bluuebunny/crossref_metadata_2025_split huggingface dataset:
Factors affecting glyphosate activity in Imperata cylindrica (L) Beau, and Cyperus votundus L. I. Effect of soil moisture
Authors: MOOSAVI‐NIA H. , DORE J. 
Published: September 2010

Summary:Established Greenhouse grown plants of cogongrass Imperata cylindrica (L) Beauv.) and purple nutsedge (Cyperus rotundusL.) were given three different soil moisture regimes; field capacity, moderate stress and extreme stress, followed 6 weeks later by glyphosate [(N‐phosphonomeihyl) glydne] applications to the shoots at 0.2,0.4 and 0.8 kg/ha for Imperata and 0.3,0.6 and 1.12 kg/ha for Cyperus. Field capacity watering stimulated most vegetative growth in hoth species. Glyphosate given at field capacity decreased shoot dry weight in both species, and rhizome length, rhizome dry weight and total carbohydrate in Imperata and total number of tuber‐bulbs in Cyperus. In contrast. at extreme soil moisture stress, glyphosate showed reduced activity which appeared to be related to the physiological and morphological behaviour of the plants arising from the drought trealment. Application of waier to the roots of the plants grown at soil moisture stress. I week before and I week afler glypbosate spraying, enhanced glyphosate activity, probably because of the recovery of processes disturbed by ibe soil moisture deficit.
Simulation of the persistence of atrazine, linuron and metolachlor in soil at different sites in the USA
Authors: WALKER A. , ZIMDAHL R. L. 
Published: September 2010

Summary:The effects of soil temperature and soil moisture content on the rates of degradation of atrazine, linuron and metolachlor were measured in the laboratory in soil from different sites in the USA. Persistence of the herbicides was measured in the same soils in the field during the summers of 1978 and 1979. Weather records from the different sites for the periods of the field experiments were used in conjunction with appropriate constants derived from the laboratory data in a computer program to simulate persistence in the field. There was a general tendency for the model to overestimate the observed soil residues. For example, with atrazine, 40 of the 48 measured residues were lower than those predicted by the model; seven were more than 30% below and two were more than 50% below. With metolachlor, 16 of the 48 measured residues were more than 30% below those predicted and six were more than 50% below; almost identical results were obtained with linuron. When the model overestimated late‐season residues by a large amount, the discrepancies between predicted and observed data were usually apparent from early in the experiment. Possible reasons for the discrepancies are discussed.
Weed control in direct‐seeded lowland rice under poor water control conditions
Authors: AKOBUNDU I. OKEZIE 
Published: September 2010

Summary:Several herbicides applied singly and in combination were evaluated for weed control and for their effects on crop yield in direct‐seeded lowland rice under poor water management conditions characteristic of the conditions in which lowland rice is grown by most farmers in West Africa. Several herbicides including cyperquat at 3.0 kg/ha, a mixture of cyperquat and 2,4‐D at 2.0 + 0.5 kg/ha, bentazon at 2.0 kg/ha and avirosan satisfactorily controlled sedges in the 3‐year study. Crop yield was consistently high in plots where weeds were controlled with post‐emergence application of MCPA + propanil at 1.0+1.7 kg/ha, propanil + thiobencarb 2.2+1.2 kg/ha, oxadiazon 1.5 kg/ha, bentazon 2.0, granular 2,4‐D at 1.0 kg/ha, and a pre‐emergence application of bifenox at 2.0 kg/ha. Crop yields in plots treated with these herbicides were generally better than with two hand‐weedings.
Germination of Orobanche crenata Forsk. seeds in vitro
Authors: PIETERSE A. H. 
Published: September 2010

Summary:The effects of calcium hypochlorite [Ca(OCl)2] and gibberellic acid (GA), both in combination and separately, were studied on the germination of Orobanche crenata seeds. Hypochlorite was applied either before or after the conditioning phase for periods up to 150 min. The seeds were exposed to GA during the conditioning phase. After conditioning the seeds were exposed to either the synthetic germination stimulant GR 7, flax root exudate (FRE) or distilled water.GR 7 exploited the germination potential of O. crenata better than FRE and this in turn better than water. In the presence of GR 7 or FRE the number of germinating seeds generally increased when the seeds were briefly (5–20 min) exposed to hypochlorite. In the absence of GR 7 and FRE, hypochlorite only increased germination if the seeds were treated during medium‐long periods (20–60 min) after conditioning. If GR 7 or FRE were not applied the germination percentage was usually significantly higher when conditioning was done in the presence of GA.
Influence of picloram on Cirsium arvense (L.) Scop, control with glyphosate
Authors: O'SULLIVAN P.A. , KOSSATZ V.C. 
Published: September 2010

SummaryLow rates of picloram in mixture with glyphosate provided a rapid enhancement of the onset of injury to the shoots of Cirsium arvense (Canada thistle or creeping thistle) under field (0.07+1.0 and 0.07+1.5 kg ha−1) and greenhouse (0.035+0.42 and 0.07+0.84 kg ha−1) conditions. Picloram slightly reduced the amount of 14C‐glyphosate absorbed at 24 and 48 but not 72 h after treatment. Movement of 14C‐glyphosate from the treated leaves to the shoot apex, remainder of the shoot and roots was reduced in the presence of picloram. Necrosis of the treated leaves above the treated spots was evident, presumably indicating acropetal movement of either or both herbicides. With the picloram + glyphosate mixtures there was increased shoot regrowth over glyphosate alone at 1 year after treatment under field, and with certain mixtures at 18 days and 4 weeks after treatment under greenhouse conditions. Following application of the mixtures, accumulation of glyphosate in the shoots may be responsible for the enhanced onset of shoot injury while failure of enough glyphosate to translocate to, and cause death of, the roots may be responsible for the increased shoot regrowth over glyphosate alone.
Competition between Avena sterilis ssp. macrocarpa Mo. and cultivars of wheat
Authors: PONCE R. GONZÁLEZ 
Published: September 2010

SummaryA pot experiment was done in the glasshouse to study the competition between Avena sterilis ssp. macrocarpa Mo. and six wheat cultivars of different lengths of growth cycle. The competitiveness of wild oat was similar for all six wheat cultivars with respect to grain weight, straw weight, number of ears and total accumulation of nitrogen. The cultivar with the longest cycle was the most affected by wild oat competition as regards height, because a large part of its stem extension and some of the heading took place after the panicles of wild oat had expanded. Wild oat competition with wheat plants was greater than the competition among wheat plants themselves. The wild oat had a similar tolerance to all the wheat cultivars.
Analyse expérimentale des effets de concurrence d'une graminée adventice dans un blé de printemps en relation avec le désherbage
Authors: CAUSSANEL J. P. , KAFIZ B. , CARTERON A. 
Published: September 2010

RésuméDans une expérience de plein champ, où tous les facteurs déographiques et génétiques de concurrence étaient déterminés, des densités différentes d'une variété d'avoine de printemps (espèce considérée comme une graminée adventice) ont étéétablies dans une culture de blé de printemps. Sur la moitié des parcelles du dispositif expérimental, l'avoine a été détruite par une application de diclofopméthyl au stade 3 talles du blé. Les mauvaises herbes dicotylédones ont été désherbées soit à la même date que celle du traitement au diclofopméthyl (traitement précoce), soit deux semaines plus tard (traitement tardif). Les poids secs de la plants cultivée el des adventices ont été mesurés plusieurs fois au cours du cycle de la culture sur des échantillons. Toutes les densités de l'avoine de printemps ont réduit le rendement et certaines composantes du rendement du blé en fonction du traitement herbicide: les rendements du blé ont été moins diminués sur les parcelles traitées que sur les parcelles témoins, les mauvaises herbes dicotylédones ont été mieux détruites par le traitement précoce que par le traitement tardif au 2,4‐D. D'après les résultats oblenus, l'existence d'interactions herbicides est susceptible de modifier les effets de compétition adventice.
Effects of herbicide and timing of removal on interference between barley and weeds
Authors: ISMAIL A. M. A. , HASSAN A. H. A. 
Published: September 2010

SummaryField experiments were done during the rainy season of 1984–85 and 1985–86 at Harma, Qatar. A weed survey of barley fields was conducted with the primary purpose of identifying the weed vegetation present. The effects of time of hand‐weeding and of application of the herbicide metoxuron on the yield and yield components of barley were studied. Removing weeds at 15,30,45 and 60 days after sowing gave yields similar to that of the clean‐weeded check. Neither a critical period nor a threshold density below which no yield loss occurred were observed. Metoxuron (1,2 and 3 kg ha−1) gave good to excellent broad‐leaved and grass‐weed control. The use of this herbicide at the rate of 1 kg ha−1 showed considerable promise.
Control of Galium aparine (cleavers) in winter cereals with mecoprop alone or with ioxynil plus bromoxynil
Authors: LUTMAN P. J. W. , THORNTON M. E. , LOVEGROVE A. W. 
Published: September 2010

SummaryA series of eleven field experiments over two seasons investigated the control of Galium aparine (cleavers) with mecoprop and a proprietary mixture of ioxynil plus bromoxynil. Applications of mecoprop (2⋅4 kg a.e. ha−1) between December and March gave variable results but a mixture of ioxynil + bromoxynil (0⋅6 kg a.i. ha−1) and mecoprop improved control up to at least 90%, at most sites. Applications of mecoprop alone in April were most effective and frequently achieved more than 90% control. In May, when the G. aparine plants were very large, it was less successful. The reasons for the environmental effects on performance are discussed. Preliminary examination of the effect of soil temperature on mecoprop activity indicates that the reliability of control increases with increasing temperature (0–12°C). An average of 94% control was achieved when soil temperatures were greater than 6°C. La destruction de Galium aparine (Gaillet) dans les cereales d'hiver avec du mecoprop seul ou avec ioxynil plus bromoxynil
Regenerative capacity of rhizomes and tubers from two populations of Helianthus tuberosus L. (Jerusalem artichoke)
Authors: SWANTON C. J. , CAVERS P. B. 
Published: September 2010

SummaryThe regenerative responses of rhizomes and tubers from two populations of Helianthus tuberosus L. to burial and fragmentation were studied in field experiments. The regeneration of both populations varied with planting depth and stage of growth at which fragmentation occurred. Shoots of both populations emerged from rhizomes or tubers planted to depths of 30 cm. The percentage of tubers that regenerated was higher than that of rhizomes, particularly from deeper planting depths. The regeneration from rhizomes and tubers of a riverbank population was greater than that of a‘weedy’population. Rhizomes and tubers from both populations that had failed to produce shoots I year after planting were found to have decomposed completely. The significance of these results in relation to the distribution and control of H. tuberosus is discussed.
Dormancy studies in three populations of Poa annua L. seeds
Authors: STANDIFER L. C. , WILSON P. W. 
Published: September 2010

SummarySeeds of Poa annua from original collections in Louisiana, Maryland and Wisconsin were grown together in Louisiana over a 3‐year period. The freshly harvested seeds and samples stored in moist soil at 30°C were tested for germination at a range of temperatures to compare dormancy and germination characteristics. Seeds of the Louisiana population were dormant over the germination temperature range of 5–25°C, and imbibed storage for 2 weeks did not break dormancy. Freshly harvested seeds of the Maryland population germinated well (78%) at 10°C. With 1 week of imbibed storage at 30°C, germination was good over the range from 5 to 15°C and near 50% at 20°C. Storage for 2 weeks had little further effect. Freshly harvested seeds of two Wisconsin populations germinated above 50% throughout the range of temperatures, and imbibed storage for 2 weeks at 30°C had no effect on germination. The variations in the dormancy of freshly harvested seeds and the varying responses of dormancy breaking from storing imbibed seeds at 30°C suggests that these populations have adapted to avoid high summer temperatures in Louisiana and Maryland but to grow as a summer annual in Wisconsin.
A high temperature requirement for after ripening of imbibed dormant Poa annua L. seeds
Authors: STANDIFER L. C. , WILSON P. W. 
Published: September 2010

SummaryFreshly harvested seeds of Poa annua L. collected in south Louisiana were stored in moist soil at seven temperatures between 5°C and 35°C. At monthly intervals, seed lots were removed and germinated at each of the seven temperatures. Seed were dormant for at least 1 month at all test temperatures. Seeds stored for 2 months at 30 and 35°C showed conditional dormancy; there was 100% germination at 10 or 15°C, and poorer germination at 5 or 20°C. Seeds started to lose viability after 2 months at 35°C and were dead after 7 months. In seeds stored at 10–30°C, there were increased percentages and a wider range of germination temperatures as storage time or storage temperatures increased. Seeds stored at 10°C remained dormant for 9 months, but by 12 months of storage the seeds germinated only at 5 or 10°C. Nearly all seeds stored at the same temperatures in air dry soil remained dormant for 6 months, regardless of storage temperature. These results differ from other reports of low temperatures breaking seed dormancy in Poa annua L. and suggest an adaptation to subtropical climates.
Inheritance of resistance to paraquat in barley grass Hordeum glaucum Steud.
Authors: ISLAM A. K. M. R. , POWLES S. B. 
Published: September 2010

SummaryTwo biotypes of the grass weed barley grass (Hordeum glaucum), one resistant and the other susceptible to the herbicide paraquat, were studied along with their F1, F2 and F3 progeny to determine the inheritance of paraquat resistance. The plants were sprayed with 50–200 g a.i. paraquat ha−1. These concentrations killed the susceptible type. The data obtained from segregating populations indicated that paraquat resistance in H. glaucum is controlled by a single nuclear gene with incomplete dominance.
Seed survival and patterns of seedling emergence studies of Rottboellia cochinchinensis (Lour.) W.D. Clayton in cultivated soils
Authors: BRIDGEMOHAN P. , BRATHWAITE R.A.I. , MCDAVID C. R. 
Published: September 2010

Summary:The longevity of buried Rottboellia cochinchinensis (Lour.) W.D. Clayton seed represents a major survival mechanism for the weed, enabling the persistence of a continuing source of weed seeds in crop land. The pattern of seed persistence and depletion of R. cochinchinensis in cultivated maize soils was investigated by means of (1) studies on the effect of depth and duration of burial on the viability of the weed seeds, (2) quantitative estimation of the seed population and viability in cultivated fields, and (3) the periodicity of emergence and effects of cultivation on seed germination both in the field and in the greenhouse. The results indicated that the mode of persistence was innate (8.5%) and enforced (35%) dormancy after 1 year of burial, and that the persistency component of the seed population on cultivated soils ranged from 40.60%. The weed was able to remain viable at depths of 45 cm, indicating an excellent mechanism of escaping the effects of most soil‐applied herbicides, and it was shown that tillage increases the depletion rate of the weed seed reserve by 32% per year.
Uptake and efflux of chlorimuron ethyl by excised soybean (Glycine max (L.) Merr.) root tissue†
Authors: NANDIHALLI U. B. , BHOWMIK P. C. 
Published: September 2010

Summary:Chlorimuron ethyl uptake into excised soybean root tissue was investigated using 14C‐labelled herbicide. Chlorimuron ethyl accumulated in the root tissue, reaching a maximum concentration after 2 h and then declining over the next 2 h. The herbicide did not accumulate against a concentration gradient. The tissue concentration was linearly correlated with the external herbicide concentration. The Q10 between 15 and 25°C was 1.6. Addition of KCN and anoxia reduced uptake. The efflux of 14C that had accumulated in root tissue segments occurred in two phases: a rapid phase with a T½ value of 6.3 min and a slower phase with a T½ value of 172 min. Chlorimuron ethyl uptake and efflux in excised soybean root tissue closely resembled that previously observed in velvetleaf, a sensitive weed species.
Alkoholyse und saure Hydrolyse von Chlorsulfuron
Authors: SABADIE J. 
Published: September 2010

Résumé:L'alcoolyse du chlorsulfuron (méthanol, étha‐nol) implique seulement la fonction urée de la molécule. La formation de carbamate permet de postuler l'existence d'isocyanate intermédiaire. Deux voies de dégradation sont observées au cours de l'hydrolyse du chlorsulfuron en solution aqueuse acide: hydrolyse de la fonction urée et hydrolyse du substituant méthoxy. L'augmentation de la température (25 à 55°C) favorise la vitesse de conversion et l'hydrolyse de la fonction urée. L'abaissement du pH (6 à 2,4) accé1ère fortement le processus et diminue son énergie d'activation sans en modifier la sélectivité. Les effets d'autres facteurs (cations de métaux de transition, argiles) demeurent généralement limités.
Predicting the competitive effects of weed and crop density on weed biomass, weed seed production and crop yield in wheat
Authors: WILSON B. J. , WRIGHT K. J. , BRAIN P. , CLEMENTS M. , STEPHENS E. 
Published: September 2010

SummaryCompetition between winter‐sown wheat and Viola arvensis Murray or Papaver rhoeas L. was studied in two experiments in two successive years. The effects of varying crop and weed density were modelled in terms of weed biomass over time, weed seed production and crop yield. Biomass model parameters, representing maximum weed biomass and intra‐ and interspecific competition, were obtained for different assessment dates, enabling biomass levels to be predicted during the two growing seasons. Weed biomass declined, and its maximum level was reached earlier, with increasing crop density. Intraspecific competition was higher in the absence than in the presence of crop, increasing with time and with weed density. Halving the wheat population increased June biomass of V. arvensis by 74% and of P. rhoeas by 63%. Crop yield losses with increasing weed density were greater with low than with medium and high crop populations. P. rhoeas was significantly more competitive than V. arvensis in both years. Weed biomass in 1989 responded more to reductions in crop density following the milder winter of 1988/89 than in the previous year; however crop yields were less affected in 1989 due to summer drought, restricting late weed growth and competition. Weed seed production was related to weed biomass; the progressive lowering of crop density increased seed production, and both species were very prolific in the absence of crop. By combining models, seed production could be derived for a given competitive effect on the crop. Threshold weed populations, based on low weed levels that are not economic to control, could then be equated with the accompanying weed seed production.
Factors affecting benfuresate activity against purple nutsedge (Cyperus rotundas L.)
Authors: FISHLER A. , CASELEY J. C. , VARSANO RINA , NEGBI M. , RUBIN B. 
Published: September 2010

SummaryBenfuresate (2‐3‐dihydro‐3,3‐dimethylbenzofu‐ran‐5‐yl ethanesulfonate) is a selective herbicide for the control of purple nutsedge in cotton. Under outdoor conditions, purple nutsedge was sensitive to benfuresate incorporated in soil up to eight days after initiation of shoot sprouting from the tuber. Older seedlings recovered from the damage. During the period of susceptibility to benfuresate, young shoots more sensitive than the roots. Under controlled environmental conditions, benfuresate applied directly to apical buds developing from the tuber caused severe damage to the treated bud and induced abrupt development of axillary buds. Negligible amounts of the applied herbicide were translocated from the treated part to the other buds and roots. Application of the herbicide to fully developed leaves had no effect, probably because of its rapid metabolism and low basipetal mobility. Its relatively high volatility may also contribute to its low foliar post‐emergence activity. Tubers also absorbed herbicide vapours. Root uptake of 14C‐benfuresate resulted in a rapid accumulation of 14C in the shoot, which had no effect on the purple nutsedge plant, regardless of concentration. The herbicide is rapidly converted, mainly to a non‐phytotoxic polar product. These results may explain the high sensitivity of the weed to benfuresate at early growth stages, and the lack of sensitivity in mature plants.
Mikania micrantha H. B. K. in China – an overview
Authors: Zhang L Y , Ye W H , Cao H L , Feng H L 
Published: September 2010

SummaryAs one of the worst invasive weeds in the world, Mikania micrantha H. B. K. spread to southern China after 1910 but without any natural enemies. Since the 1980s it has started to spread and invade widely. The weed has caused significant damage to many ecosystems in Guangdong province in recent years. This paper reviews the research in China on this weed, including its description, history of introduction together with information from morphological and physiological studies. The distribution of this invasive plant in China has been mapped and is presented together with damage being caused and analyses of soil types infested. The measures taken by the Chinese government for prevention and elimination are also discussed. Chinese scientists are now looking for effective biocontrol options to deal with this deleterious plant. Several native insects, mites and fungi have been reported to be able to control the reproduction of this weed in China, but no natural control has been achieved. Cuscuta sp., a native autoecious vine has recently been shown to suppress the growth of M. micrantha. Three major causes for the massive spread of this weed in southern China are presented together with recommendations for future control activities.
The competitive interactions between winter barley andAvena sterilisare site‐specific
Authors: RUIZ D , BARROSO J , HERNAIZ P , FERNÁNDEZ‐QUINTANILLA C 
Published: September 2010

SummaryCompetition between winter barley andAvena sterilisis expected to depend on the specific conditions present in a given site. Considering that site conditions may be variable within a field, we hypothesised that the lower densities ofA. sterilisfrequently observed under more favourable soil conditions can be attributed to the improved growth and competitiveness of the barley crop under those conditions. Artificial populations ofA. steriliswere established at three sites with different soil properties, both in the absence and the presence of a barley crop. Plant density, total biomass, dry weight per plant, seed production and seed per plant production were measured at different times in two growing seasons.Avena sterilisproved to be a generalist species when growing in monoculture, with similar seed production, regardless of the site conditions. However, when growing with the crop, differences in growth and seed production were observed at the different sites under some climatic conditions. The effect of the crop onA. sterilisbiomass and seed production was more pronounced at the sites with finer textures and higher organic matter and nitrogen contents, suggesting that barley site‐specific competitive ability may contribute to limiting weed populations in favourable soils.