bluuebunny/crossref_metadata_2025 huggingface dataset:
Family History of Hypertension and Cardiovascular Changes During High and Low Affect Provocation
Authors: Lamensdorf Angela M. , Linden Wolfgang
Published: February 2007

The present study investigated whether subjects with a positive family history of hypertension would display differential responses in blood pressure and heart rate across different laboratory tasks. We also wanted to know whether subjects would display stable within‐subject responses across different laboratory tasks. Twenty‐three family history positive subjects and 23 with a negative family history participated in three tasks: 1) mental arithmetic, 2) a conversation about the weather (low affect task), and 3) a conversation about a recent upsetting, interpersonal event (high affect task). Positive family history was associated with elevated diastolic resting blood pressure and greater diastolic responsivity overall. For both groups, arithmetic was associated with the greatest heart rate changes, whereas the distressing conversation was accompanied by the greatest diastolic blood pressure response. Stability of cardiovascular activation across different tasks was present only for heart rate; it was weak for diastolic blood pressure, and completely absent for systolic blood pressure.
The relationship between trait hostility and cardiovascular reactivity: A quantitative review and analysis
Authors: SULS JERRY , WAN CHOI K.
Published: February 2007

Results of a series of meta‐analyses indicated that high and low scorers on most trait hostility measures do not consistently differ in blood pressure or heart rate reactivity to traditional laboratory stressors. The few significant effects were modest in size, and instances of hyporeactivity were found. When stressors were classified as provocative versus nonprovocative, in accord with Trait x Situation approaches, however, Potential for Hostility‐Interpersonal Style was predictive of exaggerated systolic and diastolic blood pressure responses and the Cook–Medley Hostility Inventory was predictive of diastolic blood pressure responses to provocative stressors. Hence, the next generation of studies of the hostility–reactivity hypothesis should emphasize interpersonal stressors. Alternative mechanisms for the disease consequences of hostility should also be examined, however, because the available evidence indicates that the hyperreactivity hypothesis is unlikely to furnish a complete explanation for the association between hostility and heart disease.
Conscious and nonconscious processes: An ERP index of an anticipatory response in a conditioning paradigm using visually masked stimuli
Authors: WONG PHILIP S. , SHEVRIN HOWARD , WILLIAMS WILLIAM J.
Published: February 2007

This study investigates the nonconscious elicitation of a previously conditioned response by using a differential conditioning paradigm with visually masked affectively valent facial schematics. Electrodermal (skin conductance response [SCR]) and brain (event‐related potential [ERP]) activity were main dependent measures. Following a preconditioning phase in which subjects viewed energy masked pleasant and unpleasant facial schematics, conditioning with an aversive shock was established to unmasked presentations of an unpleasant face in a partial factorial design. A postconditioning phase of masked presentations, when compared with the preconditioning phase, revealed how the conditional effect within awareness might affect the same stimuli when presented outside awareness. An adaptive staircase technique was used to establish individual threshold levels, which represented a methodological advance over procedures typically used in visual masking research. The results revealed that responses to the CS+ (unpleasant face) changed significantly in predicted directions from preconditioning to postconditioning phase when compared with responses to the CS− (pleasant face). The SCR results systematically replicated recent Ohman, Dimberg, and Esteves (1988) findings, with the pattern of responses resembling a resistance to extinction effect. A new finding emerged for the brain responses. For the CS+, distinct slow wave activity occurred just before the point at which the shock had been delivered in the conditioning phase; no such activity was found for the CS−. This slow wave activity is similar to what has been described by others as an expectancy wave. The results indicate that an anticipatory process, as indexed by different physiological systems, can be elicited entirely outside awareness. Implications are discussed in regard to the nature of conscious and nonconscious processes.
An ERP study on visual spatial priming with peripheral onsets
Authors: EIMER MARTIN
Published: February 2007

Visual event‐related potentials were measured for peripheral target stimuli that were preceded by a peripheral square. Targets appeared either at the same location as the square or in the opposite visual hemifield. In Experiment 1, 75% of the trials were same‐location trials, and in Experiment 2, same‐ and opposite‐location trials were equiprobable. The subject's overt response was dependent either on the identity or on the location of the target. In both experiments, opposite‐location targets elicited an enhanced PI at posterior electrodes ipsilateral to the position of the letter. This enhancement may be due to a sensory inhibition of same‐location targets. Same‐location targets elicited an enhanced negativity between 130 and 300 ms, with a first peak located parietally and a second peak broadly distributed over midline electrodes. This effect was larger in Experiment 1 than in Experiment 2 and is interpreted as enhanced processing of same‐location targets due to an attentional orienting process elicited by the peripheral square.
Signal attenuation as a function of integrator time constant and signal duration
Authors: BLUMENTHAL TERRY D.
Published: February 2007

In some laboratories, cyeblink electromyogram is rectified and smoothed before the analog signal is digitized. The relationship among the integrator time constant, the duration of the response, and the attenuation of the data was investigated by passing a number of signals at durations of 5, 10, 20, 50, and 100 ms into a contour‐following integrator (Coulbourn model S76–01), which first rectifies and then smooths (integrates) the signal. Integrator time constants of 10, 42, 70, 144, and 300 ms were used. The output of the integrator was sampled (1,000 Hz) and stored on a Macintosh SE computer. The integrator attenuated the signal, and the amount of attenuation increased as the duration of the signal decreased and as the time constant of the integrator increased. For brief inputs, the integrator does not charge fully, so only the early portion of the charge limb is present, and this early portion is the steepest part of the charge limb. Therefore, the longer the time constant, the less likely that small or brief responses will be detected.
Feasibility of intracranial near‐infrared optical scanning
Authors: GRATTON GABRIELE , MAIER JOHN S. , FABIANI MONICA , MANTULIN WILLIAM W. , GRATTON ENRICO
Published: February 2007

Light injected at a point on a surface of a scattering medium is emitted at the surface after traveling a quasisemicircular path deep into the medium. This phenomenon can be exploited to detect objects immersed in the medium from time‐resolved measurements of light intensity at the surface. Our experiments on model systems demonstrate that absorbing objects, surrounded by bone and other scattering material, can be detected. The technique yields surface images of absorbing objects submerged in a scattering medium. Images of the same phantoms inside the cavity of a skull can be obtained by the same technique.
Modulation of event‐related brain potentials by word repetition: Effects of local context
Authors: RUGG MICHAEL D. , DOYLE MICHAEL C. , HOLDSTOCK JULIET S.
Published: February 2007

In four experiments, event‐related brain potentials (ERPs) were evoked by visually presented word pairs in a task requiring responses to occasional target pairs. In Experiments 1 and 2, some pairs comprised items that had been presented previously. These repeated pairs consisted of words that had been paired together when first presented (same context condition) or words that had first been presented on consecutive trials (different context condition). ERP repetition effects were equivalent in the two conditions. In Experiment 3, same‐context repeats were contrasted with a condition in which a repeated word was paired with a new word. Only the same‐context pairs evoked a repetition effect. Experiment 4 showed that repetition effects to different‐ and same‐context repeats remained equivalent when first presentations of the members of different‐context pairs were separated by six intervening trials. We conclude that the ERP repetition effect shows little sensitivity to local context.
Brain event‐related potential correlates of overfocused attention in obsessive‐compulsive disorder
Authors: TOWEY JAMES P. , TENKE CRAIG E. , BRUDER GERARD E. , LEITE PAUL , FRIEDMAN DAVID , LIEBOWITZ MICHAEL , HOLLANDER ERIC
Published: February 2007

A hypothesis of overfocused attention in obsessive‐compulsive disorder was investigated by measuring auditory event‐related potentials (ERPs) during a selective attention task. Unmedicated patients (n= 18) with this disorder showed significantly larger attention‐related processing negativity (PN), with earlier onset and longer duration, than did normal controls (n= 15). In the N200 region (160–250 ms), PN was larger in patients with fewer nonspecific neurological soft signs. This task, however, did not yield any group differences in mismatch negativity (N2a) or classical N200 (N2b). P300 amplitudes for attended targets were smaller for patient than normal groups, but the reverse was true for P300 and positive slow wave amplitudes for unattended nontargets. Collectively, these ERP abnormalities suggest a misallocation of cognitive resources. Because of the importance of the frontal lobe in the control of selective attention, PN enhancement in patients with obsessive‐compulsive disorder may reflect hyperactivation of this region. This conceptualization is consistent with recent functional neuroimaging findings.
Suspense and surprise: On the relationship between expectancies and P3
Authors: VERLEGER ROLF , JASKOWSKI PIOTR , WAUSCHKUHN BERND
Published: February 2007

Few theories of the P3 component have emphasized the distinction between its parietal and frontocentral parts. This study used a new paradigm for testing the predictions that the parietal P3 is evoked by awaited stimuli (suspense) and the frontal P3 by unexpected stimuli (surprise). Subjects had to make simple responses whenever a yellow ring appeared. This signal appeared on the screen within a clock, most frequently when the pointer was at 12 o'clock (every 6s) but sometimes also at other times. The suspense process should therefore have its minimum shortly after 12 o'clock and then steadily increase until 12 o'clock, and the parietal P3 should accordingly be smallest with stimuli shortly after 12 o'clock, then gradually increase and be largest with 12 o'clock stimuli. Further, the stimuli presented at times other than 12 o'clock should evoke large frontal P3s because they were unexpected. The results confirmed parts of these predictions. A frontocentral and a parietocentral component could indeed be discerned. The frontal P3 was largest with non‐12 o'clock stimuli, whereas the parietal P3 was large with all stimuli. The parietal result was not predicted, but these results taken together pose more problems for the usual view, which assumes that the parietal P3 is evoked by unexpected stimuli, than for our assumption that the parietal P3 reflects suspense, and the frontocentral P3 reflects surprise. Generalizing to other paradigms, we assume that different topographies of P3 in different paradigms or in differnt groups of subjects might be due to different mixtures of these two components.
Nonconscious associative learning: Pavlovian conditioning of skin conductance responses to masked fear‐relevant facial stimuli
Authors: ESTEVES FRANCISCO , PARRA CRISTINA , DIMBERG ULF , ÖHMAN ARNE
Published: February 2007

We examined the possibility of nonconscious associative learning in a context of skin conductance conditioning, using emotional facial expressions as stimuli. In the first experiment, subjects were conditioned to a backwardly masked angry face that was followed by electric shock, with a masked happy face as the nonreinforced stimulus. In spite of the effectively masked conditioned stimuli, differential conditioned skin conductance responses were observed in a subsequent nonmasked extinction phase. This effect could not be attributed to differential sensitization or pseudo‐conditioning. In the second experiment, the differential responding during extinction was replicated with angry but not with happy faces as conditioned stimuli. It was concluded that with fear‐relevant facialexpressions as the conditioned stimulus, associative learning was possible even in conditions where the subjects remained unaware of the conditioned stimulus, associative learning was possible even in conditions where the subjects remained unaware of the conditioned stimulus and its relationship to the unconditioned stimulus.
Brain event‐related potentials to complex tones in depressed patients: Relations to perceptual asymmetry and clinical features
Authors: BRUDER GERARD E. , TENKE CRAIG E. , STEWART JONATHAN W. , TOWEY JAMES P. , LEITE PAUL , VOGLMAIER MARTINA , QUITKIN FREDERIC M.
Published: February 2007

Brain event‐related potentials (ERPs) to probe tones in a dichotic complex tone test were recorded from right‐handed depressed patients (n= 44) and normal subjects (n= 19) at homologous sites over left and right hemispheres (F3, F4; C3, C4; P3, P4; O1, O2). There were no differences between groups in N1 or P2 amplitude, but patients had smaller P3 amplitude than did normal subjects. Depressed patients failed to show either the left ear advantage or behavior‐related hemispheric asymmetry of P3 seen for normal subjects. Depressed patients also showed less differences in hemispheric asymmetry between same and different judgments. These findings indicate that the abnormal behavioral asymmetry for dichotic pitch discrimination in depressed patients reflects a reduction in hemispheric asymmetry and is related to relatively late stages of cognitive processing.
Spatial orienting and focused attention in attention deficit hyperactivity disorder
Authors: NOVAK GERALD P. , SOLANTO MARY , ABIKOFF HOWARD
Published: February 2007

Seventeen children with attention deficit disorder (ADHD) and 10 normal controls performed two tasks while event‐related potentials were recorded. ADHD subjects took part in two more sessions under methylphenidate (MP) or placebo. In the spatial orienting task, invalidly cued targets elicited a longer reaction time (RT) and a P3 that was longer in latency and greater in amplitude than did validly cued targets. Performance was similar for both groups, but the early portion of P3 (300–400 ms) was lower in amplitude for invalidly cued targets in ADHD subjects. MP increased accuracy without affecting RT and shortened P3 peak latency and increased the amplitude of its early portion. In the focused attention task, accuracy was greater for controls and MP, but there were no RT differenees. Attended stimuli elicited greater amplitude P1, N1, and P3 than did nonattended stimuli, but these measures were unaffected by diagnosis or medication.
The effect of lorazepam on memory and event‐related potentials in heavy and light social drinkers
Authors: NICHOLS JENNIFER M. , MARTIN FRANCES
Published: February 2007

To investigate the effects of heavy social drinking on sober cognitive processing, event‐related potentials were recorded from 13 heavy social drinkers and 13 light social drinkers in the presence and absence of a pharmacological challenge (i.e., lorazepam). Event‐related potentials were elicited by a task reuqiring continuous recognition memory for visually presented words. The heavy social drinkers exhibited shorter P2 latencies than the light in the task) versus “new” words. Lorazepam increased motor reaction time to correctly identified old words and produced a deficit in recognition memory only in the light social drinkers. Light social drinkers had an increased P300 latency anda larger P300 amplitude to new words in the lorazepam treatment. The differences in cognitive functioning evident between heavy and light social drinkers were reflected in event‐related potential deviations and appear to indicate a tolerance in heavy social drinkers to the effects of lorazepam.
A comparison of the electrophysiological effects of formal and repetition priming
Authors: Doyle Michael C. , Rugg Michael D. , Wells Tony
Published: February 2007

Three experiments investigated the electrophysiological consequences of repetition (e.g., scandal‐scandal, buple‐buple) and formal (e.g., scan‐scandal, bup‐buple) priming using words and nonwords. In each experiment, repetition and formal priming resulted in positive‐going shifts in the event‐related potential (ERP) that onset at approximately 200 ms poststimulus and were initially of similar magnitude. Subsequently, the repetition effect became larger than the formal priming effect. Although the word and nonword formal priming effects and the nonword repetition effects were greatest over midline and right hemisphere sites, the word repetition effects were greatest over the midline. It is suggested that the positive‐going shift seen in the repetition and formal priming conditions was a modulation of the well‐documented N400 component of the ERP. The topographic differences between the priming effects may have reflected differences in the nature of the representations to which cognitive operations are applied rather than differences in the nature of the operations themselves.
Lateralized startle probes in the study of emotion
Authors: Bradley Margaret M. , Cuthbert Bruce N. , Lang Peter J.
Published: February 2007

Two experiments are reported in which affective modulation of the startle reflex elicited by monaurally presented acoustic probes was further examined. An earlier study in our laboratory obtained significant modulation by effect for probes presented to the left ear, but no significant effect for probes presented to the right ear Experiment 1 replicated the procedures used in that experiment and obtained the same pattern of effects. Experiment 2 changed the presentation of monaural probes from a blocked to a mixed presentation and again obtained a similar pattern. Modulatory differences in reflex magnitude between pleasant and unpleasant stimuli were consistently large and reliable for reflexes elicited by left ear probes but weak and unreliable for reflexes elicited by right ear probes.
Ambulatory monitoring of the impedance cardiogram
Authors: Willemsen Gonneke H. M. , DeGeus Eco J. C. , Klaver Coert H. A. M. , VanDoornen Lorenz J. P. , Carrofl Douglas
Published: February 2007

The wowing need for more advanced ambulatory monitoring has led lo the development of an ambulatory monitor for impedance cardiography (VU‐AMD). This paper presents two studies addressing the validity of the VU‐AMD. In the first study, the cardiovascular responses of 25 subjects during various conditions were simultaneously recorded with the VU‐AMD and a standard laboratory impedance device. Correlations between the responses of the ambulatory and laboratory devices were high, both inter and intraindividually, except lot stroke volume and cardiac output during exercise In the second study, 26 subjects underwent 24‐hr monitoring with the VU‐AMD. The values obtained with the VU‐AMD were realistic and varied in a predictable way over activity and posture. It is concluded that the VU‐AMD is a valid device for the measurement of systolic time intervals in real‐life situations but its applicability for absolute stroke volume and cardiac output determination remains lo he established.
Affective learning: Awareness and aversion
Authors: HAMM ALFONS O. , VAITL DIETER
Published: February 2007

In two studies, we investigated the influence of aversive and nonaversive reinforcers on startle reactivity, visceral responses, and self‐report during Pavlovian conditioning. Furthermore, we assessed how awareness of the stimulus contingencies affect conditioned discrimination in the different response systems. Conditioned potentiation of the startle response was only observed in the context of aversive learning. Moreover, blink potentiation occurred without awareness of the relationship between the conditioned and unconditioned stimulus. In contrast, skin conductance conditioning was independent of the aversiveness of the reinforcer and was only obtained for those individuals who could correctly verbalize the stimulus contingency in a postconditioning recognition test. Cardiac responses varied with the task demands of the situation and covaried with individual response stereotypes.
P300 topography and modality effects from a single‐stimulus paradigm
Authors: POLICH JOHN , HEINE MICHELE R. D.
Published: February 2007

The P300 event‐related brain potential (ERP) was elicited with auditory and visual stimuli in two different tasks. The oddball paradigm presented both target and standard stimuli; the single‐stimulus paradigm presented a target but no standard stimulus, with the intertarget interval the same as that for the oddball condition. Target probability was .20 for the oddball task, with target stimuli occurring at the same temporal frequency in the single‐stimulus paradigm. Scalp topography was assessed with 15 electrode locations. P300 amplitude was larger and latency was longer for the oddball than for single‐stimulus procedure. P300 from auditory stimuli was smaller and shorter in latency than that from the visual stimuli, and both modalities showed similar but not identical scalp topographies. The findings suggest that the single‐stimulus paradigm may be useful in experimental and applied contexts that require very simple ERP task conditions.
Views on how the electrical activity that the brain generates reflects the functions of different language structures
Authors: KUTAS MARTA
Published: February 2007

Human language is what it is because of its function and its implementation. We are far from understanding how language comprehension is carried out by the human brain. This task can be made easier by considering that evidence for the what and how of language comes from the study of linguistics, psychology, and neuroscience. The approach outlined herein describes how these different sources of evidence can be combined in studies of written and spoken sentence processing by using a measure of the brain's electrical activity. The outcome is a more temporally precise view of the analysis of language structures in our minds and brains.
Maternal exposure to influenza and cold in pregnancy and electrodermal activity in offspring: The Mauritius study
Authors: VENABLES PETER H.
Published: February 2007

Data are in conflict concerning whether a mother's exposure to influenza in pregnancy gives rise to an increased probability that her offspring will develop schizophrenia. In Northern Hemisphere studies, exposure to influenza and cold tend to be confounded. The present study, carried out in Mauritius, examines the effect of maternal exposure to the virus and separately to cold on aspects of electrodermal activity that have been shown in other studies to be related to schizophrenia. The findings are that maternal exposure to influenza in the second and third trimesters gives rise to children who at the age of 3 years show electrodermal hyperresponsivity, whereas exposure to cold in the same periods gives rise to children who tend to be hyporesponsive. In both instances, exposure tends to produce lower levels of tonic activity than in those not exposed to the virus or to cold.
Prepulse inhibition decreases as startle reactivity habituates
Authors: BLUMENTHAL TERRY D.
Published: February 2007

In the present study, I investigated the effect of stimulus repetition on human startle eyeblink reflex inhibition (PPI) by a prepulse. Participants were assigned to one of three groups (n= 14 each). in which they received 18 trials of (a) noise startle stimuli presented alone or preceded by 1000‐Hz tone prepulses, (b) startle stimuli presented alone, or (c) prepulses presented alone. All participants then received 18 more trials of startle stimuli presented alone or preceded by 1000‐Hz tone prepulses, followed by 6 trials of startle stimuli presented alone or preceded by 2000‐Hz tone prepulses. As trials progressed, startle eyeblink electromyogram magnitude habituated and PPI decreased. PPI was not affected by the repeated presentation of the prepulses alone but decreased with the repeated presentation of the startle stimulus alone. Changes in the frequency of the prepulse had no significant effect on PPI. These data suggest that the reduction of PPI that is seen across trials is not due to habituation of the prepulse but is related to startle reactivity in control trials, which is reduced by habituation.
The effect of emotional and attentional processes on blink startle modulation and on electrodermal responses
Authors: LIPP OTTMAR V. , SIDDLE DAVID A. T. , DALL PATRICIA J.
Published: February 2007

Emotional accounts of startle modulation predict that startle is facilitated if elicited during aversive foreground stimuli. Attentional accounts hold that startle is enhanced if startle‐eliciting stimulus and foreground stimulus are in the same modality. Visual and acoustic foreground stimuli and acoustic startle probes were employed in aversive differential conditioning and in a stimulus discrimination task. Differential conditioning was evident in electrodermal responses and blink latency shortening in both modalities, but effects on magnitude facilitation were found only for visual stimuli. In the discrimination task, skin conductance responses, blink latency shortening, and blink magnitude facilitation were larger during to‐be‐attended stimuli regardless of stimulus modality. The present results support the notion that attention and emotion can affect blink startle modulation during foreground stimuli.
The acidity of Welsh soils
Authors: Thompson T. R. E. , Loveland P. J.
Published: February 2007

Abstract. The pH of soil surface horizons in Wales ranges from 3.5 to 7.5 and is significantly higher on agricultural land than under either rough grazing, unenclosed grassland or woodland. Sufficient information exists to map broad classes of soil pH. Rough grazing and woodland sites are concentrated on soil types which are naturally very acid. In Wales, such soils are found on the main mountain ranges and show up clearly on the map of pH. Their acidity is the result of an interrelationship between soil, climate and vegetation. However, afforestation, particularly with coniferous species, appears to lower the pH of the underlying soil. There is a trend in agricultural soils towards lower pH under a moister climate.
A method to measure the susceptibility of pasture soils to poaching by cattle
Authors: Scholefield D. , Hall D.M.
Published: February 2007

Abstract. A new method of measuring susceptibility to poaching is described, based on the concept that poaching is caused by a progressive loss of soil strength during repeated treading in wet weather. Susceptibility was measured by the rate of loss of strength in response to concurrent treading and irrigation at standard rates. The pressures exerted on the ground by a walking dairy cow were simulated by a purpose‐built penetrometer, whilst water was applied via a network of plastic pipes fitted with syringe needles. Measurements were performed on four pasture soils having a range of clay contents and compared in relation to a mechanism proposed for the process. The results show susceptibility to be a property not wholly determined by the clay content of the soil, but suggest that it is influenced by bulk density and the strength of the sward, which will van, according to weather and pasture management.
Application of drainage theory in the field
Authors: Towner G.D. , Youngs E.G.
Published: February 2007

Abstract. The prediction of water‐table levels from groundwater theory for a drainage system in a uniform homogeneous soil was tested in an existing field system. Specially designed meters recorded water‐table heights and drain discharge with time. A comprehensive hydraulic conductivity survey was made below the water table.

The results agreed with theory for water‐table heights up to about 300 mm above the mean drain level. The drainage above that level was larger than predicted, either because of an increased hydraulic conductivity (which could have been produced by subsoiling the previous year and would not have been picked up by die hydraulic conductivity measurements), or because of the presence of an older shallower lateral drainage system, broken and blocked, that was discovered during the work.

Attention is drawn to the inadequacies of dip‐wells for monitoring rapid changes in water‐table levels and to the problem of sample size in hydraulic conductivity measurements, which if too small can lead to apparent variability.
Upland afforestation: influences on stream hydrology and chemistry
Authors: Hornung M. , Newson M.D.
Published: February 2007

Abstract. Afforestation in the British uplands can lead to changes in the hydrology, sediment load and chemistry of streams. These changes may affect water resource management costs, stream biota and the health of fisheries. Some of the changes can be related to specific phases of the forest management cycle, e.g. site preparation, fertilization, felling; modifications in management practice can limit their impact. Other changes in water yield and chemistry seem to have complex origins in forest‐atmosphere and forest‐soil interactions; these are more difficult to counteract.
Computerized soil data used in agricultural water planning, Denmark
Authors: Madsen Henrik Breuning
Published: February 2007

Abstract. A nationwide soil database system has been established containing soil maps, analytical data, and soil classification. The system has been widely used in agricultural planning at county and national level. This paper describes the basic data used for the soil database system, and the exploitation of this system in agricultural water planning. The principles for calculating the irrigation need at county level are given and also those for nationwide mapping of the potential need for drainage. Mapping of potentially acid sulphate soils, which has given rise to legislation on drainage of wetlands, is described, and the future use of the soil database system in agricultural water planning is discussed.
Management of soil water for wheat production in Western Australia
Authors: Hamblin Ann , Tennant D. , Perry M.W.
Published: February 2007

Abstract. Spring wheats are sown in autumn and mature under conditions of spring water deficits in Western Australia. While grain yields are very small (averaging 1.05t ha‐1), water‐use efficiencies (WUE) of crops grown with good management compare favourably with the rest of Australia at 10 kg grain ha‐1 mm‐1. Major water loss, calculated at an average 40% of growing‐season rainfall, occurs through evaporation from the soil surface, and in some years significant losses also occur through deep drainage on sandy soils. Evaporation losses can be reduced by stubble retention and adding gypsum to improve filtration on structurally unstable, fine‐textured soils. More general increases in crop water use occur through all agronomic factors which result in rapid and uniform plant cover as early as possible after break of season. This includes adequate fertilization, weed control and narrow row‐width. Wheat crops sown after pasture and grain legumes consistently outyield all‐cereal rotations.
Crop and soil response to subsoil loosening, deep incorporation of phosphorus and potassium fertilizer and subsequent soil management on a range of soil types.: Part 2: Soil structural conditions
Authors: Soane G.C. , Godwin R.J. , Marks MJ. , Spoor G.
Published: February 2007

Abstract. In a series of experiments on 16 sites both a power‐driven rotary‐tine Wye Double Digger and a rigid tine winged subsoiler produced significant subsoil loosening and fissuring. The Double Digger consistently produced the greatest clod breakdown together with the least soil bulk densities and cone penetration resistances. Management strategies after loosening had an important influence on the longevity of the loosening effect. The rate of recompaction was least with controlled traffic and bed systems and increased with random traffic and with the growing of root crops. No significant differences in crop response were monitored between the two loosening treatments, yield response depending largely on the extent of moisture stress experienced by the crop. Loosening on silty soils reduced yields in wet seasons and this was associated with soil structural instability. Visual soil profile examination is necessary to support bulk density and cone penetration resistance measurements when assessing soil compaction.
Land evaluation of basaltic terrain under semi‐arid to mediterranean conditions in the Golan Heights
Authors: Singer Arieh
Published: February 2007

Abstract. Soils derived from basalt bordering the northern Jordan Valley have developed under semi‐arid to humid Mediterranean conditions and belong to two major soil orders: Vertisols in the drier south and Alfisols (Brown and Red Mediterranean soils) in the more humid north. Major limitations on land use of the vertisols are low hydraulic conductivity, slow infiltration and strong susceptibility to erosion by water. Crops growing on basalt‐derived soil also suffer from phosphorus deficiency, though the soils contain much inorganic phosphorus. The natural vegetation is mainly herbaceous and grows well even under intensive and continuous grazing. The land is best used for pasture wherever limitations restrict other uses.
Potassium reserves in a forested, acid upland soil and the effect on them of clear‐felling versus whole‐tree harvesting
Authors: Goulding K.W.T. , Stevens P.A.
Published: February 2007

Abstract. The experiment conducted jointly by the Forestry Commission (FC) and the Institute of Terrestrial Ecology (ITE) at Beddgelert Forest, North Wales, studies the effect of conventional clear‐felling (CF) and whole‐tree harvesting (WTH) of Sitka spruce (Picea sitchensis) on the local ecosystem and on the future productivity of forestry at the site. Bulked soil samples were taken from Block 2 of the experiment just before felling in 1984 and two years later in 1986. Sub‐samples from the horizons Ah, E and B+C were analysed for exchangeable and short‐ and long‐term reserves of K using Ca‐resin and strong acid extraction procedures. The flux of K through the soil profile after both CF and WTH resulted in a small increase in exchangeable K throughout the profile after both treatments, but in a loss of short‐term reserves from the surface Ah horizons of both and an overall loss of these after WTH. The nutrient flux down‐slope through the Ah horizon could result in differential nutrient deficiency in future. The data suggest that exchangeable and short‐term reserves of K will support about two further cycles of conifers, with either CF or WTH, but that long‐term reserves are likely to be released quickly enough to meet the needs of such a slow‐growing crop; these would support about 30 cycles. Other nutrients, such as Ca or P, may prove to be more limiting than K.
Predicting deep drainage in the soil from soil properties and rainfall
Authors: Shaw R.J.
Published: February 2007

Abstract. Simple predictions of deep drainage in the soil profile are often required for preliminary planning of land management where the cost of direct measurement is not warranted. Soil hydraulic conductivity and drainage of water below the root zone can be related to the salt content at the bottom of the root zone, assuming steady‐state balances of water and salt. A physically based empirical model uses readily measured soil properties to predict the quantity of drainage below the root zone under varying regimes of water management and shows a good relationship with ponded infiltration rate.
Direct drilling compared with ploughing for winter wheat grown continuously and the effects of subsoiling
Authors: Hodgson D.R. , Hipps N.A. , Braim M.A.
Published: February 2007

Abstract. Direct drilling was compared with mouldboard ploughing on a sandy clay loam using winter wheat as the test crop for a period of four years (1978/79 to 1981/82). The effect of short‐ and long‐term sequences of direct‐drilling on grain yield from 1981/85 was also investigated and in 1983/84 and 1984/85 the effect of soil loosening by a slant‐legged subsoiler, the‘Paraplow'. The range in annual mean yields was 7.19 to 9.32 t ha‐1. There were no significant differences in grain yield between direct‐drilling and ploughing except in 1979 when direct‐drilled wheat yielded 0.60 t ha‐1 more than wheat after ploughing. The number of years the land had been direct‐drilled had no effect on grain yield.

Using a slant‐legged subsoiler on direct‐drilled land significantly reduced cone resistance and increased root density, but these effects were variable across the working width of the implement. Subsoiling did not increase yield in 1983/84, and in 1984/85 it reduced yield by 0.45 t ha‐1.

Long‐term direct drilling of winter wheat on the Tickenham soil series is unlikely to result in a loss of yield provided straw is burnt and grass weeds are controlled.
Soils at risk of accelerated erosion in England and Wales
Authors: Evans R.
Published: February 2007

Abstract. The 296 soil associations of the National Soil Map of England and Wales are placed into five categories of erosion risk. These are based on land use, landform and soil properties and take into account the extent of erosion in the uplands, and its frequency, extent and rates in the lowlands. Erosion of arable land is by water or wind, but in the uplands frost action and disturbance by sheep are also important. A large proportion of arable England (36%) is at moderate to very high risk of erosion, including much of the better drained and more easily worked land, especially sandy soils. In the uplands thin soils or deep peats are most at risk. If land use changes, because of increasing intensification of agriculture or in response to climatic changes, many soil associations will become more at risk of erosion.
Chalk and chalk debris as a medium for plant growth, with particular reference to Channel Tunnel spoil
Authors: Burnham C.P.
Published: February 2007

Abstract. Four lithological types of chalk are recognized. Normal white chalk has 34–50% porosity, nearly all of which holds water conventionally‘available’to plants. Hard chalk and grey chalk have less porosity and available water; chalk marl has very little available water. Significant capillary rise from below the root zone can be expected in normal white chalk only, and is not halted by fragmentation. Chalk has little N and usually little P. Only grey chalk and chalk marl have much ettractable K and Mg. These also slake, impeding roots. Thus, fertilized plants tolerant of high pH can grow well on normal white chalk debris, but on raw chalk marl, e.g. Channel Tunnel spoil, they need irrigation. Interesting plants volunteer on chalk debris, even on slaked chalk marl by the sea.
Factors responsible for soil erosion hazard in submontane Punjab, India
Authors: Kukal S.S. , Sur H.S. , Gill S.S.
Published: February 2007

Abstract. Various factors of soil erosion (erodibility of the soil, slope of the land and nature of the plant cover) were studied in a representative area of submontane Punjab. In the north‐eastern part of the area, slope steepness, slope length, convexo‐concave and concave slope patterns and sparse vegetation were the dominant factors governing erosion hazard. In the central and lower south‐western part of the area, high soil credibility and sparse vegetation were the most important factors.

Rill erosion was positively correlated (r= 0.87) with slope steepness. The erodibility of the soil was strongly correlated (r= 0.98) with amounts of silt + very fine sand.

In the area with steeper slopes, the lower segments of transects were prone to more erosion because of high credibility. Slope shapes such as convexo‐concave and concave could result in sloughing and greater erosion hazard if not properly protected. Slopes facing southwest were more prone to erosion than others because of more solar energy, greater aridity, less vegetation and concave shape.
Land degradation mapping by remote sensing in the arid region of India
Authors: Raina Pramila , Joshi D.C. , Kolarkar A.S.
Published: February 2007

Abstract. In arid regions of India, cultivation of marginal areas and overgrazing of pastures have resulted in degradation of land. Accelerated wind erosion on sandy surfaces and water erosion on the shallow soils of piedmont areas are both common. Landsat Thematic Mapper sub‐scenes have been used to map the type, extent and degree of degradation. In an area of over 5000 km2, 42% was affected by wind erosion and 50% by accelerated water erosion. A quarter of the whole area needs urgent attention for soil conservation.
Rates of soil erosion on arable fields in Britain: quantitative data from caesium‐137 measurements
Authors: Quine T. A. , Walling D. E.
Published: February 2007

Abstract. Despite a growing awareness that erosion on arable land in Britain is a potential hazard to long‐term productivity, there is still only limited information on the rates involved, particularly long‐term values. Use of the caesium‐137 (137Cs) technique to study soil erosion within arable fields on various soil types at 13 locations in southern Britain has yielded retrospective measurements of the long‐term (c. 30 years) rates of soil loss and the patterns of soil redistribution within the study fields. The range of long‐term rates of net soil loss extends from 0.61 per hectare per year on clay soils in Bedfordshire to 10.5 t per hectare per year on brown sands in Nottinghamshire. The measured rates are compared with other published data for similar soil types and land use, and the implications for long‐term productivity and potential environmental impacts are considered.
Seasonal variation in the aggregate stability of downland soils
Authors: Blackman J. D.
Published: February 2007

Abstract. Seasonal variation in the aggregate stability of chalk downland soils on the South Downs, East Sussex, UK, was studied using two measures of aggregate stability: water stable aggregation by wet sieving and dispersibility by a turbidimetric determination. Aggregate stability and organic carbon content were assessed on a monthly basis at 20 sites over a 19‐month period.

Results indicated considerable variation in water stable aggregation over the time period studied but little variation in dispersibility. There were differences between sites mainly reflecting differences in organic carbon content. Soils with more organic carbon showed less seasonal variation in aggregate stability than soils with small amounts of organic carbon. This suggests that in less organic soils organic materials, mainly microbial in origin, play an important role in forming stable aggregates, though their effect is transient.
Soil in land suitability evaluation: an example with oil palm in Nigeria
Authors: Ogunkunle A. O.
Published: February 2007

Abstract. The land of the Nigerian Institute for Oil Palm Research (NIFOR) main station in southern Nigeria was evaluated for suitability for oil palm cultivation by the FAO system using data from 12 pedons representing four soil series. The results indicate that although the climatic factors are near optimum and more than half of the pedons were potentially moderately (S2) or highly (S1) suitable, the current suitability is marginal (S3). The major limitations were soil fertility (K mole fraction, CEC) and particle size. In this and similar environments good soil management is required before substantial improvements in oil palm production can be achieved.
The effects of lead shot deposition on soils and crops at a clay pigeon shooting site in northern England
Authors: Mellor A. , McCartney C.
Published: February 2007

Abstract. The impact of lead shot on soils and crops was examined at a clay pigeon shooting site in northern England. Topsoil cores were collected along a 300 m transect from the shooting range, and the numbers of lead shot pellets per soil core, total and ‘plant‐available’(0.5m acetic acid extractable) lead concentrations, organic matter content, pH and cation exchange capacity were determined. The number of oilseed rape plants and their stem diameters were recorded in 1 m2 quadrats placed at the soil sampling locations. Total and ‘plant‐available’ lead concentrations in the soil were most but plant numbers per m2 and mean stem diameters were least in the area of greatest lead shot deposition. Total lead concentrations in the soil commonly exceeded 5000 mg/kg; these are considerably greater than threshold ‘trigger’ concentrations proposed by the Department of the Environment, above which soils are considered to be contaminated and warrant further investigation. Concentrations of lead in the oilseed rape plants themselves were also largest in the area of most intense lead shot deposition; in root samples the lead concentration exceeded 400 mg/kg. The management and remediation of contaminated soils at the clay pigeon shooting site are discussed.
Soil pH decline in relation to rotation, tillage, stubble retention and nitrogen fertilizer in S.E. Australia
Authors: Heenan D.P. , Taylor A.C.
Published: February 2007

Abstract. The decline in topsoil (0–0.1 m) pH (CaCl2) over 11 years (1979–90) was measured in a rotation, tillage, stubble and nitrogen fertilizer experiment on a Chromic Luvisol at Wagga Wagga in S.E. Australia. The rotations consisted of annual wheat cropping (WW) with and without nitrogen fertilizer (100 kg N/ha/year), alternating lupin‐wheat (LW) and subterranean clover‐wheat (CW). The initial mean pH at the site was 4.9 and the experiment was preceded by subterranean clover‐based pasture for most of the previous 19 years. An initial rapid decline in soil pH under all treatments over the first 8–9 years was followed by a 2–3 year period when no further decline was detected. The annual rate of pH decline over the first 8–9 years varied from 0.06 for WW to 0.09 units for WW with added N fertilizer. Apparent steady‐state for WW after 11 years was approximately 0.5 pH units higher than for WW with added N fertilizer. There was no difference between CW and LW in the rate of decline or in the apparent steady‐state reached. Six years’ stubble burning in a LW rotation promoted a slightly higher pH than where stubble was retained. However, there was no significant effect of tillage in either LW or CW rotations. By 1990 the addition of N fertilizer to WW had increased the concentration of exchangeable aluminium by 100% and of manganese by 24%. The inclusion of a legume in the rotation increased the concentration of aluminium but did not affect manganese. However, burning stubble in the LW rotation slightly decreased manganese concentrations.