bluuebunny/crossref_metadata_2025_split huggingface dataset:
The influence of temperature and water table position on carbon dioxide and methane emissions from laboratory columns of peatland soils
Authors: MOORE T. R. , DALVA M. 
Published: July 2006

SUMMARYLaboratory columns (80 cm long, 10 cm diameter) of peat were constructed from samples collected from a subarctic fen, a temperate bog and a temperate swamp. Temperature and water table position were manipulated to establish their influence on emissions of CO2 and CH4 from the columns. A factorial design experiment revealed significant (P < 0.05) differences in emission of these gases related to peat type, temperature and water table position, as well as an interaction between temperature and water table. Emissions of CO2 and CH4 at 23°C were an average of 2.4 and 6.6 times larger, respectively, than those at 10°C. Compared to emissions when the columns were saturated, water table at a depth of 40 cm increased CO2 fluxes by an average of 4.3 times and decreased CH4 emissions by an average of 5.0 times. There were significant temporal variations in gas emissions during the 6‐week experiment, presumably related to variations in microbial populations and substrate availability. Using columns with static water table depths of 0, 10, 20, 40 and 60 cm, CO2 emissions showed a positive, linear relation with depth, whereas CH4 emissions revealed a negative, logarithmic relation with depth. Lowering and then raising the water table from the peat surface to a depth of 50 cm revealed weak evidence of hysteresis in CO2 emissions between the falling and rising water table limbs. Hysteresis (falling > rising limb) was very pronounced for CH4 emissions, attributed to a release of CH4 stored in porewater and a lag in the development of anaerobic conditions and methanogenesis on the rising limb. Decreases in atmospheric pressure were correlated with abnormally large emissions of CO2 and CH4 on the falling limb. Peat slurries incubated in flasks revealed few differences between the three peat types in the rates of CO2 production under aerobic and anaerobic conditions. There were, however, major differences between peat types in the rates of CH4 consumption under aerobic incubation conditions and CH4 production under anaerobic conditions (bog > fen > swamp), which explain the differences in response of the peat types in the column experiment.
A device for determining the sorptivity of soil aggregates
Authors: LEEDS‐HARRISON P.B. , YOUNGS E.G. , UDDIN B. 
Published: July 2006

SummaryA device that infiltrated water over a small circular surface area having a radius ranging between 1.45 mm and 2.5 mm was used to measure the sorptivity of initially air‐dry aggregates of size greater than 20 mm. The small infiltration area caused the water uptake to be dominated by capillarity that allowed the use of a simple formula to obtain the sorptivity from the steady‐state flow rate that occurred very early after the start of imbibition. The results of measurements of sorptivity made on a fine sand agreed with those obtained from measurements on one‐dimensional water infiltration into columns of the sand. Sorptivity measurements on stabilized aggregates of a clay soil and on air‐dried field aggregates of a clay soil were easily made. The simplicity and rapidity of the method allowed measurements to be conveniently replicated.
Retention of vanadium (V) by three Finnish mineral soils
Authors: MIKKONEN A. , TUMMAVUORI J. 
Published: July 2006

SummaryRetention of V(V) by three Finnish mineral soils from 10−4m and 10−5m sodium vanadate solutions was investigated at room temperature in the pH range 2.3–7.5. In adsorption experiments, 0.02 m KCl was used as ionic medium, and the samples were left to equilibrate for 72 h. The solid: solution ration was 1:100 (m: v). Maximum adsorption occurred at pH ∼4, where 70–80% of the added V (350–400 μg g−1 from 10−4m solution and 35–40 μg g−1 from 10−5m solution) was retained by each soil. Retention was significant even at pH 6, where adsorption of a similar anion, molybdate, is negligible. Desorption of the retained V was measured by adding 50.0 cm3 of 0.02 M KCl into weighed soil samples and shaking for 17 h in a mechanical stirrer. Only a minor part of retained V could be removed from each soil by the KCl treatment.Retention of different ionic species of V from 10−5m solution is approximated using values of log K obtained from the literature. In these calculations, kaolin is used as a reference material.
Coupled diffusion and oxidation of ferrous iron in soils: III. Further development of the model and experimental testing
Authors: KIRK G.J.D. , SOLIVAS J.L. 
Published: July 2006

SummaryEquations are developed to predict the distribution of Fe2+between solid and solution phases in a reduced soil undergoing oxidation at different pHs, based on cation‐exchange equilibria and electrical neutrality in the solid and solution. The equations satisfactorily explained experimental results. They are incorporated in the model of Fe2+diffusion and oxidation developed in Part II, and the model is also extended to allow for O2consumption in processes other than Fe2+oxidation. The resultant predictions are tested against measured profiles of Fe(II), Fe(III) and pH in cylinders of reduced soil exposed to O2at one end. When oxidation rate constants measured in stirred soil suspensions were used to run the model, the predicted rates of O2consumption were too great and the spread of the oxidation front too small. Satisfactory agreement was achieved for oxidation rate constant values about one‐eighth of those measured in the stirred suspensions. The findings are consistent with the rate of Fe2+oxidation in soil being controlled by access of O2to Fe2+sorption sites, as suggested in Part I. The revised model allows a study of the effects of Fe2+oxidation on the mobility of other cations in reduced soils, e.g. nutrient cations in the rice rhizosphere. Fez+ oxidation and the accompanying acidification may greatly impede cation mobility in reduced soils.
THE EFFECT OF DEPTH OF BURYING AND FREQUENCY OF CULTIVATION ON SURVIVAL AND GERMINATION OF SEEDS OF WILD OATS (AVENA FATUA L. AND AVENA LUDOVICIANA DUR.)
Authors: THURSTON J. M. 
Published: July 2006

Summary. Seeds of Avena fatua and A. ludoviciana were sown at a depth of 15 cm or mixed into the top 5 cm of soil in small field‐plots at Rothamsted and subjected to 5 different regimes of depth and frequency of cultivation for 3 years, after which all plots were dug to 15 cm in spring and autumn for a further 4 years. Seedlings were counted and no plants were allowed to produce seeds. After 7 years, soil‐samples showed that very few intact seeds of A. fatua and none of A. ludoviciana remained, although less than 20% of the seeds sown had produced seedlings. Laboratory tests after 4 to 8 years’dry slorage showed seeds of both species to be viable. The maximum survival of viable seeds, estimated by seedling‐emergence, was 61 months for A. fatua and 33 months for A. Indoviciana. Seeds of A. fatua survived slightly longer at 15 cm than in the top 5 cm of soil. Survival of A. ludoviciana was less affected by depth and cultivation, except that birds ate some shallow‐sown spikelets in the first fortnight after sowing. A. fatua germinated in spring and autumn, and A. tudoviciana in winter, irrespective of age of seed and cultivation of soil. Frozen soil delayed emergence of A. ludoviciana seedlings lor varying periods between December and March. Seedlings of A. ludoviciana were slightly more winter‐hardy than A. fatua. More seedlings of A. fatua appeared in the second spring than at any other time, but 80% of the seedlings of A. ludoviciana appeared in the first autumn and winter. Effets de la profondeur d'enfouissement des graines et de la fréquence des façons culturalles sur la longévité et la germination des semences de Folle‐Avoine (Avena fatua L. et A. ludoviciana Dur.)
THE CONTROL OF RANUNCULUS REPENS (L.) IN RASPBERRIES
Authors: ROBINSON D. W. 
Published: July 2006

Summary. Experiments conducted in Northern Ireland between 1956 and 1960 show that Ranunculus repens may be controlled by MCPA‐salt or ‐ester applied in November or December. These compounds are more effective than salt or ester formulations of 2,4‐D and salt formulations of MCPB and 2,4‐DB. Three varieties of raspberry were uninjured when a salt formulation of MCPA was applied during December at 2.2 kg/ha to the same plots for three successive years. Five other varieties were uninjured after one year's treatment. Wetting the dormant canes to run‐off with MCPA‐salt at 2000 ppm caused no injury but, in one experiment, MCPA‐salt at 4.5 kg/ha reduced the number of shoots the following season. The margin of safety is not high but, in the absence of any alternative chemical means of controlling R. repens in raspberries, a late November or December application of MCPA‐salt at 2.2 kg/ha is recommended in Northern Ireland where this weed is prevalent. In two trials, raspberries appeared to be slightly more tolerant of 2,4‐D than of MCPA but in general, control of R. repens with winter applications of 2,4‐D was inadequate except where the weeds were young or active.La lutte contre Ranunculus repens L. dans les framboisiers
THE RELATIONSHIP BETWEEN THE HERBICIDAL EFFECT OF 2,6‐DICHLOROBENZONITRILE AND ITS PERSISTENCE IN THE SOIL
Authors: BARNSLEY G. E. , ROSHER P. H. 
Published: July 2006

Summary. A series of experiments with 2,6‐dichlorobenzonitrile is described. It is demonstrated that 2,6‐DBN is highly phytotoxic when applied as a soil drench or preemergence spray in the greenhouse, but measurement of crop and weed responses in the field, accompanied by quantitative assessment of the chemical residues in the soil, indicates that the persistence of 2,6‐DBN following surface application is short under both tropical and temperate (winter) conditions. It is, however, extended from a few days to several weeks if the chemical is incorporated into the soil immediately after application. Under tropical conditions the effect of 4 lb/ac applied to the surface is roughly equated to 2 lb/ac immediately watered‐in, 1.5 lb/ac immediately raked‐in, or 1 lb/ac both watered‐ and raked‐in, and a delay of 4 hours between application and incorporation is shown to reduce the effectiveness of the chemical by about half. The lack of persistence of 2,6‐DBN when applied to the soil surface, and the modifying influence of soil incorporation and watering is attributed to its high vapour pressure (5 × I0−4 mm Hg at 20° C) and its relatively low solubility in water (20 ppm at 25° C).Le rapporl entre l'activité herbicide du 2,6‐dichlorobenzonitrile et sa persistance dans le sol
THE REACTION OF TRIFOLIUM REPENS (L.) IN GRASSLAND TO 2,4‐D, MCPA AND MIXTURES OF 2,4‐D AND MCPB
Authors: ELLIOTT J. G. 
Published: July 2006

Summary. Eight experiments were carried out on a range of pasture lypes under different management and in different years to lest the reaction of white clover (Trifolium repens in grasstand to doses of up to 4 lb/ac of the herbicides MCPA‐sodium or‐potassium and 2,4‐D‐amine. The initial effect of the treatments was to reduce the amount of dover in the sward, the size of the reduction varying greatly from field to field for any one dose. In general, the higher the dose, the more severe was the depression of the clover 1 month after spraying. Both herbicides at 2 and 4 lb/ac caused substantial depressions on some of the fields. The growth of the treated clover was examined during the year following spraying. The ability of the clover to recover from the initial depression varied considerably in the different fields; on some, recovery started in the year of spraying and on others in the following year. Quick recovery was usually associated with a high initial resistance but there were fields in which the clover showed contrasting rates of recovery following similar depressions. The experiments produced no clear‐cut evidence as to why the initial resistance and speed of recovery varied in different fields. In one experiment the effects of MCPB‐sodium and 2,4‐D‐amine on white clover were compared separately and in a series of mixtures. An examination made 6 weeks after spraying showed that MCPB at up to 8 lb/ac had no significant effect on the clover, whereas 2,4‐D at 1 lb/ac caused a 22% reduction. Mixtures containing up to 0.37 lb 2,4‐D and up to 6 lb MCPB caused no reduction while those containing 0.75 lb 2,4‐D and 4 lb MCPB were not significantly different from 1 lb 2,4‐D alone. Reaction de Trifolium repens (L.) en prairie au 2,4‐D, au MCPA, et aux mélanges de1, 2,4‐D et de MCPB
CONTROL OF SONCHUS ARVENSIS (L.) WITH CHEMICALS
Authors: VIDME T. 
Published: July 2006

Summary. Pot experiments concerning the control of Sonchus arvensis with chemicals showed that the time of application of MCPA or 2,4‐D has a dominant influence on the results obtained. Foliage applications at late rosette to early bud stage gave considerably better effects than did earlier or later applications as assessed by the. weight of roots, this assessment being considered the most reliable for final effects. Increasing the rates from 1 to 3 kg/ha was of less significance than the time of application. A good wetting ability of the spray solution is also essential for an effective control of this weed, which has very waxy leaves. The addition of a wetting agent to aqueous solutions of various salts of 2,4‐D had a great and significant influence on the effects. This was not the case with 2,4‐D acid in Carbowax. When wetter was added, there was no difference in the effects of the sodium, ammonium and triethanolamine salts. The latter were also slightly more effective than MCPA. 2,4‐D‐ester was much more effective than MCPA by foliage application. When the chemicals were applied to the roots through sub‐irrigation pipes, however, MCPA was at least as effective as 2,4‐D‐ester. The maximum effect by this method of application was obtained at a somewhat later stage of development than by foliage application. By foliage application of MCPA and dinoseb or DNOC at various rates used alone or in mixture, an antagonism between the growth regulator and the contact herbicides was demonstrated as regards the reduction in root weight of S. arvensis. The scorching effects of dinitro compounds were, on the contrary, increased when applied in combination with MCPA. Amitrole at rates of 5, 7.5 and 10 kg/ha applied at late rosette stage gave a complete kill of S. arvensis.La destruction du Sonchus arvensis L. à l'aide de produits chimiques
CHEMICAL WEED CONTROL IN SPRING‐SOWN BROAD BEANS
Authors: ROBERTS H. A. , WILSON B. J. 
Published: July 2006

Summary. During the period 1956‐61, twelve replicated field experiments were conducted to determine the response of spring‐sown broad beans (Vicia faba L.) and annual weeds to various pre‐ and post‐emergence herbicides. On a sandy loam, the best results were given by pre‐emergence applications of simazine 0.75 lb/ac, trietazine 1.5 lb/ac, chlorpropham 1 lb+diuron 0.2 lb/ac or dinoseb‐amine 4 lb/ac. Amiben proved insufficiently selective, while chlorpropham+fenuron caused greater crop injury than the corresponding mixture with diuron. Post‐emergence application of dinoseb‐amine was less satisfactory than the best of the pre‐emergence treatments.Le désherbage chimique des fèves semées au printemps
THE EFFECTS OF MALEIC HYDRAZIDE AND 2,4‐DICHLOROPHENOXYACETIC ACID ON ROADSIDE VEGETATION
Authors: YEMM E. W. , WILLIS A. J. 
Published: July 2006

Summary. Observations have been made on the effects of maleic hydrazide (MH) and 2,4‐dichlorophenoxyacetic acid (2,4‐D), used singly or as a combined spray, on the vegetation of roadside verges, over a period of 3‐4 years (1958‐61). Each year, replicate plots were sprayed in spring, and assessments of growth and floristic composition of the vegetation, which was dominated by grasses, were usually made on three occasions. Treatment with MH, used singly, resulted in a general suppression of growth and flowering, particularly of the grasses. Well‐marked changes in the composition of the sward were attributable to MH, notably the decline of tufted forms, e.g. Arrhenatherum elatius, Dactylis glomerata, and the rise to dominance of the rhizomatous grasses. These changes were associated with a progressive increase of some dicotyledonous plants, although this was effectively prevented by the combined spray of MH and 2,4‐D. Two of the commonest weeds, Anthriscus sylvestris and Heracleum sphondylium, were almost eliminated from plots treated with this combined spray for 3 successive years; a low sward, fairly free from dicotyledons and dominated by Poa rather than Festuca, usually resulted. Treatment with 2,4‐D alone, had relatively little effect on growth, flowering and proportion of the different grasses, but there was a reduction in the weed population.Les effets de l'hydrazide maléique et de l'acide 2,4‐dichlorophénoxyacétique sur la végetation au bord d'une route
PRELIMINARY OBSERVATIONS ON THE BREAKDOWN OF 3‐AMINO‐l,2,4‐TRIAZOLE IN SOIL
Authors: RIEPMA P. 
Published: July 2006

Summary. The breakdown of amitrole has been studied on different soil types and at two temperatures. It is shown by use of soil sterilization and of microbiological toxicants, that amitrole is broken down microbiologically. Increase in soil organic matter and in temperature up to 30° C both increase the rapidity of breakdown.Premières observations sur la décomposition du 3‐amino‐1,2,4‐triazole dans le sol
THE EFFECT OF 4,6‐DINITRO‐O‐CRESOL* (DNOC) ON GROWTH, DEVELOPMENT AND YIELD OF WINTER RYE (SECALE CEREALE L.)
Authors: BRUINSMA J. 
Published: July 2006

Summary. The spraying with DNOC as a herbicide in a young crop of winter rye results in an increased grain yield, even in weed‐free trials. In order to trace the sequence of reactions by which treatment in winter affects the yield next summer, growth, development and yield of treated and untreated plants were examined in a single weed‐free experiment which included the study of several seed rates.As a result of the DNOC treatment, vegetative growth was retarded at first, but later the treated plants recovered and surpassed the control plants in fresh and dry weight. Since their dry matter percentage was somewhat lower and their nitrogen content a little higher, the crop appeared both more vigorous and more youthful. Leaf blade area and chlorophyll content of leaves and culms were increased and chlorophyll breakdown at ripening was delayed.No effect could be observed on the rate of development of the young spike, but heading, flowering and ripening were retarded.Yield increase on the DNOC‐treated plots was 10% on an average. The analysis reveals that on these plots 3% more culms were formed, each of which bore 5% more kernels; the average kernel weight was unaffected. The increase in ear density can be ascribed to the more luxuriant vegetative growth, while the kernel weight per car is correlated with the nitrogen content of the culm.It is concluded that the yield increase is due to a stronger vegetative growth together with a prolonged period of generative development.Effets d'un traitement au DNOC sur la croissance, le développement el le rendement d'un seigle d'hiver
STUDIES ON THE TRANSLOCATION IN AGROPYRON REPENS OF 14C‐LABELLED 2,2‐DICHLOROPROPIONIC ACID
Authors: McINTYRK G. I. 
Published: July 2006

Summary. Previous findings suggested that the translocation in Agropyron repens of 2,2‐dichloropropionic acid (dalapon) may be considerably affected by the transpiration rate. This relationship has been studied further in the present investigation using 14C‐labelled material and autoradiography.It was found that when dalapon was applied to the leaves and the treated plants were placed in darkness a reduction in the transpiration rate of ca. 90% was associated with a marked increase in the amount of dalapon translocation into the roots and tillers. The evidence provided by the autoradiographs was confirmed by a quantitative assay of the 14C present in the roots. It was also found, however, that translocation was not appreciably affected either by a 50% reduction in the light intensity or when the transpiration rate was reduced by placing the plaints under conditions of high humidity in the light or by the application of white petroleum jelly to the leaves. An alternative hypothesis, namely that the effect of darkness on the movement of the herbicide might be due to changes induced in the normal pattern of assimilate translocation was also investigated but was not supported by the results obtained. Further experimentss, in which various parts of the treated shoot were placed in the dark, suggested that the effect of darkness on the translocation of dalapon is exerted primarily on the treated leaf itself. Etudes sur to migration dans Agropyron repens de l'acide 2,2‐dichloropropionique marqué avec 14C
1‐PHENYL‐4‐AMINO‐5‐CHLOR‐PYRIDAZON‐6* (PCA) ALS EIN NEUES RüBENHERBIZID
Authors: FISCHER A. 
Published: July 2006

Zusammenfassung. Bei unseren Arbeiten zur Entwicklung neuer Rübenherbizide fiel die Sloffgruppe der Phenylpyridazone als besonders wirksam auf. Es wurden bisher über 500 Pyridazon‐Dcrivate geprüft. Bei diesen Untersuchungen zeigte l‐Phenyl‐4‐amino‐5‐chlor‐pyridazon‐G (PCA) die besten herbiziden Eigenschaften. PCA besitzt sowohl im Vor‐ als auch im Nachauflauf‐Verfahren bei Aufwandmengen von 1‐3 kg/ha Wirkstoff eine genügende Selektivität gegenüber Zucker‐ und Futterrüben. Die Nachwirkungszeit von PCA in lehmigem Sandboden ist kürzer als diejenige von OMU, CMU und Simazin. Nach einer Behandlung mit 2 kg/ha PCA kann eine Neueinsaat nach 8‐10 Wochen ohne Gefahr für die Kulturpflanzen erfolgen. Die herbizide Wirkung von PCA umfasst die meisten in Rübenkulturen vorkommenden Samenunkräuter. Schwierig bekämpfbar sind Avena fatua und einzelne Vicia‐Arten. überhaupt nicht bekämpfbar sind sämtliche Wurzelunkräuter. PCA ermöglicht eine Unkrautbekämpfung in Rüben ohne Rücksicht auf deren Entwicklungszustand. Günstiger Spritztermin: Keimblattstadium der Unkräuter. Mögliche Rübensch aUden sind abhängig vom Wetter zur Zeit der Spritzung. Am günstigsten sind windstilles Wetter, bedeckt Himmel, Temperaturen bis etwa 22°C sowie eine relative Luftfeuchtigkeit von 40‐70%. Die Unkrautwirkung von PCA wird durch geringen Zusatz von OMU im Vorauflauf‐Verfahren eindeutig gesteigert. Die Bekämpfung grösserer Unkräuter (2.‐4. Laubblattstadium) im Nachauflauf‐Verfahren mit 1‐3 kg/ha PCA kann durch Zusatz von 100‐150 kg/ha NaNO3 verbessert werden.5‐amino‐4‐chloro‐2,3‐dihydro‐3‐oxo‐1‐phenylpyridazone as a new herbicide for sugar beet
THE EFFECTS OF SUB‐LETHAL DOSES OF MCPA ON THE MORPHOLOGY AND YIELD OF VEGETABLE CROPS
Authors: WAY J. M. 
Published: July 2006

Summary. The effect of sub‐lethal doses of MCPA‐sodium on the morphology, growth and yield of carrots and parsnips was studied in twenty replicated field experiments. Slight epinasty was produced in carrots by doses as low as 0.002 lb/ac a.e., but formative effects were not usually seen below 0.01 lb/ac. Crop weight was only reduced by doses greater than 0.1 lb/ac, but abnormalities rendered a proportion of the roots unmarketable at doses below 0.05 lb/ac. Small plants were sometimes killed by 0.3 lb/ac, but larger plants survived treatment with up to 0.5 lb/ac. Tests on carrots which were unmarketable on grounds of appearance failed to reveal any effect of MCPA on flavour, sweetness or texture of the roots. The effects of MCPA on parsnips were similar to those on carrots, but the expression of injury symptoms was generally less marked.Les effets de doses sub‐létales de MCPA sur la morphologie et le rendement des cultures légumières III. Carottes et panais