bluuebunny/crossref_metadata_2025_split huggingface dataset:
Recent trends in soil pH and nutrient status in England and Wales
Authors: Skinner R. J. , Church B. M. , Kershaw C. D. 
Published: February 2007

Abstract. Results of the Representative Soil Sampling Scheme between 1978 and 1988 show that soil acidity remains widespread, particularly in Wales, and suggest that the proportions of grassland with low pH increased during this period in the traditional grassland areas of England and Wales.Average soil nutrient levels changed little over the decade. However, at least one in five grassland fields are likely to suffer yield restrictions because of shortage of soil P or K (index 0). One in four arable fields were found to be at index 1 for K, indicating that many crops are being grown at potassium levels which can be described as borderline. On the other hand, 22% of arable crops were grown at phosphate index levels in excess of 3, so phosphate savings could be made on many crops. Texture and calcium carbonate levels and their relationships with nutrient levels are also examined.
Bypass flow and leaching of nitrogen in a Kenyan Vertisol at the onset of the growing season
Authors: Smaling E. M. A. , Bouma J. 
Published: February 2007

Abstract.Bypass flow and concurrent leaching of nitrogen were studied on a Vertisol in south‐western Kenya under rangeland and bare, manually tilled cropland. Showers of 30 mm/hr were simulated, causing bypass flow of 47–62% in rangeland topsoils and 19–49% in cropland topsoils. Volumetric water contents after experimentation increased from 28 to 35% and from 24 to 38%, respectively, for the two land‐use types.In rangeland samples up to 3.4 kg N/ha was found in the leachate of unfertilized soil. With a fertilizer application of 50 kg N/ha, up to 5.7 kg N/ha was lost from a pre‐wetted soil, and more than 20 kg N/ha from dry soil. In cropland topsoils up to 2.2 kg N/ha was lost from unfertilized soil, and only up to 2.9 kg N/ha from both dry and prewetted fertilized soil. Although Vertisols are often linked with excess water, the phenomenon of bypass flow can cause water stress to crops in their early growth stages. Nitrogen leaching losses were large from dry grassland, but prewetting helped to decrease them. On intensively cultivated cropland there was little nitrogen leaching; the tilled topsoil was able to retain most of the supplied nitrogen.
A comparison of qualitative and quantitative physical land evaluations, using an assessment of the potential for sugar‐beet growth in the European Community
Authors: Van Lanen H. A. J. , Van Diepen C. A. , Reinds G. J. , De Koning G. H. J. 
Published: February 2007

Abstract. Qualitative and quantitative physical land evaluations differ in their technical procedures, i.e. use of expert knowledge versus process‐orientated simulation models. This paper compares the results of both procedures using the growth potential for sugar‐beet in the European Community. Qualitative procedures give suitability expressions, such as land being well suited or moderately suited for a given land use. Less than 30% of EC land was found to be well suited or moderately suited under water‐limited conditions. No quantitative expressions for the crop yield potential are, however, produced. The quantitative procedure describes suitability in terms of average crop yield and its temporal variability. Water‐limited and potential dry matter yields of sugar‐beet were estimated to range from 3.5 to 20 t/ha, and from 6 to 25 t/ha, respectively.Comparison of results of the qualitative and quantitative procedures for regions showed that the suitability classes obtained by the former can be characterized by different yield distributions derived from the latter. These yield assessments showed that results of qualitative land evaluation procedures aimed at assessing yield potential are meaningful only when they are linked to agroclimatic zones. The comparison also showed that some moderate restrictions, which often can be counteracted by adequate farm management, are not incorporated into the quantitative procedure.
MicroLEIS: A microcomputer‐based Mediterranean land evaluation information system
Authors: De la Rosa D. , Moreno J. A. , Garcia L. V. , Almorza J. 
Published: February 2007

Abstract. A computer‐based land evaluation information system (MicroLEIS) was developed for optimal use of agricultural and forestry land systems under Mediterranean conditions. Through an interactive procedure several land capability, suitability and yield prediction methods may be applied. The system addresses land evaluation at reconnaissance, semi‐detailed and detailed scales in an interrelated manner. Biophysical land evaluation methods are incorporated using empirical, scale‐appropriate models, which range from purely qualitative (reconnaissance) through semi‐quantitative (semi‐detailed) to quantitative (detailed). This software is helpful for teaching, research and development, predicting appropriate agroforestry land uses. Its use is illustrated by an example.MicroLEIS runs on IBM PC, XT, AT, or a compatible microcomputer with at least 128 kilobytes of RAM and a PC‐DOS or MS‐DOS version 2.0 or later operating system. The software package on double or high density diskettes can be obtained from the first author.
Effects of ‘Agri‐SC’ soil conditioner on the erodibility of loamy sand soils in East Shropshire, UK: preliminary results
Authors: Fullen M. A. , Tye A. M. , Pritchard D. A. , Reynolds H. A. 
Published: February 2007

Abstract. The effect of Agri‐SC’ soil conditioner on the erodibility of loamy sand soils has been investigated at the Hilton experimental site, Shropshire, since March 1988. Factors measured have included runoff and erosion, soil structure, crust strength, splash susceptibility, aggregate stability, soil micromorphological properties, response to compaction and penetrometer resistance.Treatment decreased runoff and erosion rates, bulk density, splash erosion, crust strength and penetrometer resistance, and increased pore space and aggregate stability. The effects on crust strength, aggregate stability and bulk density were statistically significant. The results suggest that applications of ‘Agri‐SC’ could have beneficial effects for soil conservation.
Effects of cropping system and rates of nitrogen in animal slurry and mineral fertilizer on nitrate leaching from a sandy loam
Authors: Thomsen I. K. , Hansen J. F. , Kjellerup V. , Christensen B. T. 
Published: February 2007

Abstract. Leaching of nitrate from a sandy loam cropped with spring barley, winter wheat and grass was compared in a 4‐year lysimeter study. Crops were grown continuously or in a sequence including sugarbeet. Lysimeters were unfertilized or supplied with equivalent amounts of inorganic nitrogen in calcium ammonium nitrate (CAN) or animal slurry according to recommended rates (1N) or 50% above recommended rates (1.5N).Compared with unfertilized crops, leaching of nitrate increased only slightly when 1N (CAN) was added. Successive annual additions of 1.5N (CAN) or 1N and 1.5N (animal slurry) caused the cumulative loss of nitrate to increase significantly. More nitrate was leached after application of slurry because organic nitrogen in the slurry‐was mineralized.With 1N (CAN) the leaching losses of nitrate were in the following order: continuous spring barley undersown with Italian ryegrass < continuous ley of perennial ryegrass < spring barley in rotation and undersown with grass < perennial ryegrass grown in rotation = winter wheat grown in rotation < sugarbeet in rotation < continuous winter wheat < continuous barley < bare fallow.At recommended levels of CAN (1N), cumulative nitrate losses over the four years were similar for the crops when grown in rotation or continuously. When crops received 1.5N (CAN) or animal slurry, nitrate losses from the crops grown continuously exceeded those from crops in rotation. Including a catch crop in the continuous cropping system eliminated the differences in nitrate leaching between the two cropping systems.
Nitrogen cycling and losses from dairy farms
Authors: Jarvis S. C. 
Published: February 2007

Abstract. The concern over leakage of nitrate into waters and loss of other forms of N to the environment demands an appraisal of N flows within complete systems. The grassland N cycle is complex, with interactive controls over fluxes and transformations, and has the potential for considerable losses. Although there are data from experimental systems, a total comprehension of flows is not yet possible.Intensive dairy farming has a number of opportunities for leaks. A ‘model’ system in SW England has an annual input of 25.6 tonnes of N: of this only 20% is transferred into protein or milk, a further 46% is lost to the wider environment, 34% is as yet unaccounted for and much is recycled. Recent research has provided new techniques to decrease losses. To meet the joint requirements of production and environmental concerns we need to consider N flows and supplies on an integrated, whole farm basis, and to take better account of mineral N in the soil profile in relation to current crop demand, local climate and past sward management.
Bioavailable potassium in river‐bed sediments and release of interlayer potassium in irrigated arid soils
Authors: Rahmatullah B.Z. Shaikh , Gill M.A. , Salim M. 
Published: February 2007

Abstract. Crop responses to applied potassium fertilizers are erratic in many arid and semi‐arid soils. The potassium supplying potential of river‐bed sediments and release of interlayer potassium from eleven alkaline soils were measured in two separate experiments. Sediments from the Chenab and Ravi Rivers in Pakistan were exhausted of potassium by successively growing wheat, maize, mungbean, and wheat in them for a total of 200 days, using Hoagland solution to supply optimum amounts of other nutrients. Cumulative plant dry matter yield was significantly greater on the Chenab sediments. The quantities of potassium supplied to plants from the sediments of the two rivers were also significantly different.Interlayer potassium was extracted for 1230 minutes from a Udic Haplustalf (Pindorian series) by twelve different solutions each with the same electrolyte content (100 cmol). The sodium adsorption ratios (SAR) of the solutions were adjusted to 5, 10, 25, and 50, each with Ca: Mg ratios of 25:75, 50: 50 or 75:25, using solutions of sodium, calcium and magnesium chloride. The potassium released from the soil was inversely related to solution SAR. Increasing proportions of magnesium relative to calcium in solution favoured the release of potassium, except in the SAR 50 solution. Significantly different quantities of potassium were extracted by various solutions. Maximum potassium (442 mg/kg) was extracted by SAR 5 solution with a Ca: Mg ratio of 25:75. Interlayer potassium subsequently removed by this solution from 11 alkaline soils ranged from 407 to 499 mg/kg. The potassium released from all but three of the soils was related to their clay content (r= 0.72; n= 8). The release of potassium from the soils followed the Elovich function. The intercept (X1) and slope (X2) estimated for the function was related to potassium released (y) by the equation: y=−1.13 + 2.74X1−0.014X2 (r= 0.998; n= 8)The results imply that river sediments treated with irrigation water containing magnesium and sodium ions can contribute substantial amounts of available potassium for plant growth.
Water treatment sludge: a potential plant growth medium
Authors: Skene T.M. , Oades J.M. , Kilmore G. 
Published: February 2007

Abstract. The disposal of water treatment sludge produced when turbid water is treated with flocculants (alum and polyDADMAC) and filtered for clarification is becoming increasingly expensive in South Australia. The physical and chemical properties of the sludge suggest that it might be used as a plant growth medium, and a glasshouse experiment compared the growth and elemental composition of broad beans in both alum and polyDADMAC sludge applied at different rates.Dry matter production differed significantly between treatments. Poly + Fertilizer (F) and Poly 4%+ F produced the most dry matter. The Alum + F treatment produced significantly less dry matter than the Poly + F treatment but it was not significantly different from the control. The difference in plant growth between the pure poly and pure alum treatments resulted from increased availability of the fertilizer phosphorus in the poly sludge and the supply of some potassium and nitrogen by the poly sludge. Fertilizer was required for optimum plant growth. Greater rates of fertilizer may be required if alum sludge is to be used as a growth medium, than if poly sludge is used.There was no evidence that aluminium toxicity would be a problem if water treatment sludges are used as growth media. The physical properties of the sludges (i.e. water holding capacity, drainage characteristics and structural stability) are probably more important than their inherent nutrient levels, although poly sludge does supply some nitrogen and does not fix phosphorus to the same extent as alum sludge.
Rock fragments I. Their effect on runoff, erosion and soil properties under field conditions
Authors: Moustakas N.C. , Kosmas C.S. , Danalatos N.G. , Yassoglou N. 
Published: February 2007

Abstract.The effects of different sizes, amounts, and positions of rock fragments on soil properties and erosion were studied in experimental plots (10 treatments including bare soils and soils under natural vegetation, with 3 replicates each) installed on a hillslope.Over five events, the largest amounts of runoff were from bare soils containing abundant rock fragments, either partially embedded on the surface or incorporated in the upper part of the soil. Stoneless soils gave smaller amounts, and the smallest runoffs were measured on soils under natural vegetation. Generally, large rock fragments (cobbles) caused greater runoff than smaller fragments (coarse gravel). However, soils with appreciable amounts of coarse gravel on the surface generated considerable runoff under rainfalls of low intensity and long duration, but smaller amounts at greater rainfall intensities.Sediment loss was greater from soils with cobbles than from soils containing coarse gravel; vegetation greatly decreased sediment loss from both.In a 12‐month period, the organic matter content of the soils decreased by 15.5 to 23.0%, decreasing soil aggregate stability. The organic matter content was greater in the collected sediments than in the soil.
Potential climate change effects on the distribution of agricultural grassland in England and Wales
Authors: Rounsevell M.D.A. , Brignall A.P. , Siddons P.A. 
Published: February 2007

Abstract. The spatial distribution of agricultural grassland in England and Wales has been assessed using a land evaluation model applied to information describing soils, climate and topography on a 5 × 5 km grid. The model calculates land suitability for grassland from assessments of trafficability/poaching risk and yield class. The spatial distribution of agricultural grassland was modelled for a 30 year climatic baseline (1941–1970) and for incremental changes in temperature and proportional changes in precipitation relative to that baseline.Model estimates for the current distribution of grassland suitability agree well with observed data of actual grassland distribution. The best suited land occurs in south west England, Wales, the Welsh borders and Cheshire with fragmented areas of well suited land in north west England and on the Pens and Humberhead levels.The climatic sensitivity analysis suggests that grassland production in England and Wales is resilient to small perturbations in mean temperature (up to +2°C) and precipitation (±10%). The effect of increasing temperature by 1°C is almost completely offset by precipitation increases of 10% resulting in little change to the distribution of grassland suitability. However, greater temperature changes (+ 4°C) have a major influence on the ability of land to support intensively managed grassland because of increased drought stress. Results indicate that a change in the climate comparable with current best estimates for the future would benefit grassland on good quality land at higher altitudes.
The influence of organic nitrogen mineralization on the management of agricultural systems in the UK
Authors: Shepherd M.A. , Stockdale E.A. , Powlson D.S. , Jarvis S.C. 
Published: February 2007

Abstract. The understanding of nitrogen mineralization is central to providing good advice to ensure that nitrogen (N), from whatever source, is utilized by crops as efficiently as possible to minimize pollution. We have reviewed how mineralization is accounted for in current advice. It is clear that there is at least a qualitative understanding of the effects of soil and crop management on N mineralization and N supply, which has enabled the development of Codes of Good Agricultural Practice and fertilizer recommendations systems, based on sound scientific principles. However, to refine advice there is a need for a better quantitative understanding.Although soil organic matter (SOM) is a major source of N for crops, we are unable adequately to predict fertilizer requirement as affected by mineralization of SOM. Nitrogen returns from crop residues can vary considerably between fields; the provision of better field specific advice is restricted by our inability accurately to quantify this variability. The qualitative controls on the amount and timing of N release from ploughed grass are known, but better quantification of mineralization/immobilization over both the short‐ and long‐term and better understanding of the relationship with sward age, inputs and management are essential. Much N can also be released from pasture and lost to the environment, especially where long‐term leys have been grazed and there is a need to quantify the changing balance of mineralization and immobilization with the age of sward and N input. Whilst the overall principle of cultivation affecting mineralization is well known and appreciated, little is known about the mechanisms and quantification is only possible for a comparison of such extremes as ploughing and direct drilling.
Evaluating the land use potential of gypsiferous soils from field pedogenic characteristics
Authors: Verheye W. H. , Boyadgiev T. G. 
Published: February 2007

Abstract. Although gypsiferous soils cover approximately 100 million ha in the world, it is only in the past two decades that their pedogenic and agronomic properties have been better understood and their classification improved. There is still no method to assess adequately their production potential.This paper focuses on gypsum accumulation forms as diagnostic criteria for a rapid soil suitability appraisal in the field. Pseudomycelia, gypsum spots, powdery coatings and other localized in situ precipitations usually indicate soils with less than 15% gypsum. Depending on their intensity and depth of occurrence in the root zone, they define a soil environment which is suitable for semi‐sensitive and semi‐tolerant crops. Continuous gypsum accumulations characterize soils or horizons with high (e.g. more than 25%) gypsum contents, and these can be used only for tolerant crops.The land use potential of gypsiferous soils is primarily determined by: (a) the depth of the impermeable layer, (b)the gypsum content within the root zone, and (c) the crop tolerance level. A method is proposed to assess the land suitability of gypsiferous soils on the basis of these criteria.
Estimation of N2‐fixation by grass–white clover mixtures in cut or grazed swards
Authors: Watson C. A. , Goss M. J. 
Published: February 2007

Abstract. Formulation of nitrogen balances on farms requires accurate information on all inputs of the nutrient. N2‐fixation by legumes, particularly forage legumes, is an important input which is difficult to measure. Simple regression models have been established from the literature for predicting N2‐fixation by grass–white clover (Trifolium repens) mixtures using dry matter yields.Linear relationships were obtained between the N2‐ fixation (Nfix) and the extra dry matter production of mixed swards (Md) compared with pure grass swards. Nitrogen fixation was given by Nfix= A + 0.067Md where A is the intercept having a value of 6.8 for cut swards and ‐168.1 for grazed swards. A common slope was adopted because the F statistics showed that slopes fitted separately were not significantly different. The value of the negative intercept represents the supply of N to the grazed sward from soil and excreta‐derived N. The regression equation for the cut sward gave reasonable predictions (r2= 0.953) of values of N2‐fixed for experimental data not used in establishing the relationship. For grazed grass, the approach over‐estimated the N2‐ fixation by an average of 15%.
Soil and land use effects on phosphorus in six streams draining small agricultural catchments in Scotland
Authors: Hooda P. S. , Moynagh M. , Svoboda I. F. , Thurlow M. , Stewart M. , Thomson M. , Anderson H. A. 
Published: February 2007

Abstract. Phosphorus concentrations and outputs have been compared and contrasted in six small agricultural catchments in the west and northeast of Scotland. The loss of P from soils to stream waters was more from catchments with intensive dairy cattle farming in the west than from the less intensively stocked/arable catchments in the northeast, with striking differences being seen between the two regions. In the northeast, intensive animal farming caused less P loss in drainage water than arable management.Larger mean annual concentrations were seen in the west (0.076‐0.142 mg PO4‐P/l as molybdate‐reactive phosphate–MRP) compared with the northeast (0.012‐0.025 mg PO4‐P/l), a feature caused by the combination of limited P‐retention in the western Gleysols and smaller inputs to the largely‐podzolic northeastern catchments. Stream concentrations were decreased by dilution during winter storm flows and increased during summer baseflow and at the beginning of soil rewetting in autumn.
Lower or higher doses for prophylactic platelet transfusions: results of a meta‐analysis of randomized controlled trials
Authors: Cid Joan , Lozano Miguel 
Published: February 2007

BACKGROUND: There are conflicting data regarding the optimal platelet (PLT) dose to transfuse prophylactically to patients with thrombocytopenia. A meta‐analysis has been performed to summarize the results of different randomized controlled trials (RCTs).STUDY DESIGN AND METHODS: RCTs reported through December 2005 were retrieved; five of them met the criteria for meta‐analysis. Weighted mean difference (WMD) of posttransfusion PLT count increment (×109/L) and transfusion interval (days) and summary odds ratio (OR) of bleeding in higher PLT dose group (HDP) versus lower PLT dose group (LDP), according to the authors, were calculated across studies.RESULTS: The use of HDP was associated with an increase in the transfusion interval (WMD, 1.04 days; 95% confidence interval [CI], 0.89‐1.19; p < 0.00001) when compared with the use of LDP. When the studies that guaranteed the ABO compatibility of the PLT transfusions were combined, the use of HDP was statistically associated with an increase in the posttransfusion PLT count increment when compared with the LDP group (WMD, 23.6 × 109/L; 95% CI, 18.28 × 109 to 28.92 × 109/L; p < 0.00001). When bleeding was studied, data were available in only three studies and the hypothesis of homogeneity was rejected, in 4 of 10 subgroups analyses.CONCLUSION: Few RCTs have addressed the issue of PLT dose for transfusion. It is shown that the transfusion of higher doses of PLTs is statistically associated with an increase in the transfusion interval and in the posttransfusion PLT count increment. A well‐designed study of enough power is essential to establish the most effective and efficient dose for prophylactic PLT transfusions.