bluuebunny/crossref_metadata_2025 huggingface dataset:
The role of the right hemisphere in the physiological and cognitive components of emotional processing
Authors: Spence Sarah , Shapiro David , Zaidel Eran
Published: February 2007

Right hemisphere specialization for emotional processing was investigated using behavioral and psychophysiological methods, Fifty undergraduates were shown slides depicting negative emotional and neutral scenes briefly lateralized to the right or left cerebral hemispheres and asked to categorize each as emotional or neutral. Pulse volume and heart rate (HR) measured physiological processing and reaction time measured cognitive processing. The largest vasoconstriction responses and HR deceleration were obtained for emotional items in the right hemisphere. However, reaction time failed to show right hemisphere superiority in perceptual/cognitive processing, demonstrating instead slowest responses to emotional stimuli presented to the right hemisphere together with evidence for left hemisphere competence. Selective right hemispheric activation in autonomic responses, combined with the lack of right hemisphere specialization in the cognitive task, suggests that the physiological response system rather than the perceptual/cognitive system is the locus of the right hemisphere superiority for emotion.
Picture media and emotion: Effects of a sustained affective context
Authors: BRADLEY MARGARET M. , CUTHBERT BRUCE N. , LANG PETER J.
Published: February 2007

Pleasant, neutral, or unpleasant pictures were presented in a continuous series, and the effects of repetitive exposure to pictures of the same affective valence were assessed in somatic (corrugator electromyographic [EMG] activity) and visceral (heart rate and skin conductance) systems. Probe stimuli (startle or reaction time probes) were presented to index emotional and attentional concomitants of processing. Affective discrimination was maintained across time in all response systems, and sensitization was found for the corrugator EMG response. Responses to reaction time probes indexed differences in attentional allocation as a function of cognitive and affective variables in this paradigm. Taken together, the data suggest that presentation of a series of affective pictures of similar valence produces emotional reactions that are either maintained or sensitized across the temporal intervals used here but that do not habituate.
Is an apple a fruit? Semantic relatedness as reflected by psychophysiological responsivity
Authors: BEN‐SHAKHAR GERSHON , FROST RAM , GATI ITAMAR , KRESH YIFAT
Published: February 2007

In the present study, we investigated orienting response generalization across various types of semantically related stimuli. Four experiments, based on a modified version of the guilty knowledge technique, were designed to examine whether semantic relations based on abstract features are reflected by electrodermal responsivity. No generalization across coordinates was obtained, but a moderate degree of generalization was demonstrated between a word and its superordinate category (e.g., table‐furniture) and between a word and its synonym. Complete generalization occurred from a verbal label of an object to its pictorial representation, and vice versa. These results are compatible with our proposal that partial identification of the test stimulus as relevant is a necessary condition for generalization in the guilty knowledge technique.
The varying time courses of attentional and affective modulation of the startle eyeblink reflex
Authors: VANMAN ERIC J. , BOEHMELT ANDREAS H. , DAWSON MICHAEL E. , SCHELL ANNE M.
Published: February 2007

In previous research on modulation of the startle eyeblink reflex, emotional effects have been demonstrated only at late probe positions, whereas attentional effects have been found at both early and late positions but only when the prepulses were affectively neutral. In Experiment 1, participants viewed emotionally valenced pictures and were instructed to attend to the duration of half of the slides. Affective modulation of the startle eyeblink occurred at long lead intervals, but attentional modulation also occurred late. In Experiment 2, participants viewed the same slides used in Experiment 1 but were instructed to attend to the duration of only the positive or the negative slides. Affective modulation occurred at both early and late probe positions, whereas attentional effects occurred only following slide offset. Early (250 ms) affective modification of startle eyeblink has not been previously reported. These results suggest that the time courses of emotional and attentional modulation of startle are variable and can occur at both early and late startle probe positions, depending on task requirements.
Memory for words and novel visual patterns: Repetition, recognition, and encoding effects in the event‐related brain potential
Authors: VAN PETTEN CYMA , SENKFOR AVA J.
Published: February 2007

Event‐related potentials (ERPs) were recorded during initial study and recognition of words and novel visual patterns. Words and patterns yielded similar recognition results that discriminated correctly recognized old items from correct new items, incorrect old items, and incorrect new items. The study phase data included a number of dissociations between words and patterns. Occasional repeated items yielded faster reaction times for both stimulus types but a late positive ERP repetition effect for words only. The study phase data differentiated words that would later be recognized versus unrecognized, but the patterns did not yield a similar encoding effect. Moreover, the study phase positivity contingent on subsequent recognition was restricted to words that received a positive semantic judgment during study. The functional relationships among the repetition, recognition, and encoding effects are discussed.
Influence of beliefs about heart rate and actual heart rate on heartbeat counting
Authors: RING CHRISTOPHER , BRENER JASPER
Published: February 2007

The heartbeat counting task is used widely to assess the ability to perceive cardiac sensations. However, performance on this task may be determined by processes other than sensitivity to cardiac stimuli. Beliefs about the effects of postural and exercise challenges on heart rate were assessed by questionnaire prior to performing the heartbeat counting task, and then actual heart rate was manipulated during the counting task by changes in posture and exercise. On average, counted heart rates were closer to beliefs about heart rate than to actual heart rate. Hierarchical multiple regression analyses indicated that (a) believed heart rates predicted counted heart rates while controlling for actual heart rates and (b) actual heart rates also predicted counted heart rate while controlling for heart rate beliefs. These data suggest that the rate of heartbeat counting is influenced by beliefs about heart rate and by the processing of cardiac sensations.
Does the heart know what the ears hear? A heart rate analysis of auditory selective attention
Authors: VAN DER MOLEN MAURITS W. , SOMSEN RIEK J. M. , JENNINGS J. RICHARD
Published: February 2007

Between‐ and within‐channel auditory selective attention were examined by presenting subjects with tone pips randomly to opposite ears; some pips had a slightly different pitch. Subjects were instructed to count rare, deviant tone pips at one ear and ignore all input to the other ear. Heart rate was sampled twice: once for the attended tone pips and once for the nonattended stimulus series. Heart rate responded differently to attended tone pips. While subjects were waiting for the rare stimulus to occur, heart rate slowed until the deviant stimulus was detected, which was followed by heart rate acceleration. Anticipatory heart rate deceleration was largely absent for nonatended series, and rare tone pips presented at the nonattended ear were not followed by acceleratory recovery. All tone pips elicited cardiac cycle time effects, that is, stimuli presented at short delays after the R wave prolonged the concurrent interbeat interval more than stimuli presented later. The cardiac cycle time effect was not altered by stimulus relevance (attended vs. nonattended) or significance (standard vs. rare). These results suggest that all stimuli receive preliminary perceptual analysis, but only attended stimuli are processed for further evaluation.
Principal component analysis of event‐related potentials: Misallocation of variance revisited
Authors: ACHIM ANDRÉA , MARCANTONI WALTER
Published: February 2007

Misallocating variance, in event‐related potential analysis, refers to attributing an experimental effect to components not actually affected. A vector interpretation of the relationship between mathematically derived and true underlying components shows that misallocation depends exclusively on incorrect identification of the affected component. Simulations, using seven imperfect rotations, confirmed all predictions from the vector interpretation concerning the presence, direction, and size of misallocated variance. Contrary to principal component analysis (PCA), Möucks's topographic component model (TCM) is not subject to rotation problems. These two methods were compared over 100 simulations in which the components had constant waveforms and topographies across participants. The group effect was always detected, but only PCA and not TCM showed significance on other components, except when their random weights happened to differ between groups.
Manipulating affective state using extended picture presentations
Authors: SUTTON STEVEN K. , DAVIDSON RICHARD J. , DONZELLA BONNY , IRW1N WILLIAM , DOTTL DARREN A.
Published: February 2007

Separate, extended series of positive, negative, and neutral pictures were presented to 24 (12 men, 12 women) undergraduates. Each series was presented on a different day, with full counterbalancing of presentation orders. Affective state was measured using (a) orbicularis oculi activity in response to acoustic startle probes during picture' presentation, (b) corrugator supercilii activity between and during picture presentation, and (c) changes in self‐reports of positive and negative affect. Participants exhibited larger eyeblink reflex magnitudes when viewing negative than when viewing positive pictures. Corrugator activity was also greater during the negative than during the positive picture set, during both picture presentation and the period between pictures. Self‐reports of negative affect increased in response to the negative picture set. and self‐reports of positive affect were greatest following the positive picture set. These findings suggest that extended picture presentation is an effective method of manipulating affective state and further highlight the utility of startle probe and facial electromyographic measures in providing on‐line readouts of affective state.
Cardiovascular responses during effortful active coping and acute experience of anger in women
Authors: BONGARD STEPHAN , PFEIFFER JUTTA S. , AL'ABSI MUSTAFA , HODAPP VOLKER , LINNENKEMPER GABI
Published: February 2007

This study addresses the question of whether effortful active coping and anger provocation add in their effects on cardiovascular responses. Heart rate (HR), systolic blood pressure (SBP), and diastolic blood pressure (DBP) responses of 64 female students were collected during an active versus nonactive coping task with and without provocation. After a baseline period, women did mental arithmetic (active coping) or read numbers aloud (nonactive coping). Half of each group was then additionally provoked. Ratings of the emotional states (Positive and Negative Affect Scale) indicate that provocation led to an increase in anger, but not in fear or negative or positive affect. Effortful active coping and provocation elevated cardiovascular activity. Although active coping enhanced all cardiovascular variables, provocation particularly affected HR and DBP. The effects of active coping and provocation on HR and DBP but not on SBP were additive and probably were produced by different physiological mechanisms.
On the detection of auditory deviations: A pre‐attentive activation model
Authors: SCHRÖGER ERICH
Published: February 2007

The conscious perception of infrequent deviant sounds occurring in a series of frequent standard sounds may in part be based on the output of an obligatorily operating deviance detection system. This system encodes invariances inherent to the recent auditory stimulation into short‐lived representations of auditory sensory memory and compares each actual input with these representations. The underlying processes may be regarded as preattentive in the sense that they do not rely on the explicit intention of a person to detect deviants and that they may be active even in the absence of attention (although they may be prone to attentional modulations). The output of this feature‐specific preattentive deviance detection system fuses into an integrated mismatch signal that in turn may activate subsequent processes that result in the triggering of a motor response.
Temporal characteristics of auditory sensory memory: Neuromagnetic evidence
Authors: MCEVOY LINDA , LEVÄNEN SARI , LOVELESS NORMAN
Published: February 2007

We investigated the temporal dependencies of N100m, the most prominent deflection of the auditory evoked response, using whole‐head neuromagnetic recordings. Stimuli were presented singly or in pairs (tones in the pair were separated by 210 ms) at interstimulus intervals (ISIs) of 0.6–8.1 s. N100m to single stimuli and to the first tone of the pair had similar temporal recovery functions, plateauing at ISIs of 6 s. N100m to the second tone in the pair, which was smaller than that to the first except with short ISIs, plateaued with ISIs of about 4 s. Source analysis revealed that the N100m could be decomposed into two sources separated by about 1 cm on the supratemporal plane. The recovery function of the posterior source was not affected by stimulus presentation, whereas that of the anterior source was. Activity in the anterior area appears to reflect the effects of temporal integration. We relate these results to auditory sensory memory.
The pupillary light reflex cannot be used to measure sleepiness
Authors: RANZIJN ROB , LACK LEON
Published: February 2007

The pupillary light reflex (PLR) has been considered by some researchers to be responsive to changes in levels of sleepiness. However, no previous studies have tested this hypothesis with the dramatic variation of sleepiness across a complete circadian cycle. In this experiment, 20 normal individuals (age: 18–48 years) underwent a 27‐hr constant routine, during which they were kept awake except for a 15‐min nap opportunity every hour. Sleepiness was assessed both subjectively, by the Stanford Sleepiness Scale, and objectively, by a modified version of the Multiple Sleep Latency Test. The PLR in response to a flash of light was recorded every 2 hr, immediately before a nap period. Results showed that baseline pupil diameter became smaller with progressive sleep restriction, but there were no changes in any of the parameters of the PLR despite significant fluctuations in sleepiness. Some of the changes in the PLR were significantly related to changes in baseline pupil diameter. When baseline diameter was partialled out, there was still no effect of sleepiness on the PLR. The results suggest that the PLR cannot be used as a measure of sleepiness.
P300 event‐related potential heritability in monozygotic and dizygotic twins
Authors: KATSANIS JOANNA , IACONO WILLIAM G. , MCGUE MATTHEW K. , CARLSON SCOTT R.
Published: February 2007

The present study examined the heritability of the P3 waveform and the N1, P2, and N2 components by assessing the visual event‐related potential (ERP) of 30 monozygotic (MZ) and 34 dizygotic (DZ) twin pairs. Electroencephalogram activity was recorded from Pz, P3, and P4 scalp sites while individuals performed a reaction time task involving two conditions differing in difficulty. Genetic modeling indicated substantial genetic influence on P3 amplitude, P3 latency, and manual reaction time for the difficult condition. No significant heritability was found for the latency of P3 or manual reaction time for the easy condition, but P3 amplitude was heritable for this condition. The amplitude of the early components (N1, P2, and N2) was heritable, but no significant genetic influences were found for the latency of these components. Compared with the DZ twins, the greater similarity of the MZ pairs on the event‐related potential measures was not due to their greater similarity in either head dimensions or mental ability, despite the facts that IQ scores were weakly correlated with P3 and N2 amplitude and that amplitude and latency were related to some measures of head size. These findings suggest that P3 amplitude and the amplitude of earlier ERP components are under partial genetic control, supporting the notion that these ERP components could perhaps be used to identify genetic risk for psychopathology.
Allocation of attentional resources during habituation to food cues
Authors: EPSTEIN LEONARD H. , PALUCH ROCCO , SMITH J. DAVID , SAYETTE MICHAEL
Published: February 2007

Two experiments were designed to test the hypothesis that habituation to repeated food cues can be inhibited by allocating processing resources to nonfood cues. In two experiments, the salivary response to 10 presentations of lemon yogurt was assessed while subjects engaged in a controlled cognitive search task (demanding attentional resources), an automatic search task (needing fewer attentional resources), or no task. In Experiment 1, the controlled and automatic search tasks differed in the number of memory set items. In Experiment 2, the size of the memory sets was held constant, and individuals were provided practice to stabilize the different search strategies in the task. The automatic search and no task groups habituated to the repeated presentation of food cues in both experiments, but the controlled search group did not. These results support the hypothesis that allocation of attentional resources to external cues can influence the processing of food cues.
Do tinted spectacle lens wearers have a different personality?
Authors: Eperjesi F.
Published: February 2007

The wearing of tinted spectacle lenses is considered by some health care workers to be a marker of psychopathology or a hypochondriacal personality type. The purpose of this study was to determine whether there is a relationship between the wearing of tinted spectacle lenses and personality type in physically healthy subjects. The Sixteen Personality Factor Questionnaire 5th Edition, a multidimensional standardized self‐report inventory, was used to determine the personality type of 98 participants. Twenty currently wore tinted spectacle lenses for reasons other than ocular disease, sun protection, outdoor or indoor glare reduction, pattern sensitive epilepsy, migraines, reading difficulties or fashion. The remainder did not wear tinted spectacle lenses for any purpose other than sun protection. Tinted lens wear and no tinted lens wear groups were age and gender matched. There was no statistically significant difference in five global personality factors between the no‐tint and tint groups: extraversion (p = 0.31), anxiety (p = 0.75), tough‐mindedness (p = 0.96), independence (p = 0.63), and self‐control (p = 0.87). This suggests that the use of tinted lenses by physically healthy people is unlikely to be an indicator of personality type.
Field evidence on nitrogen losses by denitrification
Authors: Batey T. , Killham K.
Published: February 2007

Abstract. Evidence based on observations of colour, growth and measurements of stem nitrate on carrots and sugar beet, colour and yield of grass, and of yield of wheat in different areas of Britain showed that growth and yield may have been substantially reduced in the wet summer of 1985 due to deficiency of nitrogen following large losses by denitrification. An account of die processes involved is given, together with observations and tests on affected soils. These were compared with field measurements of denitrification also made in 1985, under barley.

Examination of climatic data suggests that there were several periods in May, June, July and August when the soils close to the surface would have been saturated for days on end, and in the presence of many tine roots typical of crops at that time of year, the onset of an anaerobic state and accompanying denitrification would have been highly likely. The field evidence in 1985 suggests that nitrogen losses may have been much higher than those reported previously from research station investigations.
Problems of deducing the soil water balance in dryland regions from Meteosat data
Authors: Milford J.R.
Published: February 2007

Abstract. Meteosat is a geostationary satellite which observes the earth from the same point every half hour and views many of the drylands of Africa. Its data can be processed to provide information on the state of the surface of the earth, and its moisture condition in particular, by evaluating the thermal inertia from observations of the diurnal temperature cycle of the surface. This method is limited by the simple radiometry and low spatial resolution of Meteosat. The surface temperature amplitude cannot be known to better than 2°C, and the heat flow into the ground to 20%. As a result the actual values of thermal inertia can be known only to this accuracy.

Interpretation of thermal inertia is ambiguous, and alternative interpretations of any given value are discussed, showing little information on conditions more than 10 cm below the surface, and limited discrimination over soil moisture contents even in the topmost layer. Despite these difficulties, thermal inertia values could be calculated routinely. This could give information on the detailed distribution of rain from convective storms for agricultural monitoring and for large‐scale meteorological models.
Tillage and water conservation: experience in the Pacific Northwest
Authors: Papendick R.I.
Published: February 2007

Abstract. Tillage practices for water conservation in the Pacific Northwest, USA, wheat region emphasize the infiltration and retention of winter rain and snow and suppression of evaporation and transpiration by weeds. The wheat‐fallow system dominates in the semi‐arid areas and winter wheat‐spring crop rotations are most common in the sub‐humid areas. The main features of water conservation during the fallow season include chisel ploughing in the autumn to reduce winter runoff, and spring and summer tillage to kill weeds, minimize evaporation, and conserve seed‐zone water. Water in the seed zone is conserved by establishing a soil mulch having properties that thermally insulate the seed zone while at the same time restricting upward liquid and water vapour flow. Water conservation in the more humid zones involves chisel ploughing in autumn, uphill ploughing, and stubble retention to reduce winter runoff. New practices include minimum tillage and no‐till planting methods which maintain surface residues. However, heavy equipment associated with current trends in no‐till is causing soil compaction which may decrease infiltration rates. Methods under experimentation to improve infiltration with conservation tillage systems include slot mulching, paraplowing, and the use of basin pitters.
Hard‐setting soils
Authors: Mullins C.E. , Young I.M. , Bengough A.G. , Ley G.J.
Published: February 2007

Abstract. Hard‐setting soils are widespread in dry regions. Their properties are described and a physical explanation for hard‐setting behaviour is given. The limitations on soil management and physical fertility caused by hard‐setting depend on timing of rainfall or irrigation with respect to cultivations and crop development, and much research is needed to quantify reductions in crop yield imposed by these limitations.
Field drainage, soil water management and flood hazard
Authors: Parkinson Robert , Reid Ian
Published: February 2007

Abstract. The efficient management of clay soils depends on the rapid disposal of water following rainfall. Winter storm outfall hydrographs of under drained catchments ranging in size from 0.44 ha to 7.2 km2 are given, illustrating the drainage response of a Windsor Series soil. The response time of different sized catchments is discussed in relation to potential flood hazard arising from drainage improvements of agricultural land. Comparison is made with other soils to reveal broadly similar patterns of drainflow, with peak flow occurring typically between 1 and 4 hours after the mid‐point of a storm. Despite large fluxes of water through the soil profile, the water content of the soil within the catchment of an individual tile lateral is shown to vary only by small amounts both during and after a single rainstorm and over a drainage season.
Some physical features of soil after opencast mining
Authors: King J. A.
Published: February 2007

Abstract. The soil of a restored opencast site in Northumberland is described and compared with the surrounding undisturbed soil. The most serious change in the soil was increased bulk density at the surface of the subsoil (0.3 m depth). Only a small overall reduction in pore space occurred, at the expense of continuous macropores. More of the pore space in the restored soil occurred as fine fissures as opposed to biotic channels, and the restored soil was weaker because of subsoiling and a loss of stability in microstructures. These changes are discussed in relation to root exploration, water movement and land management.
The influence of soil properties on the environmental mobility of caesium in Cumbria
Authors: Livens F.R. , Loveland P.J.
Published: February 2007

Abstract. The interaction of caesium isotopes with soil has been widely investigated and the influence of important soil properties studied. From the results of such work and a detailed knowledge of the physico‐chemical properties of soils it is possible to classify Cumbrian soil according to its ability to immobilize caesium. The ‘immobilization capacity’ is a reflection principally of the clay mineral content and type, organic content, pH, ammonium content and potassium status. Although it is not quantifiable, the immobilization capacity permits ranking of the soils and indicates which areas may give rise to persistent caesium problems. Combination of the soil sensitivity classification with deposition data for Cumbria indicates that the mountainous region in the south‐west of the county is the most vulnerable. This conclusion is supported by field evidence, since the area identified coincides closely with that where sheep movement and slaughter are restricted and where caesium remains persistently available to the plant‐animal chain.
The leaching of salts from saline heavy clay soils: factors affecting the leaching process
Authors: Tanton T.W. , Rycroft D.W. , Wilkinson F.M.
Published: February 2007

Abstract. Cracks in dry saline montmorillonitic clay allow the soil to wet rapidly when flooded with negligible redistribution of salts. Once closed the only effective pathways remaining for the movement of leaching water are old root channels and faunal burrows. However, their effectiveness in conducting water and for leaching is severely restricted because of the lack of horizontal connections between them. Restructuring of clay can introduce sufficient permeability to a depth of about 0.7 to 0.8 m to allow salt to be leached provided that the soil's initial moisture content is sufficiently large to prevent disintegration upon wetting (about 24%) and that the clay is not allowed to become unsaturated during the leaching.
Techniques of crop yield assessment for agricultural land evaluation
Authors: Dumanski J. , Onofrei C.
Published: February 2007

Abstract. Land evaluation involves the definition of the comparative marginal value of individual land areas for the uses being considered. For agricultural land evaluation crop yields are the most reliable estimates of comparative marginal values. Yield values can be obtained from field measurements, as well as from productivity indices and empirical and mechanistic crop growth models. This paper reviews the pros and cons of each approach. Mechanistic models of the summary type, that simulate only those processes that are critical to describe an agroecosystem, are the most realistic and practical tools for land evaluation. Criteria for these types of models are given.
Nitrogen accumulation, cycling and the restoration of ecosystems on derelict land
Authors: Marrs R.H.
Published: February 2007

Abstract. Nitrogen deficiency is the major problem in the creation of new ecosystems on most derelict land. Initially there is insufficient nitrogen in the wastes to drive the new systems, and nitrogen accumulation is, therefore, required. The most cost‐effective way of providing this nitrogen is to use leguminous species which fix nitrogen from the atmosphere. Once nitrogen starts to accumulate in the soil management should aim to promote efficient cycling. Maintaining a near‐neutral soil pH and a sward with a small C:N ratio helps to increase the mineralization of nitrogen in dead plant residues, and grazing animals also reduce nitrogen accumulation in dead vegetation.
Nitrogen deposition to land from the atmosphere
Authors: Goulding K.W.T.
Published: February 2007

Abstract. One direct measurement and two indirect estimates suggest that 35–40 kg nitrogen per hectare are deposited on arable land from the atmosphere each year in the south and east of England. This could contribute markedly to nitrate leaching and soil acidification. It may also change the flora and fauna of ‘natural’ ecosystems, as such amounts are likely to exceed the critical load.
Mapping potentially marginal land in Denmark
Authors: Breuning‐Madsen H. , Reenberg A. , Holst K.
Published: February 2007

Abstract. Wet and droughty soils and those on steep slopes are now marginal for agriculture in Denmark. A nation‐wide map of these soil types has therefore been made to show their distributions. This was based on an existing soil database containing maps and analytical data. The paper describes the methods used to extract and display the data.
The influence of land management on concentrations of dissolved organic carbon and its effects on the mobilization of aluminium and iron in podzol soils in Mid‐Wales
Authors: Hughes S. , Reynolds B. , Roberts J.D.
Published: February 2007

Abstract. The aluminium (Al), iron (Fe) and Dissolved Organic Carbon (DOC) contents of the soil solution were monitored in two upland grassland and afforested podzol soils in Mid‐Wales. Al organo‐metallic complexes predominated in the O horizon leachates of the grassland soil, whereas inorganic monomeric Al forms dominated in the lower mineral horizons. Dissolved organic matter determines the chemistry, solubility, and transport of Al and Fe in the O horizon, and these are under strong biological control. The distributions of organic‐Al, Fe and DOC within the soil profile were consistent with traditional podzolization theory. Observed increases in the molar ratios of Al:DOC in solution in the lower soil horizons may be responsible for the small solubility of Al organo‐metallic complexes in those horizons. Afforestation increased the concentrations of organic‐Al and Fe in the soil solution as compared with the concentrations observed for the grassland soil. Clearcutting further significantly mobilized Al and Fe from the upper soil horizon, primarily by increasing the DOC concentration in the soil water.
A rapid, inexpensive and quantitative procedure for assessing soil structure with respect to cropping
Authors: Koppi A.J. , Douglas J.T.
Published: February 2007

Abstract. The essential factors dependent on soil structure that influence plant growth are soil/root contact, adequate air and water, and low mechanical impedance. Bulk density, shear strength and texture arc interrelated closely and permit quantification of these factors. A general relationship between clay content and vane shear strength of soil at field capacity and non‐limiting bulk density provides a rapid means of quantitatively estimating structure. We propose a procedure utilizing vane shear strength and a tactile assessment of clay content as criteria for judging soil structure in the field.
The variability of winter drainage in England and Wales
Authors: Rose D.A.
Published: February 2007

Abstract. Estimates of winter drainage, D, are available for 82 locations in England and Wales for each winter during the 35‐year period, 1940/1 to 1974/5. At each location, D is approximately normally distributed. The variability, expressed as a coefficient of variation, is approximately inversely proportional to the average drainage; it is large, ranging from 20–30% in Wales and the uplands of northern and western England to 60–70% in eastern England. Assuming a normal distribution, the probability of exceeding a given amount of drainage is easily found.

The proportion, f of solute initially in the soil that is leached each winter can be calculated using these estimates of D in a simple layer model. However, f is not normally distributed, but can be fitted by the Type‐1 extreme‐value distribution.

If there are n years of data, and m is the rank of a value in order of decreasing size, the estimation of the probability, P, of exceeding the mth largest value, fm, is P(ffm) =m/(n+1), and the return period, t, is 1/P years. Using the transform, W= In[—In P], graphs of/against W yield families of lines that, for a given location and depth in the soil, depend only on soil type, and from which extreme values likely to be encountered in a given return period can be forecast. Results are discussed for Mildenhall, Suffolk (= 99 ± 68 mm), Cockle Park, Northumberland (±= 275 ± 125 mm), Welshpool, Powis (±= 373 ± 121 mm), Carmarthen, Dyfed (±= 764 ± 196 mm) and Ambleside, Cumbria (±= 1280 ± 276 mm).
Soil monitoring: a basic task for soil survey organizations
Authors: Young A.
Published: February 2007

Abstract. A basic task of national soil survey organizations should be to monitor changes in soil properties. The objectives would be to establish which land‐use systems, on which soil types, are causing decline in fertility, and to keep track of the effects of pollution. Unless data are obtained at national level, attempts to monitor global soil changes cannot succeed.
The depth and productivity of chalky soils
Authors: Burnham C. P. , Mutter G. M.
Published: February 2007

Abstract. In south‐east England, no relation between cereal yield and soil depth is shown by field estimates or harvesting microplots with depths to compact chalk of 23–121 cm. Differences in yield of ryegrass and wheat grown in cylinders containing artificial profiles with different thicknesses of topsoil, subsoil, chalk rubble and clean chalk from the Panholes series on Middle Chalk were attributed almost entirely to different amounts of nutrients. Chalk fragments supplied about 20% by weight of moisture to plants, and topsoil and subsoil about twice as much. Laboratory studies confirmed that fragments of Middle Chalk from near Wye (Kent, UK) hold about 20% water under tensions between 30 and 1500 kPa, but showed that topsoil and subsoil hold slightly less than this. The discrepancy in estimating water holding capacity arises because profiles over compact chalk drain only slowly from saturation. In this wet state they are very vulnerable to water erosion. It was also observed that ryegrass roots under water stress can penetrate well rammed chalk rubble, and that substantial amounts of water can rise 20 cm through solid chalk within a few days. It is concluded that soil losses resulting from erosion over normal porous chalks diminish cereal yields only slightly provided nutrient levels are maintained.
Decreasing the impact of surface crusting on seedling: emergence by spray wetting
Authors: Shiel R. S. , Yuniwo E. C.
Published: February 2007

Abstract. . A soil crust, produced by applying 44 mm of distilled water at an intensity of 290 mm/h using a rainfall simulator, was sufficiently rigid to significantly decrease emergence of barley from 76 to 40% and of oil seed rape from 82 to 61%. If the crust was kept wet by regular application of water as a fine mist, its strength was significantly decreased, but emergence remained poor because of prolonged soil wetness. After mist‐spraying the crusted surface just before emergence, per cent emergence was greater than uncrusted controls.

Application to the soil of a static pressure after sowing but without crusting either had no effect or increased emergence, probably because of improved seed‐soil contact. However, crusting of the compacted soil decreased emergence severely. If the crust was allowed to dry it became very strong (> 300 kPa). Mist‐spraying at the time of emergence only also improved seed emergence almost to that in the uncrusted controls. Repeated mist spraying after crusting decreased the strength of the crust, but the resulting waterlogging decreased emergence to less than half those of the controls and of the treatments sprayed just before emergence only. Compared with other management techniques available for amelioration of crusted seedbeds, carefully timed fine spray watering seems to offer the best opportunity for ensuring rapid seed emergence comparable to that in uncrusted soils.
Quantified evaluation of agricultural soil capability at the local scale: a GIS‐assisted case study from Ontario, Canada
Authors: McBride R. A. , Bober M. L.
Published: February 2007

Abstract. Rural agricultural areas in southern Ontario, Canada, with potential for aggregate extraction have become a focus of conflict over proposed land use change. Geophysical and soil physical field measurements were used to map soil variation for quantitative land evaluation at the farm level. Apparent electrical conductivity of terrain was shown to be strongly correlated with depth to the groundwater table on two separate test sites. A digital terrain model was used to create thematic maps of the predicted pre‐growing season soil water regime by contouring irregularly spaced electromagnetic survey and soil inspection points. Overlay analysis with a geographical information system (GIS) was used to produce an agricultural soil capability map for crop production. Adoption of a larger map scale provided significant refinement in detail over the published Canada Land Inventory soil capability ratings for agriculture, but both showed that Class 2 soils are dominant. The approach can improve the reproducibility of land capability assessments.
The use of soil in colliery spoil reclamation
Authors: Gildon A. , Rimmer D. L.
Published: February 2007

Abstract. Field trials measured the benefits of using soil in the reclamation of colliery spoil. Increasing the thickness of the soil cover increased grass yield, particularly on a site with potentially acidic spoil materials. Mixing soil with the underlying spoil increased yield slightly compared to using the same amount of soil as a cover. From these and earlier results, we conclude that: the use of soil as a cover is essential on sites with acidic, or potentially acidic, spoil; to be effective in the short‐term, the thickness of soil can be as little as 15 cm; the use of soil on sites with non‐acidic spoil is beneficial in terms of physical conditions, such as improved water‐holding capacity and better root penetration; the benefits of incorporating the soil on such sites are probably insufficient to justify the additional effort involved.
Maize growth responses to deep tillage, straw mulching and farmyard manure in coarse textured soils of N.W. India
Authors: Gajri P.R. , Arora V.K. , Chaudhary M.R.
Published: February 2007

Abstract. The effects of deep tillage, straw mulching and farmyard manure on maize growth in loamy sand and sandy loam soils were studied in experiments lasting three years. Treatments included all combinations of conventional tillage (10 cm deep) and deep tillage (35–40 cm deep), two farmyard manure rates (0 and 15 t/ha) and two mulch rates (0 and 6 t/ha), replicated three times in a randomixed block design.

Deep tillage decreased soil strength and caused deeper and denser rooting. Mulching decreased maximum soil temperature and kept the surface layers wetter resulting in better root growth. Farmyard manure also improved root growth, and the crop then extracted soil water more efficiently. All three treatments increased grain yield in the loamy sand, but in the sandy loam only tillage and farmyard manure increased yields significantly. Deep tillage and straw mulch effects varied with soil type and amount of rainfall in the growing season. In the loamy sand the mean responses to deep tillage and mulching were largest in a dry year. A tillage‐mulch interaction was significant in the loamy sand.
Nematodes as indicators of enhanced microbiological activity in a Scottish organic farming system
Authors: Griffiths B.S. , Ritz K. , Wheatley R.E.
Published: February 2007

Abstract.The presence of spring barley plants increased the numbers of nematodes, particularly of plant‐feeders, compared with fallow plots in a Scottish organic farming system. The addition of farmyard manure (FYM) had no detectable effect on nematode populations but poultry manure (PM) caused a considerable increase. The application of PM also altered the types of nematode present and favoured bacterial‐feeders and rhabditids in particular. These changes suggest that PM causes shortterm (within a growing season) increases in microbiological activity and nutrient cycling, whereas FYM is more likely to bring about long‐term changes.
Amelioration and management of soils irrigated with sodic water in the arid region of India
Authors: Joshi D.C. , Dhir R.P.
Published: February 2007

Abstract. Field studies at five locations on farmer's fields irrigated with residual sodium carbonate water (RSC) indicated that gypsum applications at the rate of 100% of the gypsum requirement of soil plus the quantity of gypsum required to neutralize RSC in excess of 4 mEq/1 decreased SAR values, and improved infiltration rate, crop emergence and wheat grain yields. The soil pH decreased by 0.3–0.4 units. Once soils have been ameliorated by this treatment, further small applications of gypsum are needed to decrease the RSC in irrigation water and avoid further soil deterioration.
Carbon storage and other properties of soils under agriculture and natural vegetation in São Paulo State, Brazil
Authors: Lepsch I.F. , Menk J.R.F. , Oliveira J.B.
Published: February 2007

Abstract. Topsoil (0–20 cm) and subsoil (60–100 cm) properties are compared at agricultural and nearby natural vegetation sites in São Paulo State. Differences are related to land use and climate, in order to estimate soil carbon storage under various ecosystems and also to study the effects of high‐input agriculture on the chemical composition of soils with low activity clays. Within each land use, organic carbon in the topsoil is most strongly related to clay + silt content. This relationship is stronger for cropped, short savannah (cerrado) and tall savannah (cerradão) sites than for semi‐deciduous and evergreen forest sites. Losses of topsoil carbon with cropping can be predicted if the initial carbon and the clay+silt contents are known. The greatest carbon losses after long term cultivation occurred in forest mineral topsoils, ranging from 6% for perudic clayey soils to 37% for ustic sandy soils. No significant difference in carbon content was found between the paired savannah‐cultivated sites. In most of the originally less fertile soils cation exchange capacity was greater in the cultivated topsoil (Ap) than in the topsoil under savannah or forest (A1), probably because of liming and phosphate fertilization. Most subsoils at agricultural sites show increases in exchangeable bases (mainly Ca) and base saturation, but no significant change in pH.
The determination of field‐saturated hydraulic conductivity in some Scottish soils using the Guelph permeameter
Authors: Lilly A.
Published: February 2007

Abstract. Soil hydraulic conductivities are frequently required for process‐based modelling of the soil water regime. Field‐saturated hydraulic conductivity was measured with the Guelph permeameter in 10 soil series with a range of structures and textures. The permeameter offers a range of options for calculating conductivities depending on soil conditions, particularly homogeneity of pore distribution within each horizon. However, even horizons described as massive or apedal were not sufficiently homogeneous to satisfy the boundary conditions entirely.

Hydraulic conductivities were calculated by the one head, fixed α* procedure; α* is an index of capillarity. No direct correlations were found between hydraulic conductivity and land use. However, the average hydraulic conductivity of coarse textured topsoils which were mainly under arable agriculture was less than that of the finer textured topsoils largely under grassland. Even limited structural development increased the hydraulic conductivities of fine textured, compact subsurface horizons. It is important to match the adopted procedure to the soil conditions both during the determination of flow rates in the field and in the subsequent analyses.
The soil condition of adjacent bio‐dynamic and conventionally managed dairy pastures in Victoria, Australia
Authors: Lytton‐Hitchins J.A. , Koppi A.J. , McBratney A.B.
Published: February 2007

Abstract. Physical and chemical properties were compared during 1992 in adjacent bio‐dynamic and conventionally managed Haploxeralfs under improved, summer‐irrigated pastures in the Goulburn Valley of N.E. Victoria. Intensive dairy production has been practised on both the farms since the early 1950s, and aspects of the bio‐dynamic method have been practised on one farm for the past 18 years. Particle‐size analysis showed that the soil profiles of each field are derived from similar parent materials. The bio‐dynamic soil had greater macro‐porosity to a depth of at least 420 mm, lesser soil strength at 60, 120 and 200 mm, smaller dry bulk density values between 120 and 200 mm and larger organic matter content in the upper 50 mm. Volumetric soil water content measured along three transects to a depth of 1.4 m in the summer showed that the bio‐dynamic field was drier at depths greater than 200 mm. After heavy rains during the winter, the conventionally managed soil had an air‐filled porosity unfavourable for plant roots (2%) at 200 mm depth, whereas the bio‐dynamic soil was marginal for root growth (7%). The more favourable physical and chemical properties in the bio‐dynamic soil may be attributed to less grazing pressure, longer intervals between irrigations, use of the bio‐dynamic horn‐manure preparation, intermittent compost applications, less tractor traffic and the encouragement of taller pasture growth.
Simulation of nitrogen dynamics in farmland areas of Denmark (1989–1993)
Authors: Jensen C. , Stougaard B. , Østergaard H.S.
Published: February 2007

Abstract. Each year since 1986 information has been collected about the farming systems at intersections of a nationwide 7 km square grid in Denmark. These management data and corresponding soil analyses were used in the model DAISY to simulate water and nitrogen dynamics. The model was validated with respect to harvested dry matter yield and nitrogen content in the soil. Simulated nitrate leaching from farmland areas from 1 April 1989 to 31 March 1993 was related to precipitation zones, soil type, fertilizer strategies and cropping systems. The mean simulated nitrate leaching for the whole of Denmark was 74 kg N/ha/yr, with a large yearly variation in the period considered. The simulated nitrate leached from soils with a sandy subsoil corresponded to 51% of the applied fertilizer, twice that leached from soils with a loamy subsoil. The application of pig manure resulted in average leaching losses of 105 kg N/ha/yr. The simulated nitrate leaching losses at sites where only artificial fertilizer was applied were in the following order: cereal with undersown grass < crop followed by winter cereal or winter rape < cereal or rape without a catch crop < root crops without a catch crop. Where only artificial fertilizers were applied, the simulated mean annual leaching was 59 kg N/ha from spring barley and 40 kg N/ha from winter wheat. A map of simulated nitrate leaching in Denmark was produced using a Geographical Information System.