bluuebunny/crossref_metadata_2025 huggingface dataset:
Application of the threshold concentration concept to irrigation with saline water
Authors: Rengasamy P. , Mehanni A.H.
Published: February 2007

Abstract. The applicability of the ‘threshold concentration’ concept in formulating guidelines for irrigating with saline water was tested under field conditions on red‐brown earths from different field experiments in south eastern Australia. Infiltration of water in the field and the effect of rainfall impact were studied using ring infiltrometers and a rotating‐disc rainfall simulator.

Three threshold concentration lines relating sodium adsorption ratio (SAR) and total cation concentration (TCC) in soil extracts were tested. These lines were based on laboratory tests of soil permeability, spontaneous dispersion and mechanical dispersion. They were found to predict the infiltration problems due to rainfall impact under three different surface soil conditions ‐ bare soil without cultivation, soil with no tillage and complete crop cover, and cultivated soils without any crop cover.

Infiltration rates in continuous pasture plots were predicted by the threshold concentration line of spontaneous dispersion except in a high salt treated soil where reduced plant growth affected evapotranspiration and water intake during infiltration.
Application of nested analysis of variance in mapping procedures for land evaluation
Authors: Riezebos Hans Th.
Published: February 2007

Abstract. Assuming that other sources of error can be neglected, the reliability of a land suitability classification depends on the homogeneity of physiographically delineated map units with regard to land qualities. The map unit homogeneity of a small area in France was estimated using 64 observation points, arranged according to a nested sampling scheme, followed by nested analysis of variance.

The analysis shows that in this area map units are too heterogeneous to accept the suitability classification as being completely reliable. However, alternative procedures using methods of optimal interpolation to map gradual change within the physiographic units are too expensive at a mapping scale of 1:25000 or smaller. It is not possible to produce completely accurate suitability maps at smaller scales. However, incorporating nested sampling and analysis of variance as standard procedures in land evaluation surveys costs little effort and yields at least an estimate of map accuracy and reliability of the suitability classification.
Integrated resource monitoring by means of remote sensing, GIS and spatial modelling in Arid Environments
Authors: Olsson Lennart
Published: February 2007

Abstract. The ultimate goal of resource monitoring is to analyse the spatial distribution of the balance between supply and demand of a certain resource. Remote sensing techniques are commonly used for the assessment of the supply of resources. By integrating remote sensing with the related techniques of geographical information systems and spatial modelling, the demand as well as the accessibility of resources can be analysed. The article gives an overview over methods for integrated resource monitoring. Examples from arid environments are also presented.
The influence of land capability on rural land sales: a case study in Renfrewshire, Scotland
Authors: Davidson Donald A.
Published: February 2007

Abstract. Since 1981 information on land sales has been recorded in the Land Register for some counties in Scotland. Rural land sale data for areas of more than 10 hectares in Renfrewshire have been analysed to determine the extent to which land capability, elevation and slope have an influence on land value. Although many factors influence the price paid for rural land, the effect of land capability in particular is demonstrated, with altitude having a minor effect. Using a best fit curvilinear model price ranges are predicted on the basis of land capability classes.
Principles of managing man‐made soils
Authors: Stewart V.I. , Scullion J.
Published: February 2007

Abstract. Assuming that there is no major chemical toxicity or deficiency, the major limitation in man‐made soil is the loss of its natural structure, which, in turn, controls the air‐water balance. Where such a soil has < 70% sand content this loss may adversely affect potential for use.

Examples of man‐made soils ‐ sports turf and replaced opencast coal mining land ‐ are used to illustrate principles of management. Two strategies exist: to encourage earthworms, thereby promoting effective site drainage by infiltration or, to limit their activity and rely mainly on surface shed. The implications of each of these soil options for wider management and use are discussed.
The restoration of mineral workings in Britain ‐ a review
Authors: McRae S.G.
Published: February 2007

Abstract. Techniques for restoring mineral workings to agriculture, forestry or amenity uses are described. An integrated scheme of working and restoration is vital, taking account of the soil resources available, appropriate methods of soil handling (usually by earthscraper or dump‐truck and excavator) and a programme of aftercare including underdrainage. Changes in soil during storage are discussed. Some of the potential problems where the site is infilled with imported wastes are reviewed. The success of restoration can be judged by comparisons of soil properties, crop performance or the general acceptability of the restored site to the local residents.
An editor's farewell
Authors: Webster R.
Published: February 2007

Abstract. The standard of English in papers submitted to Soil Use and Management varies from excellent to disgraceful. Good scientific English is direct and simple in structure. It uses familiar words in their correct sense and order with the minimum of qualification. Slovenly prose may imply slipshod research, and prolixity an inability to think clearly.

Make your meaning plain. Express it

So we'll know, not merely guess it.

(G.V. Jacks, The Summary)
ALES: a framework for land evaluation using a microcomputer
Authors: Rossiter David G.
Published: February 2007

Abstract. ALES, the Automated Land Evaluation System, is a microcomputer program that allows land evaluators to build their own knowledge‐based systems with which they can compute the physical and economic suitability of land map units, in accordance with the FAO's Framework for Land Evaluation. The economic suitability of a land mapping unit for a land utilization type is determined from the predicted annual gross margin per unit area. Increasing limitations result in increased costs of production, decreased yields, or both. Evaluators build decision trees to express inferences from land characteristics to land qualities, from land qualities to predicted yields, and from land qualities to overall physical suitability. A representative model is described.
Control of erosion in a mature orchard
Authors: Hipps N.A. , Hazelden J. , Fairall G.B.N.
Published: February 2007

Abstract. During 1986 erosion on soil mulched with 6 t ha‐1 of straw was compared with that on soil maintained bare by herbicides in a mature apple orchard. The orchard was on well‐drained soil with a sandy loam top on a slope of 2°. Erosion was greatest in the alleys between the trees, where traffic had compacted and smoothed the soil. The mean annual soil loss on bare ground in the alleys was 0.45 t ha‐1; straw mulch reduced this by 85%. Erosion was worst between July and October, when rainfall > 10 mm h‐1 was most frequent. However, differences in soil moisture and resistance to infiltration may have also contributed to differences in erosion throughout the year.
An introduction to the global nitrogen cycle
Authors: Jenkinson D.S.
Published: February 2007

Abstract. Current estimates are tabulated for the quantities of nitrogen circulating in the global nitrogen cycle. Five gases, NH3, N2O, NO, NO2 and N2, dominate the movement of nitrogen between the earth's surface and the atmosphere. The input of combined nitrogen to the land surface of the earth is tentatively estimated at 290 million tonnes per year, a total which includes 74 million tonnes from fertilizers. Known outputs from land (as gaseous NH3, N2O and NOX, and as inorganic nitrogen carried to the sea by rivers) are much less, totalling 130 million tonnes per year. Emissions of N2 gas probably account for most of the difference. There has been an increase in the use of nitrogen of about 5% per year over the last ten years. The demand for fertilizer nitrogen is likely to continue to grow if the population of the world continues to increase.
The biology of nitrogen transformations
Authors: Sprent J.I.
Published: February 2007

Abstract. A brief resumé of the organisms involved in the nitrogen cycle is given. Benefits accruing to micro‐organisms are considered in two categories: (1) where the reaction product is incorporated into cells (nitrogen‐fixing and nitrate assimilating species), (2) where the reaction is used to provide energy for growth (nitrifying and denitrifying species). Some aspects of nitrogen cycling in soils are briefly considered, including inhibition of nitrification, the importance of C/N ratios and nitrate pollution.
Use of NMR spectroscopy to study transformations of nitrogenous substances during incubation of peat
Authors: Cheshire M.V. , Williams B.L. , Benzing‐Purdie L.M. , Ratcliffe C.I. , Ripmeester J.A.
Published: February 2007

Abstract. Samples of peat were incubated with 15N‐labelled ammonium sulphate, urea, wheat straw and glycine and divided into six size fractions of solid components and a water‐soluble fraction. The fractions were analysed by NMR spectroscopy to study the formation of humic substances and rind how fertilizer nitrogen is immobilized in peaty soils. After six months' incubation about half of the ammonium sulphate nitrogen was still present as ammonium in the soluble fraction, the urea had been entirely metabolized to ammonium and various organic compounds, about half the straw had been decomposed to ammonium and amino acid or peptide materials, and most of the glycine had been transformed to ammonium, amide and aliphatic amine.
Fertilizers and soil‐borne diseases
Authors: Huber D.M.
Published: February 2007

Abstract. Nutrient manipulation through fertilization or modification of the soil environment to influence nutrient availability is an important cultural control for plant disease and an integral component of production agriculture. Fertilization decreases soil‐borne diseases by maximizing the inherent disease resistance of plants, by facilitating disease escape through increased nutrient availability or stimulated plant growth, and by altering the external environment to influence the survival, germination and penetration of pathogens. The flexibility in most disease‐nutrient interactions permits a much broader utilization of this cultural control in decreasing disease severity than is presently practised. It is clear that the severity of most diseases can be decreased and the chemical, biological or genetic control of many plant pathogens enhanced by proper fertilization. Breeding nutrient‐efficient or disease‐tolerant crops and establishing cultivar requirements should further improve production efficiency.
Current status of biological control of soil‐borne diseases
Authors: Campbell R.
Published: February 2007

Abstract. Biological control by manipulating agricultural practices has been used for thousands of years. In the more restricted sense, of adding antagonistic micro‐organisms, biological control is still a very small part of the chemical pesticide market, but reliable products are becoming available. Achieving consistent results in realistic agricultural conditions is a problem, but there is a good possibility of controlling root diseases, especially where the soil characteristics or the environmental conditions can be controlled. The use of biological control in integrated control is successful, and in the long‐term genetic engineering techniques will be important in the development of biological control. Environmental safety and effective patent protection are still being developed, but there seem to be no insuperable problems.
The impact of soil and crop management practices on soil‐borne root diseases and wheat yields
Authors: Rovira A.D.
Published: February 2007

Abstract. The most important root diseases of wheat in southern Australia are take‐all, rhizoctonia bare patch and cereal cyst nematode. Control of grasses in annual pastures in the year preceding wheat crops decreased take‐all on wheat and the amount of the take‐all fungus in soil, decreased the damage caused by Rhizoctonia, and gave yield increases. Fumigation of cereal‐growing soils gave yield increases in wheat of 0.75 to 2.8 tonnes per hectare, indicating that in southern Australia soil‐borne root diseases impose a major constraint on productivity. Residues of the herbicide chlorsulfuron one year after application to an alkaline soil increased root damage by Rhizoctonia in barley and decreased grain yields by 1.5 tonnes per hectare. Root damage by cereal cyst nematode was decreased by direct drilling wheat and also by having a barley cultivar resistant to the pathogen as a preceding crop. The number of cysts of cereal cyst nematode on wheat roots was increased by the application of superphosphate in bands with the seed. These results show that in southern Australia soil management strategies which decrease the levels of root disease greatly increase grain yields.
Artificial infestation of soil with Gaeumannomyces graminis var. tritici to study the relationship between take‐all and wheat yields in field experiments
Authors: Hornby D. , Bateman G.L.
Published: February 2007

Abstract. The relationship between take‐all and grain yield was investigated in a first spring wheat crop grown in a field experiment on artificially infested soil. Different incidences and severities of disease were obtained by using different cultivations to incorporate equal amounts of inoculum (killed oat grains colonized by the fungal pathogen) at different depths. The intention of incorporating inoculum at different stages in the same sequence of cultivations to achieve identical soil conditions with inoculum at different depths was not entirely successful because of weather conditions.

For most sampling dates and different assessments of disease, there was a strong relationship between yield and disease: regression coefficients were negative and significant (P= 0.01). The linear regression model using logit transformations of disease data from infestations achieved using similar sequences of cultivations accounted for > 70% of the variance at all sampling dates, but with untransformed data (percentage plants and percentage roots infected) percentages of variance accounted for were much less at sampling times before anthesis. The plot area affected by premature ripening (whiteheads) also correlated well with yield where similar sequences of cultivations were used, but less well where rotovating to different depths created different soil conditions.

The results are discussed in relation to published results from (1) farm surveys, (2) field experiments with natural infection and (3) experiments using different amounts of artificially‐produced inoculum. The wider application of artificially‐produced inoculum in field experiments on take‐all is also considered.
Measurement of nitrate leaching losses from arable plots under different nitrogen input regimes
Authors: Vinten A.J.A. , Howard R.S. , Redman M.H.
Published: February 2007

Abstract. Leaching losses of nitrate‐nitrogen were measured from a set of eight hydrologically isolated plots on a clay loam soil over the period from September 1987 to February 1990. Variable drainflow recovery from the plots hampered accurate estimation of nitrate loading, but results suggest that, when inorganic nitrogen fertilizer is applied up to the recommended amount, there is little influence of the amount applied on the amount leached. We did, however, observe the following effects on nitrate leaching: leguminous green manure incorporated in autumn increased leaching of nitrate‐nitrogen by 10–15 kg per hectare during the winter; autumn cultivation caused some increase in leaching compared with no cultivation in one year; some systematic variations in nitrate leaching occurred between years and between plots, but were unrelated to treatments.

From the results we conclude that green manuring does not provide sufficient nitrogen for organically grown crops on this soil but contributes significantly to nitrate leaching, and that growing spring cereals, with the land remaining in stubble as long as possible in autumn, may be the best strategy to minimize nitrate leaching.
The Zambian Land Evaluation System (ZLES)
Authors: Chinene V.R.N.
Published: February 2007

Abstract. A Land Evaluation System for rainfed agriculture has been developed in Zambia. It is intended for use in reconnaissance and semi‐detailed land evaluation studies, and works with 74 subqualities, 40 crops and four input levels. The subqualities are rated and converted into constraint classes per input level. The most limiting constraints determine the final suitability class. Expected yields per suitability class and input level are then estimated. The system was calibrated by a field study at four locations. Comparisons were made between expected and actual yields and expected and actual constraints. The range of actual yields was wider than that expected, probably because of variation in management between farmers. The average actual and expected yields were strongly correlated, but chi‐squared tests showed that they were significantly different. The system generally works well in assessing land suitability for crops commonly grown in Zambia.
Soil mixing in the East Anglian fens
Authors: Richardson S.J. , Dyer C.J. , Jewell S.N.
Published: February 2007

Abstract. Experiments were started in 1967 to investigate the effects of soil mixing on fen peat soil. Peaty topsoil was mixed with mineral subsoil to a maximum depth of 80 cm at two sites, one with a clay subsoil, the other sand. Mixing was done on a commercial scale with a range of implements. After initial increases, yields of arable crops on both mixed soils were subsequently similar to those on unmixed soil. Residual herbicide activity was enhanced on mixed soils, and evidence of peat conservation was obtained at one site. The practice has not been taken up commercially because of the high capital cost of mixing and lack of serious problems which had been predicted following peat wastage.
Relationships of saturation and B horizon colour patterns in soils of three hydrosequences in south‐central Michigan, USA
Authors: Mokma D.L. , Cremeens D.L.
Published: February 2007

Abstract. Relationships between soil colour patterns and depth and duration of water tables were studied using piezometers in three soil hydrosequences. A colour index was developed to quantify matrix colour, size and colour of mottles, and continuity and colour of clay films. It correlated well with duration of saturation when above 5°C (r= 0.88) and with duration of total saturation (r= 0.87). The colour index is useful to evaluate soils for various land uses.
Compiling a field manual from overhead photographs for estimating crop residue cover
Authors: Molloy J. M. , Moran C. J.
Published: February 2007

Abstract. A method is presented for compiling a manual for the estimation of crop residue cover in the field. The crop residue is a combination of standing stubble and the straw remaining on the ground after harvest. Field assessment of crop residue is important so that management decisions may be made in the field. Such decisions include selection of cultivation or sowing machinery, irrigation scheduling (for crusting materials), soil temperature control and grazing of crop residue. The manual consists of a graded set of colour photographs, taken from an overhead boom, and a sampling rate nomogram to determine the number of 1 m quadrats required in a given field to estimate the cover with a predetermined level of error. Two methods for calibration of the photographs are compared: (a) projection of slides onto a screen with manual counting, and (b) digital image analysis of the photographs. Image analysis is efficient, rapid and gives less error than counting from the projections because many more points are counted. The use of the manual in the field is described. It is an inexpensive piece of equipment for the field agronomist or farmer, and gives a reliable, rapid and semi‐quantitative estimate of residue cover.
Strength and deformation of agricultural soil: measurement and practical significance
Authors: Kirby J. M.
Published: February 2007

Abstract. Soil has a finite strength to resist permanent volume change and permanent shear deformation. When the stresses imposed on the soil are of a sufficient magnitude to overcome the strength, then the deformation falls into one of two regimes. At low stress ratios (ratio of normal stress to maximum past stress) the soil expands when sheared and at high stress ratios it compresses. The maximum past stress in a field soil is the pre‐consolidation stress. The pre‐consolidation stress is the compressive stress greater than which compression is considerable and permanent.

These regimes of soil deformation behaviour are consistent and predictable under a wide range of conditions. They are described by the critical state concept, which can usefully be applied to soil management. Management decisions can be based on whether the stresses imposed by a particular operation result in high or low stress ratios. This governs whether the soil will deform permanently or not (for compaction damage), expand on shear (tillage) or compress on shear (preparation of rice paddy soils). The change in permeability and structure can also be predicted from the deformation regime.
The value of fertilizer, surface applied and injected sewage sludge to vegetation established on reclaimed colliery spoil suffering from regression
Authors: Michael N. , Bradshaw A. D. , Hall J. E.
Published: February 2007

Abstract. A 2‐year field experiment assessed the effectiveness of fertilizer, surface applied and injected liquid digested sewage sludge in increasing yields from reclaimed but regressing pasture on colliery spoil. At the first harvest, surface applications of sewage sludge gave the largest yields, although only a third of total fertilizer nitrogen (N) had been applied at this stage of the experiment. The greatest yields in the first year were given by fertilizer treatments which included the highest level of applied N, and large surface applications of sludge.

Surface applications of sludge on plots that were ripped gave the largest residual yields in the second year of the experiment. The percentage cover of clover was inversely related to the amount of nitrogen applied. A study of plant roots indicated that soil injection supplies sludge at too great a depth to benefit grass.

Taken overall the results confirm that the regression of pastures established on reclaimed colliery spoil is primarily caused by lack of nitrogen and phosphorus. But the effect of compaction in decreasing root growth, and therefore the ability of the grass to take up nutrients, is also apparent.
Prototype agricultural land evaluation systems for Canada: I. Overview of systems development
Authors: MacDonald K. B. , Brklacich M.
Published: February 2007

Abstract. Information on land resources and the capacity of land to support agricultural production is a prerequisite for the formation of sound agricultural policies. This paper summarizes Canadian experiences in developing national and regional land evaluation systems. Potential users expected the system to estimate the degree to which changes in biophysical and socio‐economic conditions would alter options for land use and production, and to provide a context for more detailed analysis.

A broad‐scale land evaluation system was designed to serve the needs identified by representative user groups. Two prototype systems were developed from available information to test the major features of the system design. Neither prototype was complete; one was national in extent and capable of addressing issues of national and provincial importance, the other covered a sub‐provincial area but allowed for more detailed evaluation of the effects of soil modifying processes. A full range of applications was demonstrated using one or other of the prototype systems. As a result of this project, the broad‐scale land evaluation system design was improved and verified, ongoing research and data collection activities were adjusted to ensure that they meet the needs of a macroscale land evaluation system, and approaches were developed to overcome problems of land evaluation system development.
Influence of fertilized short‐rotation forest plantations on nitrogen concentrations in groundwater
Authors: Bergström L. , Johansson R.
Published: February 2007

Abstract. The influence of intensively fertilized short‐rotation forest plantations on nitrogen concentrations in groundwater was studied by piezometer readings and water sampling over a two‐year period in a sandy field growing willow (Salix spp.) and other species. The mineral‐N content of the unsaturated zone was measured in soil samples collected to 0.9 m depth. Although piezometer readings suggested that deep groundwater could be affected, the concentrations of nitrate‐N and ammonium‐N were usually less than 1 mg per litre. There was also little mineral‐N in the unsaturated zone, except for occasional peaks in the topsoil (0–30 cm) after application of fertilizer. We conclude that there is little risk of nitrogen contamination of groundwater in intensively cultured tree stands receiving up to 150 kg N/ha/yr as fertilizer. This is probably because willow can take up water and nitrogen from deep parts of the soil profile.
The impact of cultivation practice and wheelings on runoff generation and soil erosion on the South Downs: some experimental results using simulated rainfall
Authors: Robinson D. A. , Naghizadeh R.
Published: February 2007

Abstract. The quantitative effects of different cultivation practices and wheelings on the generation of runoff and soil loss on the South Downs were assessed experimentally with a small drip‐type rainfall simulator and rainfall intensities of 42.5 and 23.3 mm/h. Runoff volumes generated by different cultivation practices and between wheeled and non‐wheeled areas were significantly different. Amounts of soil lost from different cultivation treatments and from wheelings were less consistent. Less runoff and erosion occurred from shallow cultivated land than from conventionally ploughed and cultivated land. Runoff is further increased by rolling ploughed land after drilling and along tramlines compressed by wheelings. Under high intensity rainfall, considerable runoff can be generated from stubble, especially from wheeled areas.
Monitoring of water erosion on arable farms in England and Wales, 1989–90
Authors: Chambers B. T. , Davies D. B. , Holmes S.
Published: February 2007

Abstract. Water erosion was recorded between mid‐October and mid‐December 1989 in 31 out of 73 erosion‐susceptible arable fields being monitored in England and Wales. Most fields were drilled to winter cereals. Tramlines and wheelings were the factors most commonly linked with initiation of erosion, particularly where runoff was concentrated on valley floors or headlands. Lack of crop cover (< 15%) was also an important factor at a number of sites; 25–30% ground cover was generally sufficient to protect the soils from erosion. Erosion was initiated by rainfall events of 15 mm or more in a 24 h period, with a maximum intensity greater than 4 mm/h. A large erosion event in south‐west England was associated with 33 mm of rainfall in 4.25 h, with a maximum intensity of 22 mm/h.
Soil variability in map units delineated by aerial photo‐interpretation: a case study in Anambra State, Nigeria
Authors: Akamigbo F.O.R. , Igwe C.A. , Oranekwulu S.C.
Published: February 2007

Abstract. The variability of five soil series developed in sedimentary formations in southeastern Nigeria and mapped from aerial photographs was investigated in relation to texture, soil reaction, organic carbon, total nitrogen, exchangeable bases, exchangeable acidity, cation exchange capacity and available phosphorus. Air photo delineation of the five soil series was based on terrain physiography alone. Most of the soil series were very variable in available phosphorus, but the coefficients of variation for other soil properties were less than the 33%) threshold adopted for within‐series homogeneity critical for land use management. Soil series mapping at 1:50000 scale based on aerial photographs is therefore a cheap, rapid technique, which gives a satisfactory basis for land management to improve productivity and decrease soil degradation in Nigeria.
Use of a shrub (Medicago arborea) to control water erosion on steep slopes
Authors: Andreu V. , Rubio J.L. , Cerni R.
Published: February 2007

Abstract. The effect of Medicago arborea on erosion on a burnt area was studied in experimental plots near Valencia, Spain, between 1989 and 1992. Its growth and development was studied, and its effect was compared with the natural vegetation (matorral) and bare soil. Medicago decreased soil loss by 41.7% and runoff by 25.7% compared with bare soil. However, under natural vegetation soil loss was 27.5% less than under Medicago.
Climate‐based estimates of forage yields in the prairie region of western Canada
Authors: Bootsma A. , Boisvert J.B. , Dumanski J.
Published: February 2007

Abstract. A forage model (FORYLD) was used to estimate average potential (constraint‐free) yields (By) and yields under rainfed conditions (Bya) of alfalfa and wheatgrasses for the prairie region of Western Canada. Yield estimates were determined using 30‐year climatic means (monthly values) and assumed available water‐holding capacities (AWC) of soils ranging from 50 to 280 mm as inputs to the model. Calculations were made for 252 areas or zones known as Agroecological Resource Areas (ARAs) for the region. Estimates of By for alfalfa ranged from over 17.5 t/ha, in areas where three cuts of alfalfa were feasible if the crop were fully irrigated, to less than 10 t/ha in some northern ARAs where restricted length of the growing season limited potential to only one cut. For wheatgrasses By ranged from 15 to 17.5 t/ha in most areas where two cuts are possible. Estimates of Bya for alfalfa, based on the predominant AWC for soils in each ARA, ranged from less than 2 t/ha in the driest portion of the prairie region to more than 8 t/ha in the more humid areas. Yields of wheatgrasses were very similar to those of alfalfa in the driest zones but slightly more in some of the more humid regions. Effects of varying soil AWC on yield estimates are presented for the major soil groups of the prairies.
Effects of ‘Agri‐SC’ soil conditioner on soil structure and erodibility: some further observations
Authors: Fullen M.A. , Tye A.M. , Cookson K.E.
Published: February 2007

Abstract. In field and laboratory experiments the conditioner‘Agri‐SC’has shown improvements in the structure of loamy sand soils in east Shropshire, UK. It resulted in statistically significant decreases in soil bulk density values and increases in soil porosity and aggregate stability. Further experiments are in progress on both loamy sand and silt loam soils.
Decomposition of crop residues under laboratory conditions
Authors: Saviozzi A. , Scagnozzi A. , Riffaldi R. , Levi‐Minzi R.
Published: February 2007

Abstract. A laboratory study was designed to provide data on the decomposition of rape, sunflower and soyabean residues put in bags buried in soil. The residue bags were removed at intervals during 1 year, analysed for remaining total mass, organic and water‐soluble C, water‐soluble sugars, as well as for volatile acids and phenolic compounds. The decomposition dynamics of total mass, total organic and water‐soluble organic C, and water‐soluble sugars were reproduced satisfactorily by a double‐exponential model of the first‐order type.

Generally, no large differences in the rate and magnitude of decomposition among the residues were observed; the greatest losses of both total mass and chemical components occurred in the first month of the study, during which the volatile acids and phenolic compounds disappeared almost completely. Of the three residues, soyabean showed the lowest loss of organic carbon, losing 66% of the original content over the course of the year compared with 73 and 75% for sunflower and rape, respectively.
Soil erosion from a single rainstorm over an area in East Lothian, Scotland
Authors: Frost C.A. , Speirs R.B.
Published: February 2007

Abstract. An area of about 24 km2 in arable East Lothian, Scotland, was examined for soil erosion by water following a severe rainstorm in October 1990. Significant erosion was found in only 10 fields out of 26.5 in an area where topography, soils and cropping suggest a high erosion risk. Doubt is cast on some assessments of the widespread risk of significant soil erosion by water in arable areas of the UK.
Cheese whey effects on surface soil hydraulic properties
Authors: Lehrsch G. A. , Robbins C. W.
Published: February 2007

Abstract. Whey, the liquid byproduct of cheese production, can improve the physical condition of sodic soils or those susceptible to erosion by increasing their aggregate stability. The effects of whey on soil hydraulic properties, however, are not known. In this experiment, we used tension infiltrometers to determine whey effects on infiltration rates of water (at suctions ≥ 30 mm of water) and unsaturated hydraulic conductivities of Ap horizons of a Portneuf silt loam (coarse‐silty, mixed, mesic Durixerollic Calciorthid) after a winter wheat crop. In the summer of 1993 near Kimberly, ID, USA, liquid whey was flood‐applied at either 0, 200,400, or 800 t/ha to plots planted to wheat the previous September. At suctions of 60 and 150 mm, infiltration rates decreased linearly by about 0.7 μm/s with each additional 100 t/ha of whey applied. As whey applications increased, hydraulic conductivities at 60 mm suction increased slightly but as applications exceeded 400 t/ha decreased significantly. We concluded that summer whey applications up to 400 t/ha would not adversely affect surface hydraulic properties.
Nitrate leaching after cut grass/clover leys as affected by time of ploughing
Authors: Djurhuus J. , Olsen P.
Published: February 2007

Abstract. Nitrate leaching after one year of a cut grass/clover ley was measured in two succeeding years to investigate how the postponing of ploughing leys from early to late autumn or spring, in combination with spring or winter cereals affected leaching of nitrate. The experiment was conducted as three field trials, two on a coarse sandy soil and one on a sandy loam soil. For calculation of nitrate leaching, soil water samples were taken using ceramic suction cups. The experiments started in spring in a first year ley and ended in spring three years later. Total nitrate leaching for the three year periods for each trial ranged between 160–254 and 189–254 kg N/ha on the coarse sand and 129–233 kg N/ha on the sandy loam. The results showed that winter wheat (Triticum aestivum L.) did not have the potential for taking up the mineralized N in autumn after early autumn ploughing of grass/clover leys, and that the least leaching was generally found when ploughing was postponed until spring, and when winter rye (Secale cereale L.) was grown as the second crop rather than spring barley (Hordeum vulgare L.). Nevertheless, leaching was generally high in the winter period even when winter rye was grown. On these soil types ploughing out should be postponed, whenever possible, to spring. Crop systems that maximize the utilization of mineralized N and thereby minimize nitrate leaching need to be further developed. Based on N balances, the data were further used to estimate the biological N fixation by the clover.
The effect of crop, N‐level, soil type and drainage on nitrate leaching from Danish soil
Authors: Simmelsgaard S. E.
Published: February 2007

Abstract. Nitrate leaching measurements in Denmark were analysed to examine the effects of husbandry factors. The data comprised weekly measurements of drainage and nitrate concentration from pipe drains in six fields from 1971 to 1991, and weekly measurements of nitrate concentration in soil water, extracted by suction cups at a depth of 1 m, from 16 fields in 1988 to 1993. The soils varied from coarse sand to sandy clay loam.

The model used for analysing the data was: Y= exp (1.136–0.0628 clay+ 0.00565N +crop) D0.416, with R2= 0.54, where Y is the nitrate leaching (kg N/ha per y), clay is the % clay in 0‐25 cm depth (%), N is the average N‐application in the rotation (kg/ha/y) and D is drainage (mm/y). The most important factor influencing leaching was the crop type. Grass and barley undersown with grass showed low rates of leaching (17‐24 kg/ha/y). Winter cereal following a grass crop, beets, winter cereals following cereals and an autumn sown catch crop following cereals showed medium rates of leaching (36‐46 kg/ha/y). High rates of leaching were estimated from winter cereals following rape/peas, bare soil following cereals and from autumn applications of animal manure on bare soil (71‐78 kg/ha/y). Estimates of leaching from soil of 5, 12 and 20% clay were 68, 44 and 26 kg/ha/y, respectively. Leaching was estimated to rise significantly with increasing amounts of applied N.

The model is suitable for general calculations of the effects of crop rotation, soil type and N‐application on nitrate leaching from sandy soil to sandy clay loarns in a temperate coastal climate.
Influence of cultivation on the distribution of phosphorus in three soils from NE Scotland and their aggregate size fractions
Authors: Maguire R. O. , Edward A. C. , Wilson M. J.
Published: February 2007

Abstract. The effect of cultivation on the P properties of whole soils and aggregate sizes separated from them was investigated for soil developed on three types of parent material. Cultivation, with associated fertilizer additions, increased both the total soil P content and extractable P of the whole soils. When the soils were separated into aggregate sizes (< 2, 2‐52, 53‐150 and 151 2000 μm), total soil P and resin extractable P increased with decreasing aggregate size. Water extractable inorganic P exhibited the opposite trend, while concentrations of water extractable organic P were similar from each aggregate size. Eroded aggregates can adsorb P or release P to solution, the extent of which will be dependent upon a combination of soil attributes and the prevailing solution conditions. The resulting equilibrium P concentration (EPC) of the eroded material will be markedly different from that of the whole soil. By increasing the P content, particularly of the smaller sized aggregates it is likely that the EPC of the eroded material would favour greater P desorption.
Mitigation options for diffuse phosphorus loss to water
Authors: Withers P. J. A. , Jarvis S. C.
Published: February 2007

Abstract. Agriculture contributes significant loads of P to surface waters. The reductions in these diffuse P inputs necessary to help prevent eutrophication problems and/or assist in the restoration of water quality will require controls over both nutrient inputs and their subsequent transport in land runoff. Specific mitigation options include nutrient budgeting, input management, soil conservation, land use management and the establishment of riparian, and other buffer zones. The variable nature of diffuse P loss suggests that the best approach to control is through integrated management at a range of scales. Critical control concepts at the farm level include targeting source areas adequately, maintaining P input loading rates within recommended limits and avoiding high‐risk management actions. Since eutrophication is a natural phenomenon and with potential conflicts with the need to meet production targets and/or minimize loss of other nutrients (N), some assessment of acceptable levels of P loss, of cost effectiveness of options and some prioritization of goals are necessary to find optimal solutions. As the requirements of individual waterbodies differ, these solutions need to be site specific and their successful adoption requires an appreciation by farmers of the importance of minimizing agricultural P loss both as individuals and collectively within a catchment.
What Proportion of Stroke Is Not Explained by Classic Risk Factors?
Authors: Ionita Catalina C. , Xavier Andrew R. , Kirmani Jawad F. , Subasini Dash , Divani Afshin A. , Qureshi Adnan I.
Published: February 2007

Ischemic stroke is a complex entity with multiple etiologies and variable clinical manifestations. The most frequent cause of stroke is atherosclerosis of cerebral vasculature followed by cardioembolism. Two thirds of strokes are explained by identifiable risk factors. Age, hypertension, and nonvalvular atrial fibrillation are by far the most frequent and well documented ones. Approximately 5% of strokes are caused by conditions other than atherosclerosis or heart disease, i.e., cervical arteries dissections, nonatherosclerotic vasculopathies, infectious or systemic vasculitis, and collagen vascular diseases. In spite of a thorough diagnostic evaluation, 30% of strokes remain cryptogenic, i.e., no specific cause is identified and the classic risk factors are not present. Identification of unknown environmental or genetic risk factors should be the subject of further research.
Prevalence of Cardiovascular Risk Factors in Selected Samples of Schoolchildren—Socioeconomic Influence
Authors: Guimarães Isabel C.B. , Guimarães Armênio C
Published: February 2007

Few data are available regarding the prevalence of cardiovascular risk factors in schoolchildren in Brazil. Weight, height, body mass index, blood pressure, and serum cholesterol were determined in 366 students, from 6–12 years of age, 209 (57.1%) from a private school and 157 (41.9%) from a public school, 187 (51.1%) female, aged 8.4±1.7 years. Prevalence of the risk of being overweight was 14.8%, being overweight/obese 13.1%, and presenting with elevated cholesterol (≥170 mg/dL) was 28.1%, particularly at the private school: 21.5% vs. 5.7% for the risk of being overweight (p<0.001), 17.2% vs. 7.6% for being overweight/obese (p<;0.01), 41.8% vs. 10.2% for cholesterol ≥170 mg/dL (p<0.001), and 14.8% vs. 1.3% for cholesterol ≥200 mg/dL (p<0.001), respectively. The results showed a high prevalence of risk factors among these school children, especially among private students.
Substantial Weight Gain During Adulthood: The Road to Bariatric Surgery
Authors: McCullough Peter A. , Sandberg Keisha R. , Miller Wendy M. , Odom Jacqueline S. , Sloan Kevin C. , De Jong Adam T. , Nori Katherine E. , Irving Sarah D. , Krause Kevin R. , Franklin Barry A.
Published: February 2007

We sought to examine the relationship of body mass index (BMI) at age 18 years with the degree and rate of rise in body weight during adulthood among the morbidly obese. We evaluated 196 patients with a standard medical history form and a structured interview with questions regarding weight at age 18 years. The study included 40 (20.4%) men and 156 (79.6%) women. The mean BMI was 50.2±8.0 kg/m2, range 37.0–80.0 kg/m2. Based on self‐reported weight, 133 (67.9%) were overweight/obese (BMI >25 kg/m2) and 68 (34.7%) were obese (BMI ≥30 kg/m2) at age 18 years. The distribution of cumulative weight gain was normal with a mean of 60.8±23.7 kg. There was a positive relationship (r=0.36, p<0.0001) between BMI at age 18 years and BMI in adulthood at a mean of 44±10.6 years. Independent predictors for cumulative adult weight gain were BMI at age 18 years (p<0.0001); women (p<0.0001); African Americans (p=0.05). These data suggest that modestly overweight young adults can have excessive weight gains during adult life, resulting in morbid obesity and high rates of obesity‐related comorbidities.
Pharmacotherapy Review: Calcium Channel Blockers
Authors: Sica Domenic A.
Published: February 2007

As a drug class, calcium channel blockers encompass a heterogeneous group of compounds with distinctive structures and pharmacologic characteristics. These agents are widely used in the treatment of hypertension, chronic coronary ischemia, and/or supraventricular arrhythmias. Much of the early debate alluding to increased cardiovascular risk associated with calcium channel blocker use has been silenced by an array of outcomes trials that show these drugs to be both safe and effective in reducing hard cardiovascular end points. The most common side effects associated with calcium channel blockers are vasodilatory in nature and include a non‐volume‐dependent form of peripheral edema, flushing, and headache. Despite the sometimes discomforting side effects seen with calcium channel blocker therapy, their robust blood pressure‐lowering effect makes them an important component of most multidrug regimens used for blood pressure control.
Is the Development of Diabetes With Antihypertensive Therapy a Problem?—Pro
Authors: Verdecchia Paolo , Angeli Fabio , Reboldi Gianpaolo , Gattobigio Roberto
Published: February 2007

Some questions about new‐onset diabetes (NOD) must still be completely addressed: 1) its incidence; 2) the possible association between NOD and some classes of antihypertensive drugs; and 3) its prognostic impact. It is well known that diuretics and β blockers can increase plasma glucose and, in available hypertension trials, diuretics and β blockers caused a higher incidence of NOD than new antihypertensive drugs. NOD heralds a high risk of major cardiovascular events, but the absolute difference between old and new drugs was too small to significantly drive the differences in cardiovascular event rates between the two groups of treatment. This evidence suggests a judicious use of drugs more frequently associated with NOD in subjects at high risk of diabetes (impaired fasting glucose, overweight, family history of diabetes, low high‐density lipoprotein cholesterol levels). The lowest effective dose of these drugs should be used, plasma glucose should be checked periodically, and concomitant lifestyle measures to prevent diabetes should be implemented with resolution.
Impact of Blood Pressure vs. Glycemic Factors on Target Organ Damage in Patients With Type 2 Diabetes Mellitus
Authors: Eguchi Kazou , Ishikawa Joji , Hoshide Satoshi , Ishikawa Shizukiyo , Shimada Kazuyuki , Kario Kazuomi
Published: February 2007

The hypothesis that three measures of target organ damage in type 2 diabetics would be more closely related to blood pressure (BP) than to glycemic factors was tested by recording 24‐hour ambulatory BP and glycosylated hemoglobin. The prevalence of silent cerebral infarcts with brain magnetic resonance imaging, left ventricular mass index with cardiac ultrasonography, and albuminuria in 244 asymptomatic diabetics (mean age, 65.4±9 years; 122 men and 122 women; hypertension, 73%) were evaluated. Multivariate analysis showed that age (standard partial regression coefficient: β=0.299; p<0.001), duration of hypertension (β=0.176; p=0.007), and 24‐hour systolic BP (β=0.195; p =0.004) were significantly associated with the number of silent cerebral infarcts, but glycosylated hemoglobin (β=0.104; p =0.109) and duration of diabetes were not. Left ventricular mass index was associated with 24‐hour systolic BP (β=0.377; p<0.001) and male sex (β=0.172; p=0.019). Presence of albuminuria was significantly associated with 24‐hour systolic BP (β=0.209; p=0.003), duration of diabetes (β=0.154; p=0.022), cholesterol (β=0.132; p=0.042), and insulin use (β=0.150; p=0.026). In conclusion, all three measures of target organ damage were related to 24‐hour BP, but only albuminuria was related to glycosylated hemoglobin in type 2 diabetics. BP may be more important than glycemic factors for predicting future cardiovascular complications