bluuebunny/crossref_metadata_2025_split huggingface dataset:
Differences between soil solutions obtained from rhizosphere and non‐rhizosphere soils by water displacement and soil centrifugation
Authors: LORENZ S.E. , HAMON R.E. , McGRATH S.P. 
Published: July 2006

SummarySoil solution was obtained from potted rhizosphere or non‐rhizosphere soils by water displacement or soil centrifugation. The pH of the displaced solutions was lower than that of bulk soils when solutions were obtained from non‐rhizosphere soil, although it increased as plants grew. This increase probably reflected true changes in rhizosphere pH, generated by the uptake by plants of N03‐N. In contrast, the pH of soil centrifugates was usually close to that of the bulk soils, implying that buffering by colloids had occurred during sampling. Concentrations of elements in solutions from non‐rhizosphere soil were similar for both methods when soils were incubated at ambient pCO2. However, when non‐rhizosphere soils were incubated at elevated pCO2, displacement solutions had lower pH values, and much larger concentrations of elements, compared to soil centrifugates.Comparison of mass flow of elements versus actual plant uptake showed that Ca and Mg accumulated, while K, Zn and Cd were depleted from the rhizosphere. Displacement solutions showed this accumulation or depletion of the elements more clearly than soil centrifugates. These differences were attributed to the fact that, at constant soil moisture, the rhizosphere developed mainly in larger pores, which were sampled by displacement. With centrifugation, a mixture of pore sizes was sampled, so that rhizosphere solution was only obtained when all of the soil had become rhizosphere.Soil centrifugates obtained after 22 days of growth also contained higher concentrations of organic carbon than displacement solutions, indicating contamination due to the disruption of roots and/or micro‐organisms. We conclude that water displacement is suitable for sampling solution from light to medium textured rhizosphere or non‐rhizosphere soils and that soil centrifugation is only of limited suitability.
Lysimeter study of the fate of nitrogen in animal urine returns to irrigated pasture
Authors: FRASE P.M. , CAMERON K.C. , SHERLOCK R.R. 
Published: July 2006

SummaryThe fate of 15N‐labelled synthetic urine (50 g N m−2) applied to an irrigated pasture soil was studied using large undisturbed monolith lysimeters (800 mm diameter × 1200 mm deep). Over a period of 1 year, the pasture plants recovered the largest fraction of the applied 15N (43%) and approximately 20% of the applied 15N still remained in the soil, the majority of which was found in the topsoil (0–20 cm). Although the experiment was conducted under relatively intense rainfall and irrigation conditions, only 8% of the applied 15N was found to have leached below 1200 mm after 1 year. During this time, the average peak concentration of nitrate in the leachate reached 42 mg NO3−‐N dm−3. The amount of nitrogen (N) lost by the process of denitrification was calculated as 28% of the applied 15N. This large loss of N to the atmosphere was attributed to the wet soil conditions which prevailed.
Land‐use effects on the composition of organic matter in particle‐size separates of soil: I. Lignin and carbohydrate signature
Authors: GUGGENBERGER G. , CHRISTENSEN B.T. , ZECH W. 
Published: July 2006

SummarySoil from Eutrochrept A horizons under long‐term spruce forest (Sf), mixed deciduous forest (Df), permanent grassland (Gp) and arable rotation (Ar) was fractionated according to particle size and analysed for contents of C, N, lignin‐derived phenols and carbohydrates.Whole soil from Sf, Df, Gp and Ar contained 84, 59, 73 and 25 g C kg−1 soil, respectively. For all sites, the C content declined and C/N ratio increased in the order: clay (<2 μm), silt (2–20 μm), sand (20–2000 μm). Clay and silt were significantly lower in C in Ar than in Sf, Df and Gp, C associated with sand being substantially lower under arable rotation.The yield of lignin‐derived phenols decreased and carboxyl functionality and methoxyl demethylation of lignin derivatives increased with decreasing particle size, indicating a progressive lignin alteration. Whole soil from Sf and Gp was substantially higher in vanillyl (V), syringyl (S) and cinnamyl (C) units (VSC) than soil from Df and Ar. Compared to whole soil, clay was depleted and sand enriched in VSC. Only sand appeared to be affected significantly by land use. Sand from Ar and Df was more enriched in VSC than sand from Gp and Sf.Whole soil carbohydrates decreased in the order: Gp>Ar>Df>Sf. Sand‐ and clay‐sized separates were enriched in carbohydrates compared to silt. Carbohydrates in sand were mainly of plant origin whereas microbially‐derived sugars accounted for a larger proportion in the clay. Compared to Sf, Df and Gp, clay from Ar was enriched and sand depleted in microbial sugars.Lignin and carbohydrate distribution patterns indicate that organic matter was in a more advanced stage of decomposition in the sand separates from forest than from agricultural A horizons. The forest soils also show a higher degree of oxidative changes in lignin associated with clay. In contrast, differences between silt from the four A horizons were small.
The role of tillage in soil redistribution on hillslopes
Authors: GOVERS G. , VANDAELE K. , DESMET P. , POESEN J. , BUNTE K. 
Published: July 2006

SummarySoil tillage is usually considered as a process having only an indirect influence on soil erosion. This paper describes the results of field experiments carried out with a mouldboard and a chisel plough showing that an important net downslope soil movement can be associated with soil tillage. Available experimental evidence suggests that the soil redistribution by tillage can be described by a diffusion‐type equation, which allows the intensity of the process to be characterized by a single number, which may be called the diffusion constant. The experimentally determined values of the diffusion constant vary between 100 and 400 kg m−1 a−1. This implies that erosion and sedimentation rates associated with tillage may be more important than those associated with water erosion on much of the hilly arable land in western Europe. A comparison of recent hillslope evolution with model simulation results corroborates this conclusion. Therefore, tillage should be considered as a soil degradation process per se, rather than a process which makes the soil more sensitive to erosion.
A STUDY OF THE COMPETITION BETWEEN BARLEY AND OATS AS INFLUENCED BY BARLEY SEEDRATE, NITROGEN LEVEL AND BARBAN TREATMENT
Authors: PFEIFFER R. K. , HOLMES H. M. 
Published: July 2006

Summary. The object of the work described in this paper was to obtain information on the relationship between the effects of crop competition and barban treatment on oats growing in another cereal. The work was carried out on barley cross‐drilled with cultivated oats. Variation in crop competition was obtained by using different barley seed‐rates and nitrogen levels. Increasing the seedrate of barley without applying barban resulted in a reduction of the initial oat population. This reduction applied to weight of individual shoots, number of shoots and panicles per unit area and number of spikelets per panicle. The application of barban at selective rates gave an independent reduction of oats of the order of 80%. This value proved almost constant at each seedrate of barley. Crop competition and barban accordingly seem to art independently and their effects appear to be simply additive. The barley fresh weights per unit area increased substantially when oat competition was reduced by barban treatment. The highest increase occurred on the plots with the lowest barley seedrate in spite of the fact that these plots still appeared infested with oats at harvest time. Nitrogen application stimulated the growth of barley and oats to a similar degree and did not in consequence lead to a selective suppression of oats.Etude de l'influence de la densité du Semis, du taux de fertilisation azotée et du traitement au barbane, sur la concurrence entre une Orge et une Avoine
UNTERSUCHUNGEN ÜBER DIE GEGENSEITIGE BEEINFLUSSUNG VON KULTURPFLANZEN UND UNKRÄUTERN IN WASSERKULTUR
Authors: RADEMACHER B. , KOLB F. , BÖRNER H. 
Published: July 2006

Zusammenfassung. Es wurden Untersuchungen über die gegenseitige Beeinflussung von Kulurpflanzen und Uukräutern in Wasserkultur durchgeführt. Hierbei wurde eine Methodik verwendet, die es gestattete, die Ursachen einer gegenseitigen Beeinflussung auf den Wurzelbereich zu beschränken und gleichzeitig die Wirkung einiger Konkurrenz‐faktoren (z.B. Licht, Raum) ausz.uschalten. Von insgesamt 57 untersuchten Pflanzen‐kombinationen (Ergebnisse s. Tab. 1‐4) zeigten etwa ein Drittel keine gesicherten Symptome einer gegenseitigen Beeinflussung. Bei allen anderen Versuchen war ein mehr oder weniger ausgeprágter Hemm‐ bzw. Förderungseffekt festzustellen. Die Ursache dieser Erscheinung konnte in einigen Fallen als Náhrstoffkonkurrenz (Nr. 5, 6, 7, 23, 44d. Tabellen) erkannt werden, wáhrend bei anderen Versuchen (Nr. 12, 13, 15, 18, 23, 45, 46) mit der Beteiligung allelopathischer Faktoren (Abgabe organischer Verbin‐dungen aus lebenden und abgestorbenen Wurzelzellen) gerechnet werden muss. Die Wachstumshemmung bzw.‐ förderung war in einigen Fällen dann besonders deutlich (Nr. 46, 47, 51), wenn dem einen Partner durch Vorkultur ein gewisser Entwicklungs‐vorsprung gegeben wurde. Obwohl einige der vorliegenden Ergebnisse mit Befunden aus der Praxis gut übereinstimmen (Nr. 12, 13, 18), kann man aus naheliegenden Gründen (Abbau von Wurzelstoffen durch Mikroorganismen, Absorptionsverhältnisse im Boden usw.) die in Wasserkultur erzielten Resultate nicht unmittelbar auf die natürlichen Verhältnisse übertragen, Um jedoch den möglichen Ursachen einer gegenseitigen Beeinflussung von Kulturpflanzen und Unkräutern überhaupt einmal náher zu kommen, ist cine getrennte Untersuchung der in Frage kommenden Faktoren unumgánglich.Experiments on the interaction between cultivated plants and weeds in water‐culture
CONTROLLED INTERFERENCE WITH NATURAL POPULATIONS OF PLANTAGO LANCEOLATA, P. MAJOR AND P. MEDIA
Authors: SAGAR G. R. , HARPER JOHN L. 
Published: July 2006

Summary. An experiment was made to determine the effect of the removal of grasses on the behaviour of populations of Plantago lanceolata, P. media and P. major in three grassland habitats. Treatments included the addition of seed of all three species to the existing vegetation. The grasses were removed by treatment with 2,2‐dichloropropionic acid (dalapon), a herbicide selective against the Gramineae. The chemical appears to be slightly toxic to the Plantago species at the dose used (12 Ib/ac a.e.). The removal of the grasses was followed by a marked increase in the plantain populations shown both in counts of the numbers of plants and seedlings and in increased seed output per unit area. Deliberate sowing of seed into the habitats in autumn resulted in increased numbers of seedlings in the following spring, particularly in those plots where the grasses had been removed. Species of Plantago not occurring naturally in the communities were frequently established by sowing seed, if the grasses had been removed, but not otherwise. The overall results of the experiment suggest that in two of the communities the grasses played an important role in determining the presence or absence of particular Plantagn species and also in controlling the size of the existing plantain populations. The experiment is discussed in the wider context of population control in plants.Tentative de modification de populations naturelles de Plantago lanceolata, P. major et P. media.
THE CONTROL OF WEEDS IN SPRING CEREALS WITH MCPA, MCPB AND 2,4‐DB
Authors: EVANS S. A. 
Published: July 2006

Summary. Eighteen experiments were carried out over a period of 4 years jointly by the National Agricultural Advisory Service and the Agricultural Research Council Unit of Experimental Agronomy to compare the effects of spraying spring cereals with MCPA, MCPB, 2,4‐DB and mixtures of MCPA and MCPB, at two different times. The first applications was made before the cereal crop had reached the five‐leaf stage and when it was judged that most of the weeds had germinated. The second application was after the crop had reached the five‐leaf stage, which is the time normally recommended in Britain for the application of MCPA to spring wheat or spring barley. The earlier applications produced better crop yields and gave a better control of weeds except where conditions for spraying were unsatisfactory or where a considerable number of weeds germinated subsequently. Mild deformity of the ears of the crop occurred in some experiments following early applications of MCPA, otherwise there were no marked differences in the effect on the crop of the different herbicides at the doses used; the dose of MCPA was less than that of the other herbicides. In view of these results and the lower cost of MCPA, it is concluded that MCPA applied early is the most efficient of the treatments tested except where the risk of malformed ears occurring is not acceptable.Le désherbage dans les céréales de printemps avec le MCPA, le MCPB, et le 2,4‐DB
HEMMUNG DER HILLREAKTION DURCH HERBIZIDE*
Authors: EXER B. 
Published: July 2006

Zusammenfassung. In dieser Arbeit haben wir den Einfluss des Herbizides Simazin auf die Hillreaktion untersucht, wobei DPN (Diphosphopyridinnukleotid) und Janusgrün als Wasserstoffakzeptoren verwendet wurden. Die Hemmung der Hillreaktion durch Simazin ist bei verschiedener Lichitiniensität, sowie bei verschiedenen Chloroplasten‐ und Wasserstoffakzeptorkonzentrationen studiert worden. Die Hemmung der Hillreaktion durch Simazin ist von der eingesetzten DPN‐Menge unabhängig. Durch Erhöhung der Lichtintensität wird die Hemmwirkung von Simazin auf die DPN‐Reduktion abgeschwächt; im gleichen Sinne wirkt auch eine Erhöhung der Chloroplastenkonzentration. Die Bildung von Safranin durch reduktive Spaltung von Janusgrün durch belichtete Chloroplasten ist von der Menge des eingesetzten Janusgrüns abhängig, wobei ein Optimum auftritt. Je höher die Janusgrünkonzentration gewählt wird, um so stärker wird die Hillreaktion durch Simazin gehemmt. Dieser Effekt ist darauf zurückzuführen, dass sowohl Janusgrün, als auch Safranin bei höheren Konzentrationen selbst als Inhibitoren wirken, was mit der DPN‐Methode gezeigt werden konnte. Auf Grund dieser Ergebnisse haben wir die Methodik zur Messung der Hillreaktion mit DPN oder Janusgrün als Wasserstoffakzeptoren soweit ausgearbeitet, dass sie sich zur vergleichenden Messung der Hemmwirkung verschiedener Herbizide eignet. Wird die prozentuale Hemmung der Hillreaktion durch eine Substanz gegen den Antilogarithmus ihrer Konzentration aufgetragen, so erhält man eine Gerade im Bereich zwischen 15 und 90%; die Konzentration für eine 50%ige Hemmung lässt sich somit leicht interpolieren.Inhibition of the Hill‐reaction by a herbicide
AN ASSEMBLY FOR THE CONTINUOUS RECORDING OF CO2 EXCHANGE AND TRANSPIRATION OF WHOLE PLANTS
Authors: VAN OORSCHOT J. L. P. , BELKSMA M. 
Published: July 2006

Summary. Photosynthesis, respiration and transpiration of whole platns are continuously recorded with the assembly described. An infra‐red gas analyser is used for photosynthesis and respiration measurements, while for transpiration data psychrometers are employed, Air and leaf temperatures as well as light intensity are recorded. The assimilation chamber is constructed in such a way that whole platns of various plant species can be investigated under constant conditions of CO2 content of the air and air humidity. Some experiments with simazine and monuron are described.Un appareil pour enregistrer continuellement l'échange de CO2 et la transpiration des plantes entiéres
THE MOVEMENT OF LABELLED 2,4‐D IN YOUNG BARLEY PLANTS
Authors: VAN DER ZWEEP W. 
Published: July 2006

Summary. After the 4‐ or 5‐leaf stage in young barley plants, there is a decrease in the translocation of 2,4‐D from the leaves to the root system. It is shown that there is no relation between this phenomenon and ear initiation, which occurs at this stage of development. Movement of 2,4‐D out of leaves of the tiller in the axils of the 1st and 2nd leaves was also shown to be very small. There is some evidence for a‘block’in the movement of 2,4‐D in established grass plants.La migration du 2,4‐D marqué dans l'orge
ACTION DE QUELQUES HERBICIDES SUR LA MORPHOGENESE DU RAY‐GRASS D'ITALIE
Authors: LEROUX R. , FAIVRE‐DUPAIGRE R. , LONGCHAMP R. 
Published: July 2006

Résumé. Le Ray‐grass d'Italic (Lolium italicum A. Braun.), variété‘Mayenne’, traité au stade du tallage par des produits à basc de 2,4‐D, MCPA et MCPB, présente toute une série de modifications des tiges et des épis, lorsquc ces herbicides soni appliqués à des concentrations de l à 10 kg à l'hectare (exprimées en acidc libre). Les tiges deviennent rameuses par suite d'un tallage aberrant et certains nœuds et entre‐nœuds sont courbes, les courbures des entre‐nœuds étant inverses de celles des nœuds. Les altérations des épis concernent le rachis et les épillets. Le rachis peut être bifurqué ou trifurqué, sinucux, allongé ou raccourci, helicoidal, courbc enfin parce que retenu dans la gainc de la dernière feuille. Les épillets anormaux touchent le rachis par une face, sont attachés au même niveau ou au même point, sont encore pédicellés, composés, réduits, voire stériles. Ces différents types d'anomalies. notés séparément ou simultanément sur la même plante, la même tige, parfois sur le méme épi, sont rapprochés des modifications observées chez d'autres graminées fourragères et des résultats classiques obtenus sur les céréales, á la suite de traitements réalisés avec des désherbants de, nature identique.Der Einfluss einiger Herbizide auf die morphologische Formbildung von Italienischem Raygras
THE INFLUENCE OF IRRIGATION, FERTILIZING AND MCPA ON THE COMPETITION BETWEEN SPRING CEREALS AND WEEDS
Authors: SUOMELA H. , PAATELA J. 
Published: July 2006

Summary. The average air‐dry yield of weeds on fallow plots was about four times as large (2660 kg/ha) as the yield of weeds which developed among spring cereal crops (740 kg/ha). Application of fertilizers increased the number of weeds and their average weight on both irrigated and non‐irrigated plots. Treatment with MCPA reduced the weed yield to 36% on fallow plots and to 26% on weedy cereal plots. It was more effective on fertilized plots than on unfertilized plots, but irrigation made little difference to its effectiveness. The space left by the destroyed weeds was mainly occupied by Agropyron repens. Oats were better able to compete with weeds than were wheat and barley. On unfertilized and non‐irrigated plots spraying with MCPA (1‐26 kg/ha) at the beginning of shooting significantly reduced the yields of weed‐free barley. The yields of sprayed oats and wheat were also below the yields from the unsprayed although the reductions were not significant at the 5% level. However, on a number of fertilized and irrigated plots, both weedy and hand‐weeded, on which the plants had better growing conditions, MCPA resulted in a significant increase in the grain yield of barley and oats.Influence de l'irrigation, de la fertilisation et du MCPA sur la compétition entre céréales de printemps et mauvaises herbes
FURTHER INVESTIGATIONS INTO THE FIELD USE OF A MIXTURE OF ENDOTHAL AND PROPHAM FOR PRE‐EMERGENCE APPLICATION TO SUGAR BEET
Authors: CALDICOTT J. J. B. 
Published: July 2006

Summary. Pre‐emergence applications on a wide range of mineral soil types with a proprietary formulation of an endothal/propham mixture established a relationship between the amounts of coarse sand and clay in a soil and the rate of use of the chemical required for optimum results. The effectiveness of a given dose for any one soil type was found to be dependent on adequate rainfall between time of application and weed emergence. The minimum rainfall required varied with the date of the application. A wide range of seedling weeds was adequately controlled and treated areas which exhibited a good control of weeds at emergence were found to be still weed‐free as long as 14 weeks after treatment.Etudes sur l'application en pré‐émergence aux betteraves d'un mélange endothal/propham
SOME ASPECTS OF THE USE OF BARBAN FOR WILD OAT CONTROL IN WINTER WHEAT
Authors: HOLMES H. M. , PFEIFFER R. K. 
Published: July 2006

Summary. A study of the emergence and development of Avena fatua in winter wheat showed that after the mild winter of 1960/61 autumn‐germinated wild oats constituted a far more serious weed problem than spring‐germinated plants. It was concluded that the application of barban should be timed in relation to these autumn‐germinated plants. As an extension of their work on spring cereals, the authors investigated the effect of barban on the yield ratio of winter wheat and cultivated winter oats grown as a mixture. A reduction in the oats fraction as a result of barban treatment was accompanied by an increase in wheat giving a total yield which was almost the same as untreated. Experimental data are also presented on the occurrence, and significance of an interesting variation in crop tolerance during the winter. No obvious correlation was found between increased crop sensitivity and development stage or temperature. The capacity of the crop to recover was found to be high.Quelques données sur l'utilisation du barbane dans la lutte contre la folle avoine dans le blé d'hiver
UUBER DEN ZUSAMMENHANG ZWISCHEN KONSTITUTION UND HERBIZIDER WIRKSAMKEIT BEI CYCLOALIPHATISCHEN HARNSTOFFVERBINDUNGEN*
Authors: SCHEUERER G. , FISCHER A. 
Published: July 2006

Zusammenfassung. Substituierte N‐Cycloalkylharnstoffverbindungen wurden auf ihre Verwendung zur Bekämpfung unerwünschten Pflanzenwuchses untersucht. Die Herbizidwirksamkeit ist abhängig von der Grösse des Cycloalkylringes und der Art der Ringsubstituenten, sowie von deren Stellung und sterischen Anordnung am Ring. Das Wirkungsoptimum liegt bei 8 Ringkohlenstoffatomen. Die wirksamen Vertreter dieser Klasse eignen sich zur Bekämpfung von Unkrautwuchs in Hackfrucht‐ und Sonderkulturen.Relationship between the structure and herbicidal properties of N‐cyclo‐alkyl‐urea
THE CONTROL OF WEEDS IN POTATOES BY PREEMERGENCE APPLICATION OF HERBICIDES
Authors: STEPHENS R. J. 
Published: July 2006

Summary. Trials in 1959, 1960 and 1961 failed to show significant differences in yield between potatoes (Solanum tuberosum L.) of three varieties receiving from seven to nine separate tractnr cultivations and similar potatoes in which the weeds were well controlled by pre‐emergence applications of a mixture of dinoseb(6.0 lb/ac)*and dalapon (2.5‐5.0 lb/ac), With less effective herbicide treatments. including simazinc and 2,4‐DES, there were significant reductions in yield.Preliminary taint tests in 1959 on cooked tubers suggested that slight tainting might have been caused by one of the treatments, but tests on potato crisps made from the 1959 and 1960 crops were completely inconclusive. Tubers from all the treatments in the 1959 and 1960 trials sprouted normally in the spring after harvest.Le désherbage des pommes de terre par des herbicides de pré‐émergence