bluuebunny/crossref_metadata_2025 huggingface dataset:
The biological and physical role of mulch in the rehabilitation of crusted soil in the Sahel
Authors: Mando A. , Stroosnijder L.
Published: August 2010

Abstract.During three consecutive years (1993–1995) a split‐plot design with three replications was used to study the biological and physical role of mulch in the improvement of crusted soil water balance and its productivity in the north of Burkina Faso. The main treatment was the use of an insecticide, to obtain plots with and without soil fauna (SF and NSF). The subsidiary treatment consisted of four mulch types randomly applied on subplots. These were straw ofPennisetum pedicellatumapplied at 3 t ha−1, woody material ofPterocarpus lucensapplied at 6 t ha−1and composite (woody material and straw) treatments applied at 4 t ha−1. In addition there was a control, with no mulch (bare plot). Data on soil faunal activity, runoff, sediment accumulation from wind blown soil, vegetation cover and vegetation dry matter yield were collected on all plots.

The biological activity (mainly termites) in mulched plots was the key element in the efficacy of mulching to rehabilitate crusted soil. Water infiltration and dry matter yield were statistically lower on NSF plots than on SF plots and runoff and dry matter yield were not different from the values obtained on bare plots. A significant correlation was found between runoff, all vegetation data and termite‐voids. Sediment accumulation due to the physical barrier of the mulch was not found to be a significant factor in the improvement of vegetation performance and the reduction of runoff.
Nitrate leaching in an organic dairy/crop rotationas affected by organic manure type, livestock densityand crop
Authors: Eriksen J. , Askegaard M. , Kristensen K.
Published: August 2010

Abstract. In dairy farming systems the risk of nitrate leaching is increased by mixed rotations (pasture/arable) and the use of organic manure. We investigated the effect of four organic farming systems with different livestock densities and different types of organic manure on crop yields, nitrate leaching and N balance in an organic dairy/crop rotation (barley–grass‐clover–grass‐clover–barley/pea–winter wheat–fodder beet) from 1994 to 1998. Nitrate concentrations in soil water extracted by ceramic suction cups ranged from below 1 mg NO3‐N l−1 in 1st year grass‐clover to 20–50 mg NO3‐N l−1 in the winter following barley/pea and winter wheat. Peaks of high nitrate concentrations were observed in 2nd year grass‐clover, probably due to urination by grazing cattle. Nitrate leaching was affected by climatic conditions (drainage volume), livestock density and time since ploughing in of grass‐clover. No difference in nitrate leaching was observed between the use of slurry alone and farmyard manure from deep litter housing in combination with slurry. Increasing the total‐N input to the rotation by 40 kg N ha−1 year−1 (from 0.9 to 1.4 livestock units ha−1) only increased leaching by 6 kg NO3‐N ha−1. Nitrate leaching was highest in the second winter (after winter wheat) following ploughing in of the grass‐clover (61 kg NO3‐N ha−1). Leaching losses were lowest in 1st year grass‐clover (20 kg NO3‐N ha−1). Averaged over the four years, nitrate concentration in drainage water was 57 mg l−1. Minimizing leaching losses requires improved utilization of organic N accumulated in grazed grass‐clover pastures. The N balance for the crop rotation as a whole indicated that accumulation of N in soil organic matter in the fields of these systems was small.
Soil S availability in upland pastures of NE Scotland: relationship of extractable soil S and soil respiration to soil and site characteristics
Authors: Donald D. , Chapman S.J. , Edwards A.C. , Atkinson D.
Published: August 2010

Abstract. The mean extractable sulphur (S) concentration in 315 upland topsoil samples collected in 1988/89 from beneath pasture in NE Scotland was 13 μg S g−1 (range 2–77 μg S g−1). More than two thirds of the samples had S concentrations less than that acceptable for productive soils. Continued decreases in atmospheric S inputs may have increased this proportion subsequently. The analysis of herbage S also indicated that two‐thirds of the samples were below 0.2% S. A ‘respirometric index’, namely CO2 produced during cellulose decomposition without added S as a percentage of that produced with added S, was significantly less than 100% in a quarter of the soils. Results of three different extraction procedures suggested that sulphate in the soils was present mainly as free plus adsorbed rather than precipitated forms. Soil extraction identified a significant non‐sulphate S fraction, presumably organic S. The variability in extractable S stemmed from a combination of geographical, depositional and local site and soil factors. Extractable S was significantly correlated with soil organic matter content and inversely with soil pH and together these factors explained 37% of the variability. While significant differences in mean concentrations between geographical area, soil association and drainage status were evident, no trends could be observed between the major soil subgroups or with altitude.
Replacement of soil and soil‐forming materials by loose tipping in reclamation to woodland
Authors: Moffat A.J. , Bending N.A.D.
Published: August 2010

Abstract. Four experiments studying ground preparation for the restoration of disturbed land to a woodland cover are described. They provide consistent evidence to suggest that methods of soil replacement which minimize compaction are preferable to conventional methods followed by deep ripping to relieve compaction induced in the placement operation. In addition, soil loosening using an excavator is more effective than that achieved by ripping. The research supports modern guidance which advocates ‘loose tipping’ as the best method of ground preparation for a woodland or forestry after‐use on sites reclaimed after dereliction or mineral extraction.
A survey of the production and use of animal manures in England and Wales. I. Pig manure
Authors: Smith K.A. , Brewer A.J. , Dauven A. , Wilson D.W.
Published: August 2010

Abstract. A survey was undertaken in 1996, by postal questionnaire sent to a stratified sample of 1500 pig producers in England and Wales; 576 (37%) responded. The survey provided data on manure production, manure storage and application strategies (timing, techniques and nutrient recycling to crops).

Total pig manure production, in England and Wales is estimated to be at about 10.03 m t per year, with about 45% as slurry and 55% as FYM, according to this survey, where calculations have been based on undiluted outputs of excreta. About 45% of slurry is stored in above‐ground tanks or earth‐banked lagoons. Above‐ground tanks most commonly held an amount of slurry equivalent to 3–6 months production, but earth‐banked lagoons were more variable in capacity and over 20% could hold more than 9 months production of slurry.

Annual statistics on fertilizer use indicate that farmers make little allowance for the nutrient content of manures. However, the results of this survey suggest that farmers generally make a genuine effort to allow for the nutrients applied, but that they currently fail to be assured by the advice available to them or their confidence is lacking for other technical reasons. Autumn represents the peak period for spreading, with 30% of slurry and 50% of FYM applied at that time.
Spatial patterns of nitrogen mineralization, fertilizer distribution and roots explain nitrate leaching from mature Amazonian oil palm plantation
Authors: Schroth G. , Rodrigues M.R.L. , D'Angelo S.A.
Published: August 2010

Abstract. The African oil palm (Elaeis guineensis) is relatively well adapted to the pedoclimatic conditions of central Amazonia. The clayey upland soils of the region are well supplied with nitrogen, although they are deficient in most other nutrients. Under these conditions, oil palm does not respond to N fertilization with yield increases. In this research, the N status of a central Amazonian upland soil was evaluated after having supported a productive oil palm plantation for 15 years without N fertilization. Mineral N in the upper 2 m of soil showed pronounced spatial patterns, with very low concentrations close to the palms, indicative of efficient N uptake by the palms, and evidence for nitrate leaching into the subsoil in the inter‐tree spaces despite the near‐absence of a leguminous cover crop during the previous ten years. The pronounced increases of mineral N with increasing tree distance were explained by increases in N mineralization and a strong decrease in fine root length density of the palms, especially in the subsoil. Failure of the palms to fully occupy the available soil volume with their roots was apparently related to fertilizer placement close to the stem base, which over the years had led to steep fertility gradients between the soil under the trees and the inter‐tree spaces. Broadcast fertilization would have presumably favoured a more extensive lateral root development of the palms, and consequently improved nutrient and water uptake from the inter‐tree spaces. The incomplete soil occupation by the palm roots also suggests that young oil palms can be associated with shade tolerant crops without much risk of root competition. These conclusions may be valid also for other tree crops and may help to reduce nitrate leaching and consequently the need for N fertilization in Amazonian tree crop agriculture.
Progress in studies of nitrate leaching from grassland soils
Authors: Jarvis S.C.
Published: August 2010

Abstract. The large input of research effort on aspects of nitrate leaching over the last two decades has produced many innovative scientific and practical results. The MAFF Nitrate Programme has enabled considerable progress to be made in unravelling much of the complexity of the grassland nitrogen (N) cycle, and identifying gaps as essential first stages in providing improved managements for N in grassland systems. From a practical standpoint, there have been key outputs which have allowed the identification of options for policy, and which should allow grassland farmers to increase the efficiency of N use throughout their farming system and thereby improve the sustainability of their enterprises. As well as quantifying N transformations, transfers and losses, other important outcomes have been the development of user‐friendly models of N cycling (NCYCLE and variants) and an easy to use field kit to determine mineral N in pasture soils. The use of modelling to produce fertilizer recommendations with a Decision Support System and of new approaches developed within the Programme, in particular system synthesis desk studies, and ‘farmlet’ investigations to determine the consequences of modifying N flows and losses, have allowed us to produce solutions to satisfy the dual aims of meeting environmental and economic production targets.
Rice‐soil interactions in Vietnamese acid sulphate soils: impacts of submergence depth on soil solution chemistry and yields
Authors: Tinh Tran Kim , Huong Huynh Thi Thu , Nilsson S. I.
Published: August 2010

Abstract. The aim of this study was to investigate the effects of water submergence depth on radial oxygen loss (ROL), soil solution chemistry and rice growth performance in acid sulphate soils in southern Vietnam. ROL was measured in a solution culture. In a separate pot experiment the impact of water submergence depth on rice growth and soil solution chemistry was studied. Three submergence depths were used in the two experiments (5, 10 and 15 cm). ROL declined with submergence depth and was significantly greater in young roots (with no root hairs) than in older roots. In the pot experiment rice growth and soil solution chemistry were clearly affected by the submergence depth. During the first crop at 5 cm submergence, there was a significantly higher yield and a higher oxidation state (pe+pH) compared to 10 or 15 cm submergence. The Fe concentration was significantly greater at the 5 cm depth compared to the 10 or 15 cm depth. SO42– reduction was delayed at the 5 cm depth. Rice yield was c. 25% less at the 15 cm than at the 5 cm depth. During a second crop, there was a substantial SO42‐ reduction and H2S formation and almost no significant effects of submergence depth on either soil solution chemistry or crop yield. In a field experiment with a dry‐season rice crop, yield and Fe, Al and SO42– concentrations were higher at a shallow submergence depth than at greater depths in the same field, showing similar depth trends to those found during the first crop in the pot experiment. Farmers should be advised to use a shallow submergence depth and, if possible, avoid deep‐rooted rice varieties. A conceptual model is suggested, which summarizes the relationships between ROL and soil solution chemistry.
In situ radiometric mapping of soil erosion and field‐moist bulk density on cultivated fields
Authors: Tyler A.N. , Davidson D.A. , Grieve I.C.
Published: August 2010

Abstract. Recent developments in in situγ ray spectrometry offer a new approach to measuring the activity of radionuclides such as 137Cs and 40K in soils, and thus estimating erosion or deposition rates and field moist bulk density (ρm). Such estimates would be rapid and involve minimal site disturbance, especially important where archaeological remains are present. This paper presents the results of a pilot investigation of an eroded field in Scotland in which a portable hyper pure germanium (HPGe) detector was used to measure γ ray spectra in situ. The gamma (γ) photon flux observed at the soil surface is a function of the 137Cs inventory, its depth distribution characteristics and ρm. A coefficient, QCs, derived from the forward scattering of 137Cs γ ray photons within the soil profile relative to the 137Cs full energy peak (662 keV), was used to correct the in situ calibration for changes in the 137Cs vertical distribution in the ploughed field, a function of tillage, soil accumulation and ρm. Based on only 8 measurements, the agreement between in situγ ray spectrometry and soil sample measurements of 137Cs inventories improved from a non significant r2=0.05 to a significant r2=0.62 (P<0.05). Erosion and deposition rates calculated from the corrected in situ137Cs measurements had a similarly good agreement with those calculated from soil cores. Mean soil bulk density was also calculated using a separate coefficient, QK, derived from the forward scattering γ photons from 40K within the soil relative to the 40K full energy peak (1460 keV). Again there was good agreement with soil core measurements (r2=0.64; P<0.05). The precision of the in situ137Cs measurement was limited by the precision with which QCs can be estimated, a function of the low 137Cs deposition levels associated with the weapons testing fallout and relatively low detector efficiency (35%). In contrast, the precision of the in situ ρm determination was only limited by the spatial variability associated with soil sampling.
Straw management and tillage effects on soil water storage under field conditions
Authors: Jalota S.K. , Khera Romesh , Chahal S.S.
Published: August 2010

Abstract. A two year field study was conducted to evaluate the effects of straw management and tillage on the soil profile (1.5m) water storage, nature of the moisture profile, infiltration and sorptivity as influenced by rainfall, evaporativity (E0) and soil texture. The straw mulch treatment stored more moisture under low E0 rainy conditions in three coarse to medium textured soils. Straw incorporation treatment was better under low E0 rain free conditions, as well as under high E0 rainy conditions in the two coarser textured soils. In the coarsest textured soil, tillage and straw mulching were not effective in maintaining greater soil water storage under high E0 because of the very open nature of the soil. The soil moisture profiles showed a sharper increase in water content below the tilled layer in the tillage and straw‐ incorporation treatments than the untreated and straw mulch treatments. Tillage and straw incorporation treatments increased the sorptivity of the soil compared with untreated and straw mulch treatments respectively. The results of this study suggest that when selecting a suitable soil water conservation practice to increase water storage in the soil profile, information on soil texture and weather (rain and evaporativity) must be considered.
Phosphorus losses from a structured clay soil in relation to tillage practices
Authors: Djodjic F. , Bergström L. , Ulén B.
Published: August 2010

Abstract. Preferential flow may enhance phosphorus transport through the soil profile and thereby increase the risks for eutrophication of watercourses. Destruction of continuous macropores in topsoil by tillage provides the possibility for better contact between soil particles and P fertilizer. This is facilitated by incorporation rather than surface application of fertilizer, which should reduce the risk of rapid P transport from the soil surface through the unsaturated zone. To test this hypothesis, undisturbed soil monoliths (0.295 m in diameter and 1.2 m in length) were collected at a field site with a clay soil in which preferential flow is the dominant solute transport mechanism. After three years of observation, average total P loads reached 1.86, 1.59 and 1.25 kg ha–1for no‐tillage, conventional tillage, and conventional tillage where the P fertilizer was incorporated, respectively. More than 80% of total losses were in the form of dissolved P. The tillage treatment had no significant effect on P leaching loads compared to no‐tillage, but the improved contact between soil particles and P fertilizer resulting from fertilizer incorporation significantly reduced P loads during the first year after application of 100 kg P ha–1. However, after further application of 100 kg P ha–1 two years later, there were no significant differences between the treatments.
Simulating SOC changes in long‐term experiments with RothC and CENTURY: model evaluation for a regional scale application
Authors: Falloon P. , Smith P.
Published: August 2010

Abstract. Predictive, regional use of soil organic matter (SOM) models requires evaluation of the performance of models with datasets from long‐term experiments relevant to the scenarios of interest to the regional scale study, and relevant to the climate of the study region. Datasets from six long‐term experiments were used to evaluate the performance of RothC and CENTURY, two of the most widely used and tested SOM models. Three types of model run were completed for each site: (1) CENTURY model alone; (2) RothC model run to fit measured SOC values, by iteratively adjusting C inputs to soil; and (3) RothC model run using C inputs derived from CENTURY runs. In general, the performance of both models was good across all datasets. The runs using RothC (iteratively changing C inputs to fit measured SOC values) tended to have the best fit to model data, since this method involved direct fitting to observed data. Carbon inputs estimated by RothC were, in general, lower than those estimated by CENTURY, since SOC in CENTURY tends to turn over faster than SOC in RothC. The runs using RothC with CENTURY C inputs tended to have the poorest fit of all, since CENTURY predicted greater C inputs than were required by RothC to maintain the same SOC content. A plausible model fit to measured SOC data may be obtained with widely differing C input values, due to differences in predicted decomposition rates between models. It remains unclear which, if either, modelling approach most closely represents reality since both C inputs to soil and decomposition rates for bulk SOM are difficult to determine experimentally. Further progress in SOM modelling can only be the result of research leading to better process understanding, both of net C inputs to soil and of SOM decomposition rates.  The use of default methods for estimating initial SOC pools in RothC and CENTURY may not always be appropriate and may require adjustment for specific sites. The simulations presented here also suggest details of SOC dynamics not shown by available measured data, especially trends between sampling intervals, and this emphasizes the importance of archived soil samples in long‐term experiments.
The effect of consecutive applications of leaching water applied in equal, increasing or decreasing quantities on soil hydraulic conductivity of a saline sodic soil in the laboratory
Authors: Sahin U. , Anapali O. , Hanay A.
Published: August 2010

Abstract. This study investigated the effect of the same volume of leaching water applied consecutively in either equal amounts or increasing amounts or decreasing amounts on the hydraulic conductivity of a saline sodic soil in 30 cm plastic columns in the laboratory. Gypsum was mixed with the surface 2–3 cm of soil. After leaching, the hydraulic conductivity was measured in each 10 cm depth of soil. Hydraulic conductivity decreased strongly (P<0.05) with depth and the most effective method of applying the water was in gradually increasing amounts.
Agricultural nitrogen balance and water quality in the UK
Authors: Lord E.I. , Anthony S.G. , Goodlass G.
Published: August 2010

Abstract. Nutrient balance calculations have been advocated as indicators of the risk of nitrate loss from agricultural land. To explore this concept, a spatially distributed UK agricultural nitrogen balance was derived using annually updated statistics. The mean UK N surplus for 1995 was 115 kg N ha–1, made up of 51 kg ha–1for arable land, 140 kg ha–1 for agricultural grassland (excluding rough grazing) and an additional 14 kg N ha–1for agricultural land from pig and poultry units. Nitrogen surpluses were greater in lowland grassland (mainly in western, wetter areas) than in arable areas. However nitrate concentrations in rivers were generally greater in arable areas. The relationship between N balance and nitrate leaching was very different for grassland and arable systems, and was also sensitive to climate, level of inputs and management practices. Nitrogen surplus was therefore weakly or even negatively correlated with river nitrate concentrations or loads. A positive correlation was found only where the comparison was restricted to grassland‐dominated catchments. Nitrogen surplus calculations identified areas of very high livestock densities, which would be associated with increased risk of pollution. However their use in isolation as indicators of N leaching, or of progress towards mitigation, could be misleading especially if comparing areas differing in land use, climate or soil type.
Influence of the addition of organic residues on carbohydrate content and structural stability of some highland soils in Ethiopia
Authors: Spaccini R. , Piccolo A. , Mbagwu J.S.C. , Zena Teshale A. , Igwe C.A.
Published: August 2010

Abstract.When over exploited and coupled with climatic conditions, tropical soils are subject to increased erosion and a loss of soil organic matter. Countermeasures include the incorporation of organic materials such as crop and animal residues. We studied the effect of adding crop residues and manure to soil, at five sites in Ethiopia, on carbohydrate properties, aggregate stability and the C and N distribution within water‐stable aggregates. The effects of organic amendments varied between sites. The largest content of carbohydrates was obtained in the control treatment at Holeta, Ginchi (90 kg ha–1mustard meal), Jimma (5 t ha–1cow dung + 9 t ha–1coffee husk), Awassa (forested soil), and Sirinka (soil alley‐cropped withLeuceanae). The aggregate stability of these soils was highly correlated with the OM content but not with carbohydrates. The smaller aggregates (<1.00 mm) accumulated more carbohydrates than the larger (>1.00 mm), thereby suggesting a protecting effect within the finer soil fractions. A protecting role played by humified OM components was also indicated by the C and N distribution as well as the C:N ratios which showed preferential accumulation in small rather than in large aggregates. The isotopic13C‐OC values of carbohydrate extracts were generally low, suggesting that OM was from plants with C3 photosynthetic pathways. Soil treatments with maize alone or combined with coffee husks at Jimma decreased the δ13C‰ values slightly, revealing that maize contributed a share of the labile OM. Despite the improvement in the soil OM content, neither the carbohydrate content nor the aggregate stability were increased to the level of the forested sites, suggesting that the additions of crop residues and manure were not alone sufficient to restore the soil physical quality.
N, P and K budgets for crop rotations on nine organic farms in the UK
Authors: Berry P.M. , Stockdale E.A. , Sylvester‐Bradley R. , Philipps L. , Smith K.A. , Lord E.I. , Watson C.A. , Fortune S.
Published: August 2010

Abstract. Nitrogen (N), phosphorus (P) and potassium (K) budgets were calculated for nine organic farms in the UK. The farms were situated on sandy loams, silty clay loams and silty loams over chalk with stockless farming systems and cattle, pig and poultry enterprises with a significant proportion of arable cropping. A soil surface nutrient budget was calculated for the target rotation on each farm using information about field management and measurements of the soil, crops and manure. Losses of N through leaching and volatilization were calculated independently using the nitcat and manner models. Nutrient budgets for seven of the farm rotations showed an N surplus, six a P surplus and three a K surplus. The ratio of N inputs supplied in the form of biological fixation : manure : atmospheric deposition was approximately 2 : 2 : 1 for stocked systems and 2 : 0 : 1 for stockless systems. Phosphorus surpluses resulted from supplementary P fertilizer (rock phosphate) and additional feed for non‐ruminant livestock. The stockless system without P fertilizer resulted in a large P deficit and stocked systems, which relied on recycling manure alone, a small P deficit. Only rotations with large returns of manure or imported feed showed a K surplus or a balanced K budget.
Effects of organic versus conventional arable farming on soil structure and organic matter dynamics in a marine loam in the Netherlands
Authors: Pulleman M. , Jongmans A. , Marinissen J. , Bouma J.
Published: August 2010

Abstract. We compared the effects of conventional and organic arable farming on soil organic matter (SOM) content, soil structure, aggregate stability and C and N mineralization, which are considered important factors in defining sustainable land management. Within one soil series, three different farming systems were selected, including a conventional and an organic arable system and permanent pasture without tillage. The old pasture represents optimal conditions in terms of soil structure and organic matter inputs and is characterized by high earthworm activity. More than 70 years of different management has caused significant differences in soil properties. SOM content, mineralization, earthworm activity and water‐stable aggregation decreased as a result of tillage and arable cropping when compared with pasture, but were significantly greater under organic farming than under conventional farming. Total SOM contents between 0 and 20 cm depth amounted to 15, 24 and 46 g kg−1 for the conventional arable, organic arable and permanent pasture fields, respectively. Although less sensitive to slaking than the conventionally managed field, the soil under organic farming was susceptible to compaction when high pressures were exerted on the soil under wet conditions. The beneficial effects of organic farming are generally associated with soil biochemical properties, but soil physical aspects should also be considered. Depending on soil type and climate, organic farmers need to be careful not to destroy the soil structure, so that they can enjoy maximum advantage from their organic farming systems.
Influence of estimation procedure on soil organic carbon stock assessment in Flanders, Belgium
Authors: Liebens J. , VanMolle M.
Published: August 2010

Abstract. The purpose of the study was to determine the soil organic carbon (SOC) stock for Flanders, Belgium and to evaluate various methods for assessing SOC stock. The assessment methods first determined the SOC density (C mass per unit area) for pedons in a database of soil properties, and then spatially distributed the SOC density to soil and soil/land use categories on a map. The results showed that the pedon SOC density is influenced by drainage class, texture and land use/land cover. The SOC density estimation method significantly influences results and leads to differences of up to 6% in total estimated SOC stock for Flanders. Use of various spatial distributing methods creates differences of up to 2% in total estimated SOC stock. The largest difference in SOC stock estimate between any combination of assessment methods was 7% (125.6 Tg vs 134.9 Tg). These findings emphasize the importance of complete spatial soil databases of high quality that reduce uncertainty of estimates for use in research examining the role of soils in the C cycle. The results indicate that the need for these databases is greater than the need to standardize methods to determine the spatial distribution of SOC. A map of the distribution of SOC density shows that in Flanders a large proportion of SOC is stored in sandy soils in the north of the territory.
A simple laboratory infiltration method for measuring the tendency of soils to crust
Authors: Mills A.J. , Fey M.V.
Published: August 2010

Abstract.Rainfall simulation experiments give an indication of the tendency of soils to crust or seal but are time‐consuming and require several kilograms of soil per sample. We developed a laboratory infiltration method that is less time‐consuming than rainfall simulation and uses less than 40 g of soil. The method involves the leaching of an agitated 1:5 soil/water suspension through a packed soil column, which simulates the crusting process. The preparation of a dispersed soil suspension is a key feature of the method as it simulates disturbance of a soil surface by rain. This laboratory infiltration method was performed on sandy, granite‐derived soils from annually burnt as well as unburnt plots in the Kruger National Park, South Africa and gave results which correlated strongly with results from rainfall simulation experiments on the same soils. We suggest that this new method may be useful for assessing the effect of different land management practices on the tendency of soils to crust.
Soil organic and inorganic carbon contents of landscape units in Belgium derived using data from 1950 to 1970
Authors: Lettens S. , Van Orshoven J. , van Wesemael B. , Muys B.
Published: August 2010

Abstract. Belgium's soil survey data collected between 1950 and 1970 (pre‐Kyoto Protocol) contain more than 13 000 geo‐referenced soil profile descriptions, which allow the computation of a spatially distributed baseline carbon content for incremental soil depths, based on soil/land‐use combinations (landscape units) and multiple matching soil profile observations. The results show that the soil organic carbon (SOC) and soil inorganic carbon (SIOC) contents of many landscape units do not differ significantly. However, landscape units under forest and grassland tend to contain more carbon. The same is true for landscape units on poorly drained and/or clayey soils, podzols or anthropogenic soils. The change of the SOC in the upper 100 cm of mineral soil follows a logarithmic decline with increasing depth, useful for the extrapolation of SOC of surface layers to deeper layers. SIOC values are strongly related to the geological soil characteristics and increase linearly with depth. Integrating the mean SOC and SIOC content of landscape units over the Belgian territory results in a total soil carbon stock of 303 Mt C in the upper 100 cm layer. Ectorganic horizons contain 35 Mt C and mineral soil contains 245 Mt C in organic form and 23 Mt C in inorganic form. These results are shown to be consistent with an independent set of SOC measurements on 3134 surface samples.
Methane consumption in a frequently nitrogen‐fertilized and limed spruce forest soil after clear‐cutting
Authors: Saari A. , Smolander A. , Martikainen P.J.
Published: August 2010

Abstract. The effects of especially frequent nitrogen (N) additions (from 1959 to 1986, totalling 860 kg N ha−1) and liming (in 1958 and 1980, totalling 6000 kg CaCO3 ha−1) on CH4 uptake by a boreal forest soil were studied in a stand of Norway spruce. Except for a forested reference plot, the stand was clear‐cut in January 1993 and the following year one‐half of each clear‐cut plot was prepared by mounding. Fluxes of CH4 were measured with static chambers in the autumn before clear‐cutting and during the following four summers. The average CH4 uptake during 1993–96 in the forested reference plot was 82 μg CH4 m−2 h−1(ranging from 10 to 147 units). In the first summer after clear‐cutting, the cleared plot showed 42% lower CH4 uptake rate than the forested reference plot, but thereafter the difference became less pronounced. The short‐term decrease in CH4 consumption after clear‐cutting was associated with increases in soil NH4+ and NO3−concentrations. Mounding tended at first to stimulate CH4 uptake but later to inhibit it. Neither liming nor N‐fertilization had significant effects on CH4 consumption. Our results suggest that over the long term, in N‐limited upland boreal forest soils, N addition does not decrease CH4 uptake by the soil.
Re‐defining tillage erosion: quantifying intensity–direction relationships for complex terrain
Authors: Quine T.A. , Zhang Y.
Published: August 2010

Abstract. Current tillage erosion models account for the influence of tillage direction in the magnitude of the soil (tillage) transport coefficient. It is argued here that this is counter‐intuitive and causes significant problems in modelling tillage erosion in areas of complex terrain. This article examines whether a re‐modelling of tillage erosion is possible that separates tillage direction (an interaction with the landform) from the soil transport coefficient (a measure of tillage intensity representing the combination of implement erosivity and soil erodibility). Experimental data for mouldboard ploughing upslope, downslope and cross‐slope at Coombe Barton Farm, Devon are examined. Integration of data for all directions into a single relationship, which relates translocation in the direction of tillage to slope in the direction of tillage and translocation perpendicular to tillage to slope perpendicular to tillage, is not possible using previously published methods of analysis. However, when total translocation distance is regressed against the tangent of the slope at 45° to the tillage direction (bisecting the tillage direction and the direction of overturning) it is found that a single relationship can be used to describe tillage in all three directions. Therefore, this relationship is used to determine a single value of the soil transport coefficient (kfTa) for constant soil and implement conditions but different tillage directions. This redefinition of tillage is important both for true estimation of tillage erosion severity, the adirectional coefficient being 40% larger than the directional coefficient, and for modelling of tillage erosion in complex terrain. These improvements are vital when tillage erosion simulation is used to direct soil conservation strategies.
Mitigation of greenhouse gas emissions from soil under silage production by use of organic manures or slow‐release fertilizer
Authors: Ball B.C. , McTaggart I.P. , Scott A.
Published: August 2010

Abstract. Grassland is a major source of nitrous oxide (N2O) and methane (CH4) emissions in the UK, resulting from high rates of fertilizer application. We studied the effects of substituting mineral fertilizer by organic manures and a slow‐release fertilizer in silage grass production on greenhouse gas emissions and soil mineral N content in a three‐year field experiment. The organic manures investigated were sewage sludge pellets and composted sewage sludge (dry materials), and digested sewage sludge and cattle slurry (liquid materials). The organic manures produced N2O and carbon dioxide (CO2) consistently from time of application up to harvest. However, they mitigated N2O emissions by around 90% when aggregate emissions of 15.7 kg N ha−1 from NPK fertilizer were caused by a flux of up to 4.9 kg N ha−1 d−1 during the first 4 days after heavy rainfall subsequent to the NPK fertilizer application. CH4 was emitted only for 2 or 3 days after application of the liquid manures. CH4 and CO2 fluxes were not significantly mitigated. Composting and dried pellets were useful methods of conserving nutrients in organic wastes, enabling slow and sustained release of nitrogen. NPK slow‐release fertilizer also maintained grass yields and was the most effective substitute for the conventional NPK fertilizer for mitigation of N2O fluxes.
Organic carbon stocks in the soils of Brazil
Authors: Batjes N.H.
Published: August 2010

Abstract. Soil organic carbon stocks to 1 m for Brazil, calculated using an updated Soil and Terrain (SOTER) database and simulation of phenoforms, are 65.9–67.5 Pg C, of which 65% is in the Amazonian region of Brazil. Other researchers have obtained similar gross results, despite very different spatial patterns mapped due to use of different methods.
3, 4‐Dimethylpyrazole phosphate reduces nitrous oxide emissions from grassland after slurry application
Authors: Merino P. , Menéndez S. , Pinto M. , González‐Murua C. , Estavillo J.M.
Published: August 2010

Abstract. A field study was conducted to assess the effect of the nitrification inhibitor 3,4‐dimethylpyrazole phosphate (DMPP), applied at a rate of 1 kg ha−1, on nitrous oxide (N2O) emissions, forage production and N extraction from a grassland soil after cattle slurry applications in autumn and spring. Nitrous oxide emissions were measured daily or weekly using the closed chamber technique. DMPP efficiency after slurry application was lower in spring (16.7 °C mean soil temperature) than in autumn (11.4 °C mean soil temperature). Thus, DMPP was able to maintain soil mineral N in the ammonium form for 22 days and reduce cumulative N2O emissions by 69% in autumn, while in spring its effect on soil mineral N lasted for 7–14 days, reducing cumulative N2O losses by 48%. Furthermore, application of DMPP after slurry did not decrease biomass yield or N uptake.
Estimation of net N mineralization from short‐term C evolution in a plant residue‐amended soil: is the accuracy of estimation time‐dependent?
Authors: Vahdat E. , Nourbakhsh F. , Basiri M.
Published: August 2010

Estimating N mineralization is important both environmentally and economically. Chemical and biological tests have been used for many years in an attempt to predict the N‐supplying capacity of soil. Simple methods are needed to predict N mineralization as a means to guide N management in rangeland ecosystems dependent on the natural N‐supplying capacity of soils. A short‐term C mineralization assay may provide a routine and rapid procedure to attain this goal. The objective of this study was to investigate the association of C and N mineralization in a calcareous soil. A calcareous soil was amended with eight range plant materials and incubated under aerobic condition (50% water holding capacity) at 25 °C. The potentially mineralizable C (C0) values ranged from 2232 mg C/kg soil with a decomposition rate constant (k) of 0.058/day forHordeum bulbosumL. to 2834.2 mg C/kg soil with a k value of 0.115/day forMedicago sativaL. treatment. The k value forMedicago sativaL. treatment (0.115/day) was about two times greater than that ofHordeum bulbosumL. (0.058/day). The product of k and C0(kC0) was highly correlated (r = 0.96,P < 0.001) with N mineralization/immobilisation (Nm). Moreover, Nmwas more strongly correlated (r = 0.95,P < 0.001) with cumulative CO2‐C evolved during the first 6 days of incubation than other incubation periods. Overall, the quantities of Nmwere closely associated with kC0and short‐term CO2‐C evolution. The degree of association between C and N mineralization is time‐dependent.
Medicare Payments for Common Inpatient Procedures: Implications for Episode‐Based Payment Bundling
Authors: Birkmeyer John D. , Gust Cathryn , Baser Onur , Dimick Justin B. , Sutherland Jason M. , Skinner Jonathan S.
Published: August 2010

Background. Aiming to align provider incentives toward improving quality and efficiency, the Center for Medicare and Medicaid Services is considering broader bundling of hospital and physician payments around episodes of inpatient surgery. Decisions about bundled payments would benefit from better information about how payments are currently distributed among providers of different perioperative services and how payments vary across hospitals.

Study Design. Using the national Medicare database, we identified patients undergoing one of four inpatient procedures in 2005 (coronary artery bypass [CABG], hip fracture repair, back surgery, and colectomy). For each procedure, price‐standardized Medicare payments from the date of admission for the index procedure to 30 days postdischarge were assessed and categorized by payment type (hospital, physician, and postacute care) and subtype.

Results. Average total payments for inpatient surgery episodes varied from U.S.$26,515 for back surgery to U.S.$45,358 for CABG. Hospital payments accounted for the largest share of total payments (60–80 percent, depending on procedure), followed by physician payments (13–19 percent) and postacute care (7–27 percent). Overall episode payments for hospitals in the lowest and highest payment quartiles differed by U.S.$16,668 for CABG, U.S.$18,762 for back surgery, U.S.$10,615 for hip fracture repair, and U.S.$12,988 for colectomy. Payments to hospitals accounted for the largest share of variation in payments. Among specific types of payments, those associated with 30‐day readmissions and postacute care varied most substantially across hospitals.

Conclusions. Fully bundled payments for inpatient surgical episodes would need to be dispersed among many different types of providers. Hospital payments—both overall and for specific services—vary considerably and might be reduced by incentives for hospitals and physicians to improve quality and efficiency.
A new preclinical biomarker for risk of Torsades de Pointes: drug‐induced reduction of the cardiac electromechanical window
Authors: Vargas Hugo M
Published: August 2010

Evaluation of new therapeutic agents for their potential to cause QT interval prolongation and drug‐induced ventricular arrhythmia, like Torsades de Pointes (TdP), is a critical activity during drug development. The QT interval has been used as a surrogate biomarker to assess ventricular repolarization effects caused by drug‐induced blockade of cardiac repolarizing currents, mainly IKr, but is imperfect in predicting proarrhythmia. Evidence suggests that left ventricular mechanical dysfunction may also contribute to ventricular arrhythmias; thus, electrical and mechanical alterations may have a role in drug‐induced TdP. The electromechanical window (EMw) represents the time difference between the end of electrical systole (i.e. the QT interval) and the completion of ventricular relaxation (i.e. the QLVPend interval), and appears to be a new potential biomarker for TdP risk. A reduction in the EMw (to negative values) has now been shown to be associated with the onset of TdP in an anaesthetized dog model of long QT1 syndrome. Therefore, the EMw represents a novel indicator of TdP risk that may add predictive value beyond assay of drug‐induced QT interval prolongation.

LINKED ARTICLE This article is a commentary on van der Linde et al., pp. 1444–1454 of this issue. To view this paper visit http://dx.doi.org/10.1111/j.1476‐5381.2010.00934.x
Effect of experimental hyperlipidaemia on the electrocardiographic effects of repeated doses of halofantrine in rats
Authors: Patel Jigar P , Brocks Dion R
Published: August 2010

BACKGROUND AND PURPOSEHalofantrine can cause a prolongation of the cardiac QT interval, leading to serious ventricular arrhythmias. Hyperlipidaemia elevates plasma concentration of halofantrine and may influence its tissue uptake. The present study examined the effect of experimental hyperlipidaemia on QT interval prolongation induced by halofantrine in rats.

EXPERIMENTAL APPROACHNormolipidaemic and hyperlipidaemic rats (induced with poloxamer 407) were given 4 doses of halofantrine (i.v., 4–40 mg·kg−1·d−1) or vehicle every 12 h. Under brief anaesthesia, ECGs were recorded before administration of the vehicle or drug and 12 h after the first and last doses. Blood samples were taken at the same time after the first and last dose of halofantrine. Hearts were also collected 12 h after the last dose. Plasma and heart samples were assayed for drug and desbutylhalofantrine using a stereospecific method.

KEY RESULTSIn the vehicle group, hyperlipidaemia by itself did not affect the ECG. Compared to baseline, QT intervals were significantly higher in both normolipidaemic and hyperlipidaemic rats after halofantrine. In hyperlipidaemic rats, plasma but not heart concentrations of the halofantrine enantiomers were significantly higher compared to those in normolipidaemic rats. Despite the lack of difference in the concentrations of halofantrine in heart, QT intervals were significantly higher in hyperlipidaemic compared to those in normolipidaemic rats.

CONCLUSIONS AND IMPLICATIONSThe unbound fraction of halofantrine appeared to be the controlling factor for drug uptake by the heart. Our data suggested a greater vulnerability to halofantrine‐induced QT interval prolongation in the hyperlipidaemic state.
Thinking Historically about Medieval Emotions
Authors: Rosenwein Barbara H.
Published: August 2010

The recent focus on emotions in history raises numerous methodological questions. How are historians to approach texts that include emotions? This essay summarizes three dominant interpretative paradigms for interpreting medieval emotions. In the first, these emotions are seen as the uninhibited release of affect. In the second, they are viewed as well‐understood modes of communication in a society that used gesture as often as it used words. In the third, they are understood as norms within an emotional community. Arguing that the latter two interpretations are fruitful, the author concludes by suggesting some methodological tools to help historians more rigorously assess and work with the emotions in the texts of the past.
An Orientation to the Sources and Study of Early Islamic Egypt (641–868ce)
Authors: Mikhail Maged S. A.
Published: August 2010

This article surveys the most important Christian (Coptic and Melkite) and Islamic sources for the study of Egypt from the Arab conquest (641ce) through the mid‐ninth century. Beginning with a discussion of reference works, the article turns to narrative, hagiographic, and apocalyptic texts that focus specifically on Egypt. The latter section identifies the essential print and online resources for the study of Greek, Coptic, and Arabic papyri through the ninth century.