bluuebunny/crossref_metadata_2025 huggingface dataset:
Release of Cholecystokinin‐Like Immunoreactivity in the Frontal Cortex of Conscious Rats as Assessed by Transcerebral Microdialysis: Effects of Different Depolarizing Stimuli
Authors: Vallebuona F. , Paudice P. , Raiteri M.
Published: August 2010

Abstract: The release of cholecystokinin‐like immunoreactivity (CCK‐LI) from the frontal cortex of freely moving rats has been studied using a transcerebral microdialysis technique coupled to a radioimmunoassay procedure. Basal levels of CCK‐LI in the dialysate were above detection limits (2.4 ± 0.7 pg/20 min; n = 8). High‐K+ media evoked CCK‐LI overflow in a concentration‐dependent manner. The threshold concentration was 50 mM KCI. The peak overflow evoked by 100 mM K+ amounted to 42.7 ± 2.8 pg/20 min (n = 6); it was totally Ca2+ dependent but insensitive to 1 μM tetrodotoxin. Infusion of 4‐aminopyridine (1 mM; 20 min) evoked an overflow of CCK‐LI (32 ± 2.3 pg/ 20 min; n = 4), wnich was totally Ca2+ dependent and tetrodotoxin sensitive. Depolarization with 100 μg/ml of veratrine (20 min) provoked a CCK‐LI overflow (62.2 ± 10 pg/20 min; n = 6), which was also blocked by tetrodotoxin or by the absence of Ca2+ ions. The CCK‐LI material collected under basal conditions or during veratrine infusion consisted essentially of CCK octapeptide sulfate. The veratrine‐induced CCK‐LI overflow did not change significantly when the infusion time was prolonged to 100 min. A second 20‐min stimulus with 100 μg/ml of veratrine applied 200 min after a first 20‐min stimulus evoked a barely significant CCK‐LI overflow. These data suggest that one single 20‐min stimulus with 100 μg/ml of veratrine may be sufficient to deplete the CCK‐LI releasable stores and that >200 min are required to replenish the depleted CCK‐containing vesicles. Taken together the data allow us to conclude that the physiology and the pharmacology of CCK release can be adequately studied in vivo by brain microdialysis.
Parent perspectives of therapy services for their children with physical disabilities
Authors: Egilson Snaefridur Thora
Published: August 2010

Scand J Caring Sci; 2011; 25; 277–284
 
Parent perspectives of therapy services for their children with physical disabilities

Background:  Children who have physical disabilities typically attend occupational and physical therapy services on a regular basis. The importance of being family centred when providing services to children with a disability has been highlighted in recent years. Thus, it was considered important to gather the opinions of parents towards the services their child receives.

Aim:  To explore the perspectives of parents of children with physical disabilities to occupational and physical therapy services provided to their child.

Method:  Open interviews were conducted with 17 parents (14 mothers and three fathers) of children aged 7–13, selected through a purposeful sample. Data analysis was based on an inductive approach.

Results:  Nine categories emerged and were organized under three main headings: The role of the therapist, service location and arrangements, and characteristics of good service. Although several positive remarks were made, many parents in this study were poorly informed of intervention goals and what took place during therapy sessions. Most parents wished for mutual respect, joint decision‐making in planning intervention, and collaboration with the therapy services. The aspiration for active but manageable roles that did not demand a burdensome amount of the parents’ time and energy was evinced. The parents became increasingly critical of the services, as their children grew older. They placed emphasis on services being offered in their local community, and that more specialized service should be centralized, especially for the children with the most complex needs.

Conclusions:  The results reflect the importance of the needs and wants of the parents and children being respected. Thus, parents should play an active role in defining priorities and strategies for implementation. The results also indicate that therapists need to put more thought into the conditions and environment of the child instead of focusing solely on underlying issues connected to their impairments.
Strategy for clinical evaluation and screening of sudden cardiac death relatives
Authors: Ferrero‐Miliani Laura , Holst Anders Gaarsdal , Pehrson Steen , Morling Niels , Bundgaard Henning
Published: August 2010

Sudden cardiac death (SCD) may be the first and final manifestation of several heart diseases. In the young, SCD is often caused by a hereditary cardiac disease. As the most frequently seen inherited cardiac diseases have an autosomal‐dominant pattern of inheritance, half of the first‐degree relatives are at risk of having or developing the same disease. Therefore, screening of these high‐risk relatives is a rational approach to reduce the incidence of SCD. To offer family screening and counseling, the cause of death should be carefully established. Autopsy is only performed in a limited number of cases. We advocate for systematic autopsies in SCD, because positive findings are crucial for choosing the optimal screening program for the relatives. A negative autopsy makes identification of at‐risk population difficult. However, this finding also provides clues to the cardiologist, because a limited number of inherited cardiac diseases associated with SCD are without any structural changes. In other cases, the autopsy may reveal noncardiac causes of death, which is also important for reassuring the relatives. However, in cases with no autopsy or negative findings, thorough clinical examinations and selective genetic screening of relatives may identify a likely diagnosis in more than 50% of affected families. There is a need for consensus regarding routine evaluation of SCD cases and the ethical and legal framework related to postmortem testing. We propose an algorithm that narrows the diagnostic possibilities in apparently healthy relatives of young SCD victims. Molecular autopsy may play an important role.
Nitrate leaching loss following application of organic manures to sandy soils in arable cropping.
Authors: Beckwith C.P. , Cooper J. , Smith K. A. , Shepherd M.A.
Published: August 2010

Abstract.Experiments were set up at two sites to measure nitrogen (N) leaching loss from applications of separated pig/cattle slurry and cattle farmyard manure(FYM), during winters 1990/91–1993/94 (site A) and from broiler litter and FYM, during winters 1990/91–1992/93 (site B). The manures were applied at a target rate of 200 kg ha‐1total N during the autumn and winter to overwinter fallow or top dressed onto winter rye. The total N in leachate was calculated from leachate N concentrations, in samples collected using ceramic cups buried at 90 cm, and an estimate of drainage volume. Nitrogen losses were greatest following manure applications in September, October and November but losses following applications in December or January were not significantly elevated above those from untreated controls. Losses were consistently lower from FYM than from broiler litter or separated slurry. The presence of a cover crop (winter rye) significantly reduced overall N leaching compared with the fallow, but only reduced the manure N leaching losses at one site during one winter when a high proportion of drainage occurred late. The incorporation of a nitrification inhibitor (DCD) with manures applied in October did not significantly reduce the manure N leaching.
Nitrogen and phosphorus in runoff from grassland with buffer strips following application of fertilizers and manures
Authors: Heathwaite A.L. , Griffiths P. , Parkinson R.J.
Published: August 2010

Abstract. We examined whether nitrogen (N) and phosphorus (P) export was enhanced from grassland receiving inorganic fertilizer and manures typical of intensive livestock production. Buffer strips were included in the study to determine if they could reduce nutrient export. Hillslope plots receiving granular inorganic fertilizer, liquid cattle slurry and solid cattle manure (FYM) were compared using rainfall simulation for 4 storms on consecutive days at 22 mm h‐1 and 35 minutes duration. The plots were hydrologically isolated in a randomized block layout of 4 treatments × 3 replicates and measured 30 × 5m; the upper 20m received either fertilizer, slurry or FYM, while the lower 10 m acted as an unfertilized grass buffer strip. Nitrogen and P export in surface runoff from grassland receiving inorganic fertilizer exceeded that from FYM or slurry treatments; concentrations up to46mgN1‐‐1 and 15 mgP1–1 were recorded.

Sixty eight % and 62% of the N from FYM and slurry respectively, was exported in organic form. Seventy four % (FYM) and 39% (slurry) of the P was in particulate or dissolved organic form. The buffer strip reduced N export in surface runoff by 94% and P export by 98% from inorganic fertilizer plots. A 75% reduction in N export was recorded from the buffer zone below slurry plots but only a 10% reduction in P, with most P remaining in the particulate or dissolved organic fraction. There was no significant difference in N export from the buffer zone between the inorganic fertilizer treatment and the untreated control.
The measurement and analysis of denitrification rates obtained using soil columns from river marginal wetlands
Authors: Flynn N. , Gardner P.J. , Maltby E.
Published: August 2010

Abstract.Soil cores from river marginal wetlands from three sites in the UK (Torridge and Severn catchments), sampled and restrained in PVC piping, were flooded with dilute aqueous potassium nitrate. Half of the cores were sterilized prior to flooding to destroy the denitrifying bacteria. The change in nitrate concentration in the flood‐water was measured over time. It is argued that the observed nitrate depletion rates (from 1.2 to 4.7 kg ha−1d−1) is the result of microbially‐mediated denitrification. The results show the method to be a simple and direct procedure for the assessment of spatial variation in nitrate‐sink capacity. The depth of the denitrifying layer at the soil–water interface was confirmed to be of the order of a few mm only. A one‐dimensional model for the diffusive flux in the flooded soil was developed which, on differentiation, gave a predictive expression for denitrification rate in terms of the effective soil diffusion coefficient for nitrate, the flood‐water depth and concentration, and the thickness of the microbially active zone.
A field study of gross rates of N mineralization and nitrification and their relationships to microbial biomass and enzyme activities in soils treated with dairy effluent and ammonium fertilizer
Authors: Zaman M. , Di H.J. , Cameron K.C.
Published: August 2010

Abstract. Gross N mineralization and nitrification rates were measured in soils treated with dairy shed effluent (DSE) (i.e. effluent from the dairy milking shed, comprising dung, urine and water) or ammonium fertilizer (NH4Cl) under field conditions, by injecting 15N‐solution into intact soil cores. The relationships between gross mineralization rate, microbial biomass C and N and extracellular enzyme activities (protease, deaminase and urease) as affected by the application of DSE and NH4Cl were also determined. During the first 16 days, gross mineralization rate in the DSE treated soil (4.3–6.1 μg N g−1 soil day−1) were significantly (P 14;< 14;0.05) higher than those in the NH4Cl treated soil (2.6–3.4 μg N g−1 soil day−1). The higher mineralization rate was probably due to the presence of readily mineralizable organic substrates in the DSE, accompanied by stimulated microbial and extracellular enzyme activities. The stable organic N compounds in the DSE were slow to mineralize and contributed little to the mineral N pool during the period of the experiment. Nitrification rates during the first 16 days were higher in the NH4Cl treated soil (1.7–1.2 μg N g−1 soil day−1) compared to the DSE treated soil (0.97–1.5 μg N g−1 soil day−1). Soil microbial biomass C and N and extracellular enzyme activities (protease, deaminase and urease) increased after the application of the DSE due to the organic substrates and nutrients applied, but declined with time, probably because of the exhaustion of the readily available substrates. The NH4Cl application did not result in any significant increases in microbial biomass C, protease or urease activities due to the lack of carbonaceous materials in the ammonium fertilizer. However, it did increase microbial biomass N and deaminase activity. Significant positive correlations were found between gross N mineralization rate and soil microbial biomass, protease, deaminase and urease activities. Nitrification rate was significantly correlated to biomass N but not to the microbial biomass C or the enzyme activities. Stepwise regression analysis showed that the variations of gross N mineralization rate was best described by the microbial biomass C and N.
Nitrate Sensitive Areas: a study of large scale control of nitrate loss in England
Authors: Lord E.I. , Johnson P.A. , Archer J.R.
Published: August 2010

Abstract. The Pilot Nitrate Sensitive Areas Scheme was set up in England in 1990 to test measures aimed at reducing nitrate losses from agricultural land. Ten groundwater catchments were chosen to typify the geology and farming of areas where nitrate concentrations in abstracted water were high. Voluntary and compensated controls on farming, based on recent research, were introduced. Scheme membership was for 5 years from 1990 or 1991, and 86% of the agricultural land entered the Scheme. On all farms entering the Scheme, manure and fertilizer use were restricted and green cover crops were required over winter (Basic Scheme). Additional payments were available for conversion of arable land to zero or low‐input grassland (Premium Scheme). Intensive pig and poultry farmers were assisted with the costs of transporting manure for spreading over a wider area. The most effective changes were improved management of livestock manures, especially of the very large local quantities from housed pig or poultry units; conversion of arable land to low‐input grassland; and use of cover crops. There were no indications of reduced crop yields but some requirements increased costs and management complexities. Estimates based on both model calculations and measurements indicated that nitrate losses from agricultural land decreased by about 30%, with considerable variation between areas.
Nutrient fluxes from a soil treatment process for pig slurry
Authors: Martinez J. , Peu P.
Published: August 2010

Abstract. The effects of pig slurry applications to a hydrologically isolated field treatment plant (at Solepur) were studied over a period of eight years. Thirty repeated doses, averaging 160 m3 ha−1 were applied from April to October of each year (1991–1995), to reach a total application of 4930 m3 ha−1. All slurry samples were analysed for their total solids (TS), macronutrient (C, N, P, K, Ca) and micronutrient (Cu, Zn) content. In total, 284 tonnes of total solids (57 t TS ha−1 yr−1), 115 tonnes of carbon (23 t C ha−1yr−1), 24.5 tonnes of nitrogen (4900 kg N ha−1 yr−1), 7964 kg of phosphorus (1593 kg P ha−1 yr−1), 16 518 kg of potassium (3304 kg K ha−1 yr−1), 183 kg copper (37 kg Cu ha−1 yr−1) and 266 kg zinc (53 kg Zn ha−1 yr−1) were applied to the soil. Thus, this site provides an opportunity to assess the balance and to examine the long‐term behaviour of nutrients under conditions of intensive land application of pig slurries or similar effluents.

The main nutrient fluxes through the soil‐water system were determined for each element. Over 40% of the total carbon applied was retained by the soil. About 25% of the slurry nitrogen applied remained in the soil profile and 12.5% was leached through the drainage water as nitrate. Most of the slurry phosphorus applied was retained in the soil profile either as P‐Dyer extractable (83%), or as total soil phosphorus (112%); <0.01% was found in the drainage water. Forty‐three per cent of the potassium applied in the slurry was recovered from the soil profile and 15% was recovered in the drainage water. Most of the copper (62%) and zinc (74%) applied in the slurry remained in the soil as EDTA extractractable forms; very low percentages (0.05% and 0.6% respectively) were found in the drainage water.
Persistence of denitrifying enzyme activity in refrigerated and air‐dried Cambisols
Authors: SS˘imek M. , Webster E.A.
Published: August 2010

Abstract.Denitrifying enzyme activity (DEA) declined to a greater extent and was more variable in soils stored air‐dried for 6 months than after storage at 4 °C. DEA was greatest in fertilized soils. The relative differences in DEA between soils were maintained after storage at 4 °C. We suggest that storage at 4 °C is more appropriate than air‐drying.
Direct and residual effects of pulp and paper mill sludge on crop yield and soil mineral N
Authors: Vagstad N. , Broch‐Due A. , Lyngstad I.
Published: August 2010

Abstract. Paper sludge composted or stored in static piles for six months was compared to raw and lime‐stabilized sludge in a three‐year pot experiment (loam) and a four‐year field experiment (silt loam) at rates of up to 40 t DM ha‐l. The original sludge contained equal amounts of fibre sludge and biological sludge, mixed with bark in 1:1 ratio to improve the structure. The N content in composted sludge (1.30%) was markedly lower than that of the uncomposted piles (1.98%), indicating significant loss during composting. The yield results were generally inversely proportionate to the C:N ratios of the sludges applied. Sludge from the uncomposted piles gave significant grain yield increases in the year following sludge application, while the other sludge types gave variable results. In the residual years there was, generally, a small but positive effect on yield from all the sludge types. The N and P content in grain generally increased with sludge application, but only the higher rates gave statistically significant increases. Sludge application also increased the Zn content in grain, while Mn, B and Cu was less affected. The increase in Cd content was very small. The 40 t ha‐l sludge rate tended to increase the residual mineral N in soil at the field site and thus the risk of nitrate leaching.
Comparing the spatial predictions of soil organic matter determined by two laboratory methods
Authors: Frogbrook Z.L. , Oliver M.A.
Published: August 2010

Abstract. The most common way of assessing soil organic matter content is by loss on ignition, which is both simple and inexpensive. This method tends to overestimate organic matter content because additional weight losses occur during ignition. An alternative, more expensive and time‐consuming method for determining soil organic matter content is by an acid dichromate oxidation. This paper compares the results of applying these methods to soil on different parent materials in two arable fields. Summary statistics and correlation coefficients showed that there were consistent relationships between the two sets of values: the stronger was for the sandy soil and the weaker was for the clay loam. This relationship can be used to improve the accuracy with which soil organic matter content is known while using fewer of the expensive measurements and more of the inexpensive ones. Two approaches to prediction were compared: the geostatistical method of cokriging, and simple linear regression. These were used to predict organic matter determined by an acid dichromate oxidation from the loss on ignition. The estimates from cokriging were more accurate but the method requires the spatial correlation to be modelled reliably. The regression results showed it to be a valuable and practical approach. Using the information from nine carefully selected sampling sites a regression line could be fitted that was representative of the full data.
Effects of reforestation and deforestation on soil properties in humid mountainous areas: a case study in Wolong Nature Reserve, Sichuan province, China
Authors: Liu S.L. , Fu B.J. , Lü Y.H. , Chen L.D.
Published: August 2010

Abstract. Natural secondary succession, forest planting and agricultural practices after deforestation affect soil properties in many ways. During the last 50 years, land uses have greatly changed in the mountainous areas in southwestern China as the result of deforestation and cultivation. A study was initiated in Wolong Nature Reserve, Sichuan province to elucidate the complex relationships in a humid mountainous region. Soil properties under six typical land use types (natural forest, grassland, shrub, secondary forest, cultivated land and reforested land) were compared. Significant differences between land uses were found for soil bulk density (BD), total nitrogen (TN), soil organic carbon (SOC), available phosphorus (AP) and available potassium (AK). Cultivated land had the lowest levels for most soil properties compared to other land uses and shrubland had a higher SOC, TN and available nitrogen (AN) than other land uses. Soils under grassland and shrub contained the greatest carbon mass (TC). Further studies on reforested land indicated that soil properties could be changed by length of reforestation. The SOC and TN in particular showed a linear relationship with years since reforestation. The results suggested that in an area of China where the climate favours secondary succession, ‘leave nature as it is’ is a better choice than the policy ‘change farmland to forest land ‘, especially for the mountainous regions where there is lack of labour and financial support.
Evaluating an integrated approach to catchment management to reduce soil loss and sediment pollution through modelling
Authors: Verstraeten G. , Van Oost K. , Van Rompaey A. , Poesen J. , Govers G.
Published: August 2010

Abstract. Soil erosion and sediment delivery cause many environmental problems posing a substantial financial burden upon society. Policy makers therefore look for a strategy to minimize their impact. The spatial nature of soil erosion and sediment delivery, as well as the variety of possible soil conservation and sediment control measures, requires an integrated approach to catchment management. To evaluate such management, a spatially distributed soil erosion and sediment delivery model is necessary. Such a model (WaTEM/SEDEM) was applied to three agricultural catchments in Flanders (Belgium). The model was first used to identify where the measures to control soil loss should be taken. Secondly, a scenario analysis was used to select the most effective set of techniques. The findings showed that soil conservation measures taken in fields are not only effective in reducing on‐site soil loss, but also in drastically reducing sediment yield. Off‐site sediment control measures appear to be much less effective in reducing sediment yield than previously thought. The results also suggest that data from field experiments cannot be extrapolated to a catchment scale.
Nitrate leaching losses and their control in a mixed farm system in the Cotswold Hills, England
Authors: Allingham K.D. , Cartwright R. , Donaghy D. , Conway J.S. , Goulding K.W.T. , Jarvis S.C.
Published: August 2010

Abstract. Nitrate leaching was measured for four years at the Royal Agricultural College ‘s Coates Farm in the Cotswolds, England. Coates is a typical Cotswold mixed farm with thin, well‐drained calcareous soils especially prone to leaching. Over the duration of this study there were dairy, sheep and arable enterprises on the farm. A ‘Farm Gate’ nitrogen (N) budget was constructed. Small 120 m × 20 m ‘farmlets’ were sited in ten fields across the farm, covering all parts of the rotation, as the sites for detailed measurements. Each farmlet received the same management as the rest of the field in which they were situated. Using ceramic probes inserted to 60 cm, soil water was sampled every two weeks throughout the winter drainage season. The annual drainage varied from 135 mm under grassland in 1996/7 to 600 mm under cereals in 1998/9. Average N losses by leaching were determined mostly by rainfall and were 65 kg N ha–1 yr–1, accounting for 25% of the N inputs. Especially leaky parts of the rotation were the ploughing out of a lucerne ley and the grazing of stubble turnips with sheep, both typical Cotswold farm practices. The research highlights some of the difficulties in developing practicable, profitable management practices to decrease nitrate losses.
Is the productivity of organic farms restricted by the supply of available nitrogen?
Authors: Berry P.M. , Sylvester‐Bradley R. , Philipps L. , Hatch D.J. , Cuttle S.P. , Rayns F.W. , Gosling P.
Published: August 2010

Abstract. This paper reviews information from the literature and case studies to investigate whether productivity in organic systems is restricted by the supply of available N during the major phases of crop growth. Organic systems have the potential to supply adequate amounts of available N to meet crop demand through the incorporation of leys, N rich cash crop residues and uncomposted manures. However, this is seldom achieved because leys are only incorporated once every few years and organically produced crop residues and manures tend to have low N contents and slow mineralization rates. N availability could be improved by delaying ley incorporation until spring, applying uncomposted manures at the start of spring growth, transferring some manure applications from the ley phase to arable crops, preventing cover crops from reaching a wide C:N ratio and better matching crop type with the dynamics of N availability.
Managing soil organic matter – implications for soil structure on organic farms
Authors: Shepherd M.A. , Harrison R. , Webb J.
Published: August 2010

Abstract. This paper reviews current understanding of soil structure, the role of soil organic matter (SOM) in soil structure and evidence for or against better soil physical condition under organic farming. It also includes new data from farm case studies in the UK. Young SOM is especially important for soil structural development, improving ephemeral stability through fungal hyphae, extracellular polysaccharides, etc. Thus, to achieve aggregate stability and the advantages that this conveys, frequent input of fresh organic matter is required. Practices that add organic material are routinely a feature of organically farmed soils and the literature generally shows that, comparing like with like, organic farms had at least as good and sometimes better soil structure than conventionally managed farms. Our case studies confirmed this. In the reviewed papers, SOM was generally larger on the biodynamic/organic farms because of the organic additions and/or leys in the rotation. We can therefore hypothesize that, because it is especially the light fraction of SOM that is involved in soil structural development, soil structure will improve in a soil to which fresh organic residues are added regularly. Thus, we argue it is not the farming system per se that is important in promoting better physical condition, but the amount and quality of organic matter returned to a soil.
Soil fertility in organic farming systems – fundamentally different?
Authors: Stockdale E.A. , Shepherd M.A. , Fortune S. , Cuttle S.P.
Published: August 2010

Abstract. Soil fertility is defined as the ability of a soil to provide the conditions required for plant growth. It is a result of the physical, chemical and biological processes that act together to provide nutrients, water, aeration and stability to the plant, as well as freedom from any substances that may inhibit growth. Within this definition, it is useful to distinguish between those components of fertility which change relatively slowly, perhaps over the course of a rotation, or in some cases, decades, and the more immediate contribution from materials such as fertilizers and manures. The term ‘inherent fertility’ is used to describe these more stable characteristics, while recognising that they are, to a large extent, products of soil management. We conclude that, although nutrient management in organically managed soils is fundamentally different to soils managed conventionally, the underlying processes supporting soil fertility are not. The same nutrient cycling processes operate in organically farmed soils as those that are farmed conventionally although their relative importance and rates may differ. Nutrient pools in organically farmed soils are also essentially the same as in conventionally managed soils but, in the absence of regular fertilizer inputs, nutrient reserves in less‐available pools will be of greater significance.
Soil salinity and its distribution determined by soil sampling and electromagnetic techniques
Authors: Herrero J. , Ba A.A. , Aragüés R.
Published: August 2010

Abstract. Diagnosis of soil salinity and its spatial variability is required to establish control measures in irrigated agriculture. This article shows the usefulness of electromagnetic (EM) and soil sampling techniques to map salinity. We analysed the salinity of a 1‐ha plot of surface‐irrigated olive plantation in Aragon, NE Spain, by measuring the electrical conductivity of the saturation extract (ECe) of soil samples taken at 22 points, and by reading the Geonics EM38 sensor at 141 points in the horizontal (EMH) and vertical (EMV) dipole positions. EMH and EMV values had asymmetrical bimodal distributions, with most readings in the non‐saline range and a sharp transition to relatively high readings. Most salinity profiles were uniform (i.e. EMH=EMV), except in areas with high salinity and concurrent shallow water tables, where the profiles were inverted as shown by EMH > EMV, and by ECe being greater in shallow than in deeper layers. The regressions of ECe on EM readings predicted ECe with R2 > 84% for the 0–100 to 0–150 cm soil depths. We then produced salinity contour maps from the 141 ECe values estimated from the electromagnetic readings and the 22 measured values of ECe. Owing to the high soil sampling density, the maps were similar (i.e. mean surface‐weighted ECe values between 3.9 dS m−1 and 4.2 dS m−1), although the electromagnetically estimated ECe improved the mapping of details. Whereas soil sampling is preferred for analysing the vertical distribution of soil salinity, the electromagnetic sensor is ideal for mapping the lateral variability of soil salinity.
The effect of incorporating slurries on the transport of faecal coliforms in overland flow
Authors: Quinton J.N. , Tyrrel S.F. , Ramos M.C.
Published: August 2010

Abstract. Rainfall simulation experiments on a laboratory soil flume were conducted to test the hypothesis that the incorporation of slurry into the soil would reduce bacterial transport in overland flow. Presumptive faecal coliform (PFCs) concentrations were higher in the runoff from the surface applied treatment than from the incorporated treatments. The transport of PFCs and organic sediment were strongly correlated, with values of r ranging from 0.72 to 0.91.
Impact of water percolation on nutrient leaching from an irrigated paddy field in Japan
Authors: Katoh M. , Iwata A. , Shaku I. , Nakajima Y. , Matsuya K. , Kimura M.
Published: August 2010

Abstract.We examined the effect on soil nutrient status and sustainability of water percolation through an irrigated paddy field in Japan, to the depth of drainage (40 cm). The difference between amounts of nutrients leached by percolation and those supplied by irrigation indicated that 25–130 kg ha−1Ca, 8–24 kg ha−1Mg, from −1 to 9 kg ha−1K, and 8–17 kg ha−1Fe, respectively, were lost each year from the 0–40 cm soil layer during rice cultivation, when the supply from fertilization and rainfall and the loss in grain harvest were not accounted for. When the supply of K from rainfall and the loss in grain harvest were taken into account, a total K loss of about 10 kg ha−1was estimated. The electrical neutrality of inorganic ions in the percolating water was always maintained. From these results we estimate that the amounts of exchangeable Ca and Mg in the soil to a depth of 40 cm would decrease by 50% within 50–260 and 30–100 years, respectively, if similar management were continued without fertilization. The total amount of carbon dioxide (ΣCO2) leached in percolating water during the period of rice cultivation was 120–325 kg C ha−1, which corresponded to 0.47–0.94% of the soil organic carbon to 40 cm depth.
Subsoil retention of organic and inorganic nitrogen in a Brazilian savanna Oxisol
Authors: Lehmann J. , Lilienfein J. , Rebel K. , do Carmo Lima S. , Wilcke W.
Published: August 2010

Abstract. Nitrogen (N) loss by leaching poses great challenges for N availability to crops as well as nitrate pollution of groundwater. Few studies address this issue with respect to the role of the subsoil in the deep and highly weathered savanna soils of the tropics, which exhibit different adsorption and drainage patterns to soils in temperate environments. In an Anionic Acrustox of the Brazilian savanna, the Cerrado, dynamics and budgets of applied N were studied in organic and inorganic soil pools of two maize (Zea mays L.) – soybean (Glycine max (L.) Merr.) rotations using 15N tracing. Labelled ammonium sulphate was applied at 10 kg N ha−1 (with 10 atom%15N excess) to both maize and soybean at the beginning of the cropping season. Amounts and isotopic composition of N were determined in above‐ground biomass, soil, adsorbed mineral N, and in soil solution at 0.15, 0.3, 0.8, 1.2 and 2 m depths using suction lysimeters throughout one cropping season. The applied ammonium was rapidly nitrified or immobilized in soil organic matter, and recovery of applied ammonium in soil 2 weeks after application was negligible. Large amounts of nitrate were adsorbed in the subsoil (150–300 kg NO3−‐N ha−1 per 2 m) matching total N uptake by the crops (130–400 kg N ha−1). Throughout one cropping season, more applied N (49–77%; determined by 15N tracers) was immobilized in soil organic matter than was present as adsorbed nitrate (2–3%). Most of the applied N (71–96% of 15N recovery) was found in the subsoil at 0.15–2 m depth. This coincided with an increase with depth of dissolved organic N as a proportion of total dissolved N (39–63%). Hydrophilic organic N was the dominant fraction of dissolved organic N and was, together with nitrate, the most important carrier for applied N. Most of this N (>80%) was leached from the topsoil (0–0.15 m) during the first 30 days after application. Subsoil N retention as both adsorbed inorganic N, and especially soil organic N, was found to be of great importance in determining N losses, soil N depletion and the potential of nitrate contamination of groundwater.
In‐field calibration of a dielectric soil moisture meter designed for use in an access tube
Authors: Whalley W.R. , Cope R.E. , Nicholl C.J. , Whitmore A.P.
Published: August 2010

Abstract. The in‐field calibration of a dielectric probe to measure soil water content is described. The probe uses an access tube analogous to that of the neutron probe. The dielectric constant was measured at soil depths of 10, 20, 30, 40, 60 and 100 cm. Cores of soil were then taken from the face of pits dug 30 cm from the access tube and their soil water contents determined by oven drying. The dielectric constant values measured by the probe were calibrated against water contents from these cores. We found that sensor depth needed to be included to achieve a good calibration model that explained 72% of the variance. It is argued that depth needs to be included because of artefacts introduced during the installation of the access tube.
Soils as carbon sinks: the global context
Authors: Smith P.
Published: August 2010

Abstract. Soil carbon sequestration could meet at most about one‐third of the current yearly increase in atmospheric CO2‐carbon, but the duration of the effect would be limited, with significant impacts lasting only 20–50 years. Coupled with this limited duration, increases in population and per‐capita energy demand mean that soil carbon sequestration could play only a minor role in closing the difference between predicted and target carbon emissions by 2100. However, if atmospheric CO2 concentrations are to be stabilized at reasonable levels (450–650 ppm), drastic reductions in carbon emissions will be required over the next 20–30 years. Given this, carbon sequestration should form a central role in any portfolio of measures to reduce atmospheric CO2 concentrations over this crucial period, while new energy technologies are developed and implemented. International agreements, such as the Kyoto Protocol, encourage soil carbon sequestration and could be used to formulate soil carbon sequestration polices. Such policies need to take account of other environmental impacts as well as political, economic and societal needs, so that they form part of a raft of measures encouraging sustainable development. Of the carbon sequestration options available, those of a ‘win–win’ nature, that is, those that increase carbon stocks at the same time as improving other aspects of the environment, and those that protect or enhance existing stocks (‘no regrets’ implementation) show the greatest promise in meeting these goals.
Effect of a legume cover crop (Mucuna pruriens var. utilis) on soil carbon in an Ultisol under maize cultivation in southern Benin
Authors: Barthès B. , Azontonde A. , Blanchart E. , Girardin C. , Villenave C. , Lesaint S. , Oliver R. , Feller C.
Published: August 2010

Abstract. Long term fallow is no longer possible in densely populated tropical areas, but legume cover crops can help maintain soil fertility. Our work aimed to study changes in soil carbon in a sandy loam Ultisol in Benin, which involved a 12‐year experiment on three maize cropping systems under manual tillage: traditional no‐input cultivation (T), mineral fertilized cultivation (NPK), and association with Mucuna pruriens (M). The origin of soil carbon was also determined through the natural abundance of soil and biomass 13C. In T, NPK and M changes in soil carbon at 0–40 cm were −0.2, +0.2 and +1.3 t C ha−1 yr−1, with residue carbon amounting to 3.5, 6.4 and 10.0 t C ha−1 yr−1, respectively. After 12 years of experimentation, carbon originating from maize in litter‐plus‐soil (0–40 cm) represented less than 4% of both total carbon and overall maize residue carbon. In contrast, carbon originating from mucuna in litter‐plus‐soil represented more than 50% of both total carbon and overall mucuna residue carbon in M, possibly due to accelerated mineralization of native soil carbon (priming effect) and slow mulch decomposition. Carbon originating from weeds in litter‐plus‐soil represented c. 10% of both total carbon and overall weed residue carbon in T and NPK. Thus mucuna mulch was very effective in promoting carbon sequestration in the soil studied.
A simple process‐based model for estimating ammonia emissions from agricultural land after fertilizer applications
Authors: Misselbrook T.H. , Sutton M.A. , Scholefield D.
Published: August 2010

Abstract. Fertilizer applications to agricultural land are a significant source of ammonia (NH3) emission to the atmosphere, accounting for approximately 10% of the total emissions from agriculture. Current estimates of emissions from fertilizer applications use ‘fixed’ emission factors. This paper describes a model in which the emission factors are expressed as a function of the important influencing variables: fertilizer type, soil pH, land use, application rate, rainfall and temperature. Total emission in 2002 for the UK were estimated by running the model for a ’standard UK‘ scenario, viz. 28.7 kt NH3‐N, which compares well with the UK inventory estimate of 30.4 kt NH3‐N. Differences exist in the estimates for specific fertilizer types, with the mean emission factor for urea applications to grassland, in particular, being lower by use of this model (13% compared with 23% of applied N for the UK inventory). Emission estimates were most sensitive to temperature and fertilizer type. Scenario testing showed that significant reductions in emission could be achieved by replacing urea with other forms of N fertilizer, by combining urea use with a urease inhibitor, or by modifying some management practices.
A packed lysimeter experiment to investigate the effect of surface sealing on hydrology and pesticide loss from the reconstructed profile of a clay soil
Authors: Heppell C.M. , Chapman A.S. , Bidwell V.J. , Kilfeather A.A.
Published: August 2010

Abstract. A laboratory experiment was designed to assess the impact of surface seal development on herbicide loss from a clay soil. The influence of surface sealing on herbicide loss through vertical macropores and lateral throughflow pathways was of particular interest. Losses of the phenylurea herbicide, isoproturon, increased from 0.025% to 0.5% of the total applied under sealed compared with unsealed conditions, as a result of two different mechanisms. First, an increased flow rate through the A horizon under the wetter, sealed conditions resulted in earlier initiation of, and hence a greater volume of, throughflow containing isoproturon in the lysimeters. Second, increased concentrations of isoproturon in macropore and throughflow under the sealed treatments were attributed to the physical and chemical characteristics of the surface seal. Localized reductions in infiltration capacity, changes in soil composition, and decrease in diffusion depth of herbicide within the surface seal are presented as possible mechanisms by which herbicide losses from the sealed soil lysimeters were enhanced.
Effects of different potassium fertilizers suitable for use in organic farming systems on grass/clover yields and nutrient offtakes and interactions with nitrogen supply
Authors: Fortune S. , Hollies J. , Stockdale E.A.
Published: August 2010

Abstract. In organic farming systems, fertilizing materials can be used when potassium (K) deficiency is shown, but such systems are dominantly nitrogen (N) limited and this is likely to affect crop utilization of K. The supply of K to grass/clover from a range of mineral and organically based K fertilizers and its interaction with N supply were studied in a greenhouse experiment. Sequential plant cuts were taken for yield and nutrient content determinations in crop and soil. Crop yields were limited by N: where N supply was increased either through the mineralization of N from organic materials (rapemeal, farmyard manure) or inorganic fertilizer, plant yields increased significantly. Grass/clover responded better to additional K where sufficient N was available. However, yield responses to K were generally small, even in the presence of adequate N. Of the different fertilizers, kali and MSL‐K increased yields above those of the control by less than 5%, sylvinite, DKSI and farmyard manure by 10–20%, and rapemeal and potassium sulphate by more than 25%. In all treatments, K offtakes in the grass/clover were considerably greater than fertilizer K inputs. The grass/clover showed an increased uptake of Na where insufficient K was available. However, the Mg content of the grass/clover was not adversely affected by K fertilizer application. Organic farmers need to consider the soil K status, the rotational nutrient budget, the supply of all nutrients in fertilizing materials and nutrient interactions to achieve effective K management in organic farming systems.
Nutrient acquisition and nitrate reductase activity of mycorrhizalRetama sphaerocarpaL. seedlings afforested in an amended semiarid soil under two water regimes
Authors: Caravaca F. , Alguacil M.M. , Díaz G. , Marín P. , Roldán A.
Published: August 2010

Abstract.We studied the effect of inoculation with three arbuscular‐mycorrhizal (AM) fungi (Glomus intraradicesSchenck & Smith,Glomus deserticola(Trappe, Bloss. & Menge) andGlomus mosseae([Nicol & Gerd.] Gerd. & Trappe) and the addition of composted sewage sludge on root nitrate reductase (NR, EC 1.6.6.1.) activity, mycorrhizal colonization, plant growth and nutrient uptake inRetama sphaerocarpaL. seedlings afforested in a semiarid, degraded Mediterranean soil under well‐watered and non‐watered conditions. Six months after planting, the mycorrhizal inoculation and the irrigation of plants had a strong effect on the growth parameters. The effect on plant growth was a negative interaction between plant irrigation and mycorrhizal inoculation and a positive interaction between plant irrigation and composted sewage sludge addition. The latter treatment had a significant, but moderate, effect on the growth but conferred no additional benefit when combined with mycorrhizal inoculation. Mycorrhizal inoculation, composted sewage sludge and irrigation had a significant effect on NR activity in roots and on foliar nutrients. The irrigation significantly increased the positive effect of composted sewage sludge on NR activity and the concentrations of foliar N and K. The effect of mycorrhizal inoculation on NR activity did not depend on the water regime. The effectiveness of mycorrhizal inoculation on the establishment and growth ofR. sphaerocarpaseedlings in these Mediterranean conditions was independent of water regime. The addition of composted sewage sludge was only effective when soil water was freely available. The combination of mycorrhizal inoculation and composted sewage sludge addition had no synergistic effect on plant growth.
Potentially mineralizable nitrogen from organic materials applied to a sandy soil: fitting the one‐pool exponential model
Authors: Cordovil C.M. d. S. , Coutinho J. , Goss M. , Cabral F.
Published: August 2010

Abstract. Over the last three decades there has been a great increase in the production of waste from urban, industrial and agricultural activity that could be recycled as a source of plant nutrients, and used to enhance soil quality. The use of these materials could partially offset the need for mineral fertilizers, giving both economic and environmental benefits. An incubation experiment was carried out using different organic waste materials applied to a Cambic Arenosol. Air‐dried soil was mixed with increasing amounts of composted solid municipal waste, secondary pulp‐mill sludge, hornmeal, poultry manure, solid phase from pig slurry, and composted pig manure, resulting in applications equivalent to 0, 40, 80, 120, 160 and 200 kg ha−1 of Kjeldahl nitrogen. The samples were incubated for 244 days under a controlled environment of 24 °C and 60% water holding capacity of the soil. The increasing amounts of waste applied always led to a greater amount of potentially available nitrogen present in the soil/waste mixture. Based on the proportion of their active N fraction, wastes were ranked: poultry manure>hornmeal>solid phase from pig slurry>composted pig manure>secondary pulp‐mill sludge>composted municipal solid waste. The results were well described by a one‐pool exponential mineralization model, and mineral N formation was proportional to the quantity of waste applied. Of the wastes tested, those from animal sources showed greater nitrogen mineralisation. Nitrification was rapid, and concentrations of ammonium nitrogen remained relatively small.
Perspectives on nutrient management in mixed farming systems
Authors: Watson C.A. , Öborn I. , Eriksen J. , Edwards A.C.
Published: August 2010

Abstract. Changes in agricultural subsidies in Europe and the ready availability of fertilizers have allowed a spatial decoupling of livestock and crop production. This has increased the flow of nutrients that occurs between farms compared to within individual farms. In terms of nutrient cycling, mixed farms provide the opportunity to re‐integrate aspects of agricultural production. The degree of integration between crop and livestock production is defined by the reliance on the use of home‐produced feed compared to imported feed, and is independent of intensity. Management of inputs and/or internal flows offers the scope to improve nutrient use efficiency (NUE) on mixed farms. Greatest uncertainties in calculating NUE are associated with variation in yield and composition of home‐produced feed, and consequent manure composition. Three key areas are addressed to highlight the interchange of nutrients (and risks for losses) between crop and livestock production; (i) the role of livestock diet in manipulating the amount and availability of manure nutrients; (ii) the impact of manure management on nutrient losses; and (iii) nutrient management through the integration of crops and livestock in rotations. While not all the associated issues are unique to mixed farming, these three areas all influence NUE.