryTreatment of flowing water by injection with acrolein is widely used in Australia and elsewhere for control of submerged aquatic plants. However, since acrolein has several disadvantages the amine salt of endothal has been assessed as an alternative for control of Elodea canadensis Rich., the most important species in blocking irrigation flow in south‐eastern Australia. Using an exposure time of 3 h in a static assay in the field the standard treatment with acrolein, nominally 15 ppm, was far more effective than endothal at about 5 ppm, similar results being obtained in spring, mid‐ and late summer. In a test over a range of concentrations in mid‐summer, acrolein gave 80% reduction of biomass at 2·8 ppm but endothal did not give this level of control even when more than 100 ppm was used. Endothal was also relatively ineffective when injected into flowing water.Measurements of net photosynthesis and lethality suggest that the order of tolerance to acrolein is Potamogeton tricarinatus F. Muell & A. Benn., > E. canadensis ≥ Vallisneria gigantea Graebner, so that routine treatments with acrolein may contribute directly to changes in relative species dominance. Use of sublethal concentrations of acrolein stimulated the growth of E. canadensis relative to untreated controls, perhaps by reducing the competition of aufwuchs.
A simple bioassay for photosystem‐II inhibitors in water using in vivo chlorophyll fluorescence*
Authors: GOLDSBOROUGH L. G. , ROBINSON G. G. C. 
Published: July 2006

SummaryA simple bioassay is described in which the increase of in vivo chlorophyll fluorescence of unialgal continuous, cultures is related to the concentration of photosynthetic inhibitors by a hyperbolic function. Concentrations of the herbicide terbutryne detected by the bioassay in an aquarium microcosm were generally within 2 μg 1−1 of estimates by gas chromatography. A multispecies bioassay approach is proposed, which combines high sensitivity with a wide operating range of concentrations.
Contribution à l'étude de la biologie de Solanum elaeagnifolium Cav. (Solanacées), adventice des cultures dans le périmètre irrigué du Tadla (Maroc)
Authors: TANJI A. , BOULET C. , HAMMOUMI M. 
Published: July 2006

Résumé Solanum elaeagnifolium Cav. infeste actuellement 100 000 ha de cultures irriguées dans le périmètre du Tadla (Maroc Central). Sa forte capacité de reproduction végétative est liée d'une part à l'intensité des facons culturales et d'autre part, à son type biologique géophyte. Par ailleurs, elle se reproduit également bien par la voie sexuée: les graines produites en grand nombre germent dès le mois de Février date à laquelle les rejets apparaissent ce qui ne fait qu'accentuer son agressivité. Au Maroc, l'espèce fleurit en Mai et fructifie dès le mois de Juillet, l'hiver correspondant au repos végétatif. En conséquence, sa nuisibilité est généralisée et elle est plus particulièrement forte dans toutes les cultures de printemps (coton, maïs, sésame, etc.).
Actions of sodium hypochlorite and hydrogen peroxide on seed dormancy and germination of wild oats, Avena fatua L.
Authors: HSIAO ANDREW I. , QUICK WILLIAM A. 
Published: July 2006

SummarySodium hypochlorite (NaOCl) can release dormancy of imbibed wild oat (Avena fatua L.) seeds. Treatments found effective included (i) immersing intact seeds in 800 mm NaOCl for 1 h followed by incubation on 5 × 10−4m gibberellin A3(GA3); (ii) immersing dehulled seeds in 800 mm NaOCl for 1 min followed by incubation on 5 × 10−4m GA3; (iii) immersion of dehulled seeds in much lower concentrations of NaOCl, e.g. 13 4 mm for 3 h followed by incubation on water; or (iv) incubating dehulled seeds on a low concentration of NaOCl. Based on the concentrations of each of the reagents required to produce equivalent responses, NaOCl is approximately 4–6 times more effective than hydrogen peroxide (H2O2) in triggering the onset of germination, and 6 times as effective in causing growth inhibition in the roots. These results suggest the modes of action of NaOCl and H2O2 in the termination of dormancy reside in a modification of the properties of the hull and seed coat membranes, and in the provision of additional oxygen to the seed.
Weed interference in maize, cowpea and maize/cowpea intercrop in a subhumid tropical environment. II. Early growth and nutrient content of crops and weeds
Authors: AYENI A. O. , AKOBUNDU I. O. , DUKE W. B. 
Published: July 2006

Summary:Early growth and nutrient content of crops and weeds from weed‐free and weedy no‐tillage maize (Zea mays L, cv. TZB), cowpea (Vigna unguiculata (L) Walp. cv. VITA‐5) and maize/cowpea intercrop at populations of 40000, 50000 and 30000 + 40000 plants ha−1 grown on a loamysand Oxic Ustropept in a subhumid tropical location were monitored in the early and late 1979 cropping seasons. In the first 6 weeks of growth in the early season, cropping pattern had no effect on weed growth; weeds did not suppress crop growth significantly until 5–6 weeks after sowing and total crop dry weights were not affected by cropping pattern. Three weeks after sowing, weeds from weedy crop plots had taken up two to four times as much nutrient (N, P, K, Ca + Mg) as was taken up by corresponding weed‐free crops. In the late season, weed dry weight 6 weeks after sowing was depressed in the intercrop compared to monocultures and dry‐matter production of the intercrop was higher than those of monocultures. The resource use index (RUI), defined as the amount of an environmental resource used by a weed‐free crop divided by the combined amount of the same resource used by the corresponding weedy crop and the associated weeds, increased with age of crop and was higher for the intercrop than the monocultures only in the late season.
Evaluation du stock en semences de la morelle jaune (Solanum elaeagnifolium Cav.) dans le sol du Tadla (Maroc)
Authors: BOUHACHE M. , TANJI A. 
Published: July 2006

RásumáA partir des échantillons de sol, prélevés dans quatre champs du périmètre irrigué du Tadla (Maroc Central) et choisis dans la zone la plus infestée par Solanum elaeagnifolium, des estimations de semences de cette adventice vivace, révèlent que la valeur moyenne du stock en semences dénombrées (semences mortes + semences viables) de S. elaeagnifolium est de 375 semences au m2 sur 60 cm de profondeur. Tandis que la valeur moyenne du stock en semences viables est de 163 semences au m2 sur 60 cm de profondeur, ceci représente en moyenne 43, 5% du stock total en semences dénombrées.Le profil moyen de répartition des semences de S. elaeagnifolium dans le sol est le suivant: 71,7, 25,1 et 3,2% respectivement, dans les horizons 0–20, 20–40 et 40–60 cm. De même, la répartition verticale des semences viables suit le même profil que le stock total, ainsi nous trouvons que 73 et 27% des semences viables sont localisées respectivement dans les horizons 0–20 et 20–40 cm.