bluuebunny/crossref_metadata_2025_split huggingface dataset:
Untersuchungen über Sonchus arvensis L. III, Metabolismus von MCPA
Authors: FYKSE HALDOR 
Published: July 2006

Zusammenfassung: 14C‐MCPA wurde beim Auspflanzen der Wurzelstückchen, und wenn die Pflanzen 3 cm, 5–7 cm und 12–15 cm lange Blätter entwickelt hatten, in die Wurzeln von Sonchus arvensis L. injiziert. Nach Extraktion mit 70%‐igem Äthanol und Trennung auf Dünnschichtplatten konnten durch Scanning drei hier als 1, 2 und 3 genannte Komponenten nachgewiesen werden. Komponente 2 chromatographierte wie MCPA und bestand aller Wahrscheinlichkeit nach aus dem nichtmetabolisierten Rest der injizierten Substanz. Komponente 3 wurde schneller als Komponente 1 gebildet, aber beide Komponenten wurden unter Einfluss von 1N HCl oder 1N NaOH+Wärme zur Komponente 2 (MCPA) verwandelt. Komponente 3 unterschied sich wieder von Komponente 1 durch ihre höhere Umwandlungsgeschwindingskeit.Der Metabolismus von MCPA verlief um so schneller, je älter die Pflanzen waren, und war in Mutterwurzeln rascher als in Tochterwurzeln und Blättern. Dormante Wurzeln zeigten eine Fähigkeit MCPA zu metabolisieren auf, die wenigstens nicht geringer als bei nicht‐dormanten Wurzeln war. Weiter verlief der Metabolismus schneller bei 23° als bei 70.Abspaltung von 14CO2 war ein langsamer Prozess, und nach 4 Tagen machte die Aktivität des ausgeschiedenen 14CO2 nur 1,3% der Gesamtaktivität aus.In Biotesten mit Raphanus sativus L. als Testpflanze, zeigte Komponente 3 eine entsprechende Phytotoxizität wie Komponente 2 (MCPA) auf, während die stabilere Komponente 1 sehr wenig phytotoxisch war.
The effect of soil aggregate size and water content on herbicide concentration in soil water
Authors: HANCE R. J. 
Published: July 2006

Summary:Suspensions of wettable powders of metribuzin and simazine were sprayed onto samples of two soils of two particle size grades, > 2.5 mm and <0.5 mm. The soils were either air‐dry or at a water content of 12%. After either 1 h or 1 week, water was added to give a soil to water ratio of 1:1. Samples of solution were analysed after 1, 24 and 48 h.With metribuzin the intial concentration for both soils after wetting was greater from the >2.5 mm samples than the <0.5 mm samples, following application to dry soil, but by 48 h the differences were negligible. With simazine WRO soil did not show this effect at all and with Kirton soil only small differences were seen. If the soil was wet at the time of application, particle size had no effect except with simazine in Kirton soil.Generally metribuzin concentrations were higher after application to wet than to dry soils for at least 24 h after wetting whereas simazine concentrations were higher from initially dry soils and the differences had virtually disappeared 24 h after wetting.With the WRO soil herbicide concentrations in soil water were higher if the soil was wetted 1 h after spraying than if left for 1 week but the differences rarely persisted for 48 h. No such trend was observed with Kirton soil.It is concluded that the differences observed in these experiments could be responsible for variations in the performance of soil‐applied herbicides.
Factors affecting seed germination ofEchium plantagineumL. andTrifolium subterraneumL.
Authors: PIGGIN C. M. 
Published: July 2006

Summary:Echium plantagineumL. is a widespread, persistent, and often dominant volunteer species in southern Australia. This paper describes laboratory and field experiments investigating seed germination in E. plantagineum and a commonly associated species, Trifolium subterraneum L. In the laboratory, E. plantagineum germination was favoured by relatively high temperatures, and the seed showed considerable innate and temperature‐enforced dormancy. In the field, this dormancy appeared to prevent some germination in response to rainfalls immediately after seed formation, and permitted sporadic germination during summer and autumn in subsequent years. In 1972 and 1974, both species emerged well in autumn whilst E. plantagineum was favoured in summer and T. subterraneum was favoured in winter. No seedlings emerged in spring. Emergence appeared to be controlled primarily by moisture availability and temperature but also was affected by cultivation and removal of soil‐surface litter. The results of these seed germination studies show that E. plantagineum is well adapted to persist in a Mediterranean‐type climate, and will be favoured in years with early seasonal breaks. T. subterraneum is likely to be favoured with later breaks.
Weed competition in spring‐planted strawberries
Authors: LAWSON H. M. , WISEMAN J. S. 
Published: July 2006

Summary:Annual weeds germinating after planting strawberry (Fragaria chiloensis (L.) Duch. cv. Cambridge Favourite) in late March had no effect on crop growth if removed by late May. Dense weed cover thereafter severely inhibited stolon growth, virtually eliminating it if allowed to remain beyond mid‐August. Shading by weeds inhibited leaf production and caused etiolation of existing leaves. New leaves appeared shortly after weed removal and few plants died unless weed cover persisted for most of the growing season. Further weed germination was allowed on some plots. Although not removed until late autumn, these weeds only had adverse effects on crop growth where initial weeding had occurred before mid‐June.In one experiment, delaying weed removal until 6 July, 31 August or 2 November in the first year reduced fruit yield in the second (weed‐free) year by 34%, 54% and 67% respectively. In a later experiment, competition from weeds until July or later in the first growing season gave fruit yields similar to those in the first experiment, but totally weed‐free plots and those kept clean after weeding in mid‐June produced less fruit than plots which remained weedy between mid‐June and mid‐August. It is suggested that competition from uncontrolled stolon growth in this experiment severely inhibited crown and hence truss production on plots which did not suffer weed competition. Unless left untouched until early September, weeds had less adverse effect on truss production than the stolons which they displaced.The results are interpreted in relation to improving the efficiency of weed control techniques.
Quantitativer Biotest zur Bestimmung von Photosynthesehemmern im Boden
Authors: PESTEMER W. 
Published: July 2006

Zusammenfassung:Ein quantitativer Biotest zum Nachweis von Photosynthese‐hemmern in Böden, Hydrokultur und Zellstoffwatte wird beschrieben. Als Testpflanze erwies sich Gartenkresse (Lepidium sativum L.) als sehr gut brauchbar. Anhand von Beispielen mit Monolinuron und Methabenzthiazuron werden einige Anwendungsmöglichkeiten Bestimmung der herbiziden Wirksamkeit, Pflanzenverfügbarkeit und Ermittlung der ED5o‐Werte in verschiedenen Bden gegeben. Für Monolinuron z.B. konnten Konzentrationen von <0.04 ppm quiintitativ nachgewiesen werden.Photosynthesehemmerzeigen auf Keimung und Wachstum der Kressesämlinge erst nach 5 Tagen einen Effekt; denn eine Beeinträchtigung des Wachstums tritt erst dann ein, wenn die Reservestoffe des Endosperms aufgebraucht sind. Da her wurden die Reservestoffe in den Kressekeimlingen im Dunkelkeimversuch ermittelt und von alien Ergebnissen abgezogen, um ausschlieBlich die gebildete Trockenmasse bei Herbizideinwirkung zu erfassen.
Relationships between substituted urea herbicides and soil urease activity
Authors: CERVELLI STEFANO , NANNIPIERI PAOLO , GIOVANNINI GIACOMO , PERNA AMALIA 
Published: July 2006

Summary:Fenuron, monuron, diuron, siduron, linuron and neburon were tested for their inhibition of soil urease activity in order to investigate relationships between fertilizers and herbicides.The inhibition of urea hydrolysis in the selected soils was 10–33% for fenuron, 10–39% for monuron, 10–35% for diuron, 8–38% for siduron, 9–36% for linuron and 12–30% for neburon. In the field greater effects might be expected since the fertilizer/herbicide ratio would be lower than the one considered here.Some agronomic aspects of the relationship between fertilizers and herbicides are discussed.
Effects from simulated rainfall on shoot‐zone uptake of herbicides
Authors: WALKER A. 
Published: July 2006

Summary:In glasshouse experiments, atrazine, simazine, lenacil and linuron applied to the soil surface were phytotoxic to turnip seedlings which had emerged from a depth of 1–5 cm when 3 mm artificial rainfall was applied at the time of seedling emergence or shortly afterwards. When rainfall was applied on 2 or 3 consecutive days, the herbicides were in general more phytotoxic. As the delay between emergence and commencement of surface watering increased, however, the response of the seedlings decreased.Studies with [14C]‐atrazine showed that at emergence the seedlings contained a small amount of herbicide which increased considerably with surface watering. Relatively high concentrations were attained when rainfall was applied while the seedlings were small, but as the interval between seedling emergence and rainfall increased, the same uptake resulted in lower shoot concentrations, Atrazine extraction from the soil showed little movement from the surface 1.0 cm, suggesting uptake via the stem. The observed responses of the other three herbicides are explained by assuming the same pattern of uptake as that recorded for atrazine.
Asulam mixtures for weed control in flax
Authors: CHOW P. N. P. 
Published: July 2006

Summary:Five field experiments were conducted from 1972 to 1975 to evaluate weed control in flax (Linum usitatissimum L.) using post‐emergence treatments of asulam [methyl (4‐aminobenzenesulphonyl) carbamatel alone and in combination with other herbicides. The 14C‐asulam absorption by leaf segments and roots of glasshouse grown wild oats (Avena fatua L.) was also investigated. Asulam at 1.12 kg/ha gave good wild oat control and acceptable control of green foxtail (Setaria viridis (L.) Beauv.). However, wild oat control was poorer when asulam was combined with other herbicides: on a 3‐year average, as compared with asulam alone at equal rates, the asulam+MCPA mixture resulted in a greater antagonism and a significant 6% reduction in flax seed yield, whereas the asulam+bromoxynil/MCPA mixture gave the least antagonistic effect, improved broadleaf weed control and increased yield by 13%. In mixtures, the potassium salt of MCPA was more compatible with asulam for weed control than the amine form. Both leaf segments and roots of wild oats absorbed and distributed less 14C‐asulam from solutions containing MCPA than from those containing bromoxynil or bromoxynil/MCPA.
Growth of seedlings of Agropyron repens L. Beauv. and Agrostis gigantea Roth. in wheat and barley: effect of time of emergence, nitrogen supply and cereal seed rate
Authors: WIlLLIAMS E. D. 
Published: July 2006

Summary:As part of a programme of work evaluating the role of seeds in regenerating or initiating infestations of Agropyron repens and Agrostis gigantea, the growth of the weeds was analysed in cereal crops in two experiments. The first experiment investigated the effects of time of planting the weed seedlings (simulating different times of emergence), nitrogen supply and cereal seed rate in winter wheat and the second, the same factors in spring wheat and spring barley.In winter wheat, delaying planting of the weeds from autumn until spring greatly decreased shoot growth and almost completely prevented rhizome formation. Nitrogen fertilizer increased the weight of shoots of both species planted at both times but whereas it increased the amount of rhizome produced by Agropyron it decreased that of Agrostis. Without nitrogen Agrostis had twice as much rhizome as Agropyron but with nitrogen Agropyron had twice as much as Agrostis. Decreasing the cereal seed rate had little effect on rhizome weight when nitrogen was not given but it allowed twice as much rhizome to be produced when it was supplied. However, more longer rhizomes were formed at the smaller than at the larger seed rate with both amounts of nitrogen.In spring cereals, late planting decreased the shoot growth of Agrostis more than that of Agropyron, and of Agropyron in barley more than in wheat, especially at the smaller seed rate. Nitrogen increased shoot weight of Agropyron in wheat but had little effect in barley; it decreased that of Agrostis in barley. On average, rhizome growth was decreased by nitrogen, by increasing the seed rate and by delaying planting. Agropyron rhizomes were heavier in wheat than in barley but those of Agrostis were heavier in barley than in wheat. Agropyron produced most rhizome in thinlysown wheat given nitrogen, but Agrostis most in thinlysown barley without nitrogen. The two treatments had an equal number of rhizomes longer than 100 cm.The agricultural significance of the interaction of the various treatments is briefly discussed.
Competition from weeds and their control in direct‐seeded rice
Authors: SHARMA H.C. , SINGH H.B. , FRIESEN G.H. 
Published: July 2006

Summary:In direct‐seeded upland rice (Oryza sativa L.) yield reductions due to weed competition ranged from 42 to 65% in field experiments conducted in eastern Utter Pradash, India. The most critical period, when crop losses due to weed competition were most severe, ranged from 10 to 20 days after emergence. Yields generally continued to increase, however, as the length of the weed‐free period increased. The weed flora consisted of various grasses, sedges and broadleaved species. The most effective herbicide treatment evaluated was a pre‐emergence application of alachlor followed by a post‐emergence application of propanil or one mechanical weeding.
The adsorption and degradation of glyphosate in five Hawaiian sugarcane soils*
Authors: NOMURA N.S. , HILTON H.W. 
Published: July 2006

Summary:The rate of aerobic evolution of 14CO2 from 14C‐glyphosate labelled in the methylphosphonyl carbon, varied 100‐fold within a group of five Hawaiian sugarcane soils. The rate depended inversely on the degree of soil binding, probably associated with the phosphonic acid moiety, and to a less certain extent on soil pH and soil organic matter. After an initial rapid degradation, the rate of 14CO2 evolution in three soils reached a constant at 16–21 days which continued to the 60‐day termination. The other two soils showed a continually decreasing rate throughout. Two soils released over 50% of the labelled carbon in 60 days, a third released 35%, while the remaining soils released 1.2 and 0.8% respectively.Labelled carbon in the soils after 60 days consisted of glyphosate and one metabolite, aminomethyl‐phosphonic acid, with glyphosate predominating in high fixing soils. The 14C could be extracted almost completely with NaOH solution, and remained mainly in solution after acidification.
Effect of trickle irrigation on soil‐applied herbicides*
Authors: KOREN E. , SHLEVIN E. 
Published: July 2006

Summary:The effect of trickle irrigation on the activity, leaching and distribution in the soil of herbicides, was studied in a model specially constructed for simulating trickle irrigation in the field, and also under field conditions.The pattern of movement of a soil‐applied herbicide in the soil under trickle irrigation paralleled, to some extent, that of the trickle water itself, but total herbicide movement was less than that of the water. Both water and herbicide distribution in the soil formed the shape of a hemisphere or cone under the trickle nozzle, the exact shape of which was determined by the soil characteristics (a narrow cone in a light soil and a wide cone in a heavy soil); cone size was determined by the amount of trickle water.Bioassays with susceptible test plants showed that effective weed control could be expected with either simazine or GS‐14259 (2‐t‐butylamino‐4‐ethylamino‐6‐methoxy‐s‐triazine =‘Caragard') only in the areas wetted by the trickle nozzle.The results showed that the pattern of distribution in the soil of simazine and GS‐14259 was similar, but there were quantitative differences in their final spread.
Persistence of terbacil and trifluralin under different soil and climatic conditions
Authors: RAHMAN A. 
Published: July 2006

Summary:Soil samples were collected from forty‐three field trials conducted on ten soil types to investigate the residual activity of terbacil and trifluralin at the end of the cropping season, approximately 6 months after application. The soil was bioassayed in a glasshouse using soya beans and German millet for terbacil and trifluralin respectively. At 1 kg/ha terbacil phytotoxic residues occurred in a majority of the trials, while at 2 kg/ha such a carry‐over could be found in every case. Trifluralin doses of up to 1 kg/ha did not persist in toxic amounts in most soils, while application of 2 kg/ha showed residual activity in 74% of the trials and application of 4 kg/ha killed German millet in all instances. Results are also presented from the time‐rate dissipation studies conducted on both herbicides by assaying soil samples collected at monthly intervals.Both organic matter and clay content of the trial sites affected the persistence of terbacil, while trifluralin residues were influenced only by the soil organic matter content. Trial sites receiving high rainfall showed considerably less residues of terbacil, but the persistence of trifluralin was not affected by rainfall to any appreciable extent.
An agro‐economic survey of the weeds and weeding practices in cassava (Manihot esculenta Crantz) in Colombia
Authors: DOLL JERRY , PINSTRUPANDERSEN PER , DÍAZ RAFAEL 
Published: July 2006

Summary:A survey of weeds and weeding practices was carried out by a team of agricultural economists and agronomists on 283 farms in five Cassava growing regions of Colombia at three times during a cropping season.Seventy‐one to 78% of all weed species present were broadleaved species. As cassava grew older, grass species were present to a greater and sedge species to a lesser relative frequency. Surprisingly Pteridiumaquilinum (L.) Kuhn was the most frequently listed species and Bidens pilosa L. and Cyperus rotundus L. were other frequent problems. Regional variations in the most frequently encountered species were found but several of the weeds were common to many zones. The most frequently encountered species did not usually have the highest plant populations. Most of the annual grasses, sedges and broadleaf weeds found can be controlled by currently recommended herbicides for cassava but further research is needed on Imperata cylindrica (L) Beauv., Melinis minutlftora Beauv., P. aquilinum and Sida spp.The average number of manual weedings was 3.3 per crop, occupying 48 man‐days/ha which is 50% of the total labor requirements for cassava production, and more than one‐third of the total costs. Reasons for not using herbicides were (1) relative costs of herbicides and labor. (2) lack of information, (3) lack of capital, (4) right herbicides were not available, and (5) herbicides were not available in small packages.This survey has usefully identified new field problems and has suggested further research programs to solve them.
Alachlor placement in the soil as related to phytotoxicity to maize (Zea mays L.) seedlings*
Authors: NARSAIAH D. BALA , HARVEY R. G. 
Published: July 2006

Summary:Growth chamber studies were conducted to investigate the effects of alachor (2‐choloro‐2′,6′‐diethyl‐N‐ (methoxymethyl) acetanilide) on emerging seedlings of maize (Zea mays L.) planted 2.5 and 8.0 cm deep in a Plano silt loam soil. Alachlor was localized in the shoot zone, in the root zone, and in the shoot and root zones. Four days after emergence, seedlings were harvested and total shoot and root lengths used as measures of herbicidal effectiveness. The herbicide applied at a rate of 2.5 kg/ha caused a severe reduction in seedling height when placed in the shoot zone of seeds planted at the shallow depth. This injury was prevented when seeds were planted at the deeper level. When alachlor was placed in the root zone, there was no inhibition of shoot growth. When both shoot and root zones were exposed to the herbicide, severe growth inhibition again occurred. Roots were less sensitive to alachlor. A simple technique involving use of sand and activated charcoal barriers to effectively separate the shoot and root zones is described.
Zum Metabolismus von Phenylharnstoff‐Herbiziden VII. Metabolismusaufklärung und Bilanzierung des Verbleibs von Buturon‐14C nach Anwendung bei Winterweizen.
Authors: SCHUPHAN I. , EBING W. 
Published: July 2006

Zusammenfassung:Die radioaktive Bitanz zum Erntezcitpunkt ergab, daβ 89.1% der eingesetzten Radioaktivität wiedergefunden wurden. Davon waren 50.1% im Boden, 12.6% im Stroh, 3.7% in den Wurzeln, 1.3% in den Körnern nachweisbar. 16.2% wurden zu radioaktivem Kohlendioxid umgewandelt und fanden sich gasförmig oder im Kondenswasser niedergeschlagen. Die Radioaktivität im Pflanzenmaterial lag nur zu etwa 50% in extra hierbarer Form vor. In diesem Aktivitätsanteil bildeten stark polare Metaboliten die Hauptmenge, während die vier weniger polaren, identifizierten Buturonmetaboliten nur bis zu je 12% erreichten.
The influence of plant age on the movement of 2,4‐D and assimilates in wheat
Authors: OLUNUGA B. A. , LOVELL P. H. , SAGAR G. R. 
Published: July 2006

Summary:A quantitative study of the movement of 2,4‐D and assimilates was made using radiocarbon‐labelled materials. At the two‐three leaf stage of wheat (cv Koga II) 2,4‐D moved more slowly than assimilates, but the patterns of movement were very similar. At the five‐six leaf stage of the cereal there were differences between 2,4‐D and assimilates in the patterns of distribution from leaf 1 and from a leaf on a tiller. In both cases relatively less 2,4‐D moved into roots than would have been predicted from knowledge of assimilate movement. Total amounts of 2,4‐D reaching the roots did not differ significantly between growth stages but due to root growth, the concentration of radio‐activity in the roots fell.
Evolution of resistance to simazine in Senecio vulgaris L.
Authors: HOLLIDAY R. J. , PUTWAIN P. D. 
Published: July 2006

Summary:Fruits were collected from populations of S. vulgaris growing on commercial fruit farms and progenies were tested for susceptibility to simazine. The five least susceptible populations, which originated from sites where simazine had been applied annually for periods ranging from six to ten years, were subjected to two generations of artificial selection for simazine resistance. Two control populations which originated from unsprayed sites were treated similarly.One population originating from Malpas, Cheshire showed a significant response to selection. The simazine resistance of the other six populations was not improved by artificial selection. Selected progenies of the Malpas population were completely unaffected by simazine at 2.8 kg ha−1.The potential for evolution of resistance to simazine in S. vulgaris is discussed and the effects of ecological and genetic factors on the rate of evolution are assessed.
Uptake patterns of soil‐applied 45Ca and 32P in some legume species as influenced by differential trifluralin placement
Authors: O'DONOVAN J. T. , PRENDEVILLE G. N. 
Published: July 2006

Summary:The effect of localized placement of trifluralin on uptake patterns of soil‐applied 45Ca in vetch (Vicia sativa L.), pea (Pisum sativum L.) and soybean (Glycine max) and 32P in vetch and pea was investigated in two soil zones in the roots and in the shoot zone before and after plant emergence.When trifluralin was in the upper root zone severe inhibition of lateral roots occurred as well as a marked decrease in uptake of 45Ca and 32P from this zone. Root growth in the lower zone was unaffected, but uptake of 45Ca and 32P was slightly reduced. Compensatory adventitious root growth as well as a marked increase in uptake of 45Ca and 32P occurred in the shoot zone. Neither root growth nor uptake of 45Ca or 32P in the upper root zone were affected by the presence of trifluralin in the lower root region. When trifluralin was placed in the shoot zone after plant emergence, adven‐titious roots on the shoots were inhibited and uptake of 45Ca and 32P was reduced.