ALBERT

Notizen: At first one is very pleased at being invited to write a Prefatory Chapter, but as the delivery deadline draws closer one begins to think, "Oh my God! What on earth can I say that all but family members and few close friends will not find a great bore?" One solution is to write a scientific essay, but I concluded that that was a cop-out. I decided that perhaps the best tack to follow was to try to convey to the reader the personal characteristics I bring to my science and to other aspects of my professional career. The writing of this chapter has certainly convinced me that my particular background influenced what problems I chose to work on and how I approached their solution, but I hope that my results have a more ecumenical significance. There's been much written recently about how one's cultural background affects one's science, but I think that thesis can also be exaggerated. Science is a method of inquiry that by using certain guidelines permits rational individuals to observe Nature in a way that their findings will agree and have permanence. We shouldn't be diffident about defending that claim of objectivity.

Notizen: Abstract CD40-CD154-mediated contact-dependent signals between B and T cells are required for the generation of thymus dependent (TD) humoral immune responses. CD40-CD154 interactions are however also important in many other cell systems. CD40 is expressed by a large variety of cell types other than B cells, and these include dendritic cells, follicular dendritic cells, monocytes, macrophages, mast cells, fibroblasts, and endothelial cells. CD40- and CD154-knockout mice and antibodies to CD40 and CD154 have helped to elucidate the role of the CD40-CD154 system in immune responses. Recently published studies indicate that CD40-CD154 interactions can influence T cell priming and T cell-mediated effector functions; they can also upregulate costimulatory molecules and activate macrophages, NK cells, and endothelia as well as participate in organ-specific autoimmune disease, graft rejection, and even atherosclerosis. This review focuses on the role of the CD40-CD154 system in the regulation of many newly discovered functions important in inflammation and cell-mediated immunity.

Notizen: Abstract Immunological memory can be defined as the faster and stronger response of an animal that follows reexposure to the same antigen. By this definition, it is an operational property of the whole animal or the immune system. Memory cells express a different pattern of cell surface markers, and they respond in several ways that are functionally different from those of naive cells. Murine memory cells are CD44 high and low in the expression of activation markers such as CD25 (IL-2R), whereas human memory cells are CD45RA-, CD45RO+. In contrast to naive cells, memory cells secrete a full range of T cell cytokines and can be polarized to secrete particular restricted patterns of secretion for both CD4 and CD8 T cells. The requirements for the activation of memory cells for proliferation and cytokine production are not quite as strict as those of naive cells, but costimulation in the broad sense is required for optimum responses and for responses to suboptimum antigen concentrations. It would appear that memory cells can persist in the absence of antigenic stimulation and persist as nondividing cells. Reencounter with the same antigen can expand the population to a new, stable, higher level and generate a separate population of CD44 high effectors that may be required for protection, while competition from other antigens can drive it down to a lower stable level. It is unclear how or where memory cells arise, but once generated they have different pathways of recirculation and homing.

Notizen: Abstract NK cells are regulated by opposing signals from receptors that activate and inhibit effector function. While positive stimulation may be initiated by an array of co-stimulatory receptors, specificity is provided by inhibitory signals transduced by receptors for MHC class I. Three distinct receptor families, Ly49, CD94/NKG2, and KIR, are involved in NK cell recognition of polymorphic MHC class I molecules. A common pathway of inhibitory signaling is provided by ITIM sequences in the cytoplasmic domains of these otherwise structurally diverse receptors. Upon ligand binding and activation, the inhibitory NK cell receptors become tyrosine phosphorylated and recruit tyrosine phosphatases, SHP-1 and possibly SHP-2, resulting in inhibition of NK cell-mediated cytotoxicity and cytokine expression. Recent studies suggest these inhibitory NK cell receptors are members of a larger superfamily containing ITIM sequences, the inhibitory receptor superfamily (IRS).

Notizen: Abstract This review summarizes the clinical history and rationale for xenotransplantation; recent progress in understanding the physiologic, immunologic, and infectious obstacles to the procedure's success; and some of the strategies being pursued to overcome these obstacles. The problems of xenotransplantation are complex, and a combination of approaches is required. The earliest and most striking immunologic obstacle, that of hyperacute rejection, appears to be the closest to being solved. This phenomenon depends on the binding of natural antibody to the vascular endothelium, fixation of complement by that antibody, and finally, activation of the endothelium and initiation of coagulation. Therefore, these three pathways have been targeted as sites for intervention in the process. The mechanisms responsible for the next immunologic barrier, that of delayed xenograft/acute vascular rejection, remain to be fully elucidated. They probably also involve multiple pathways, including antibody and/or immune cell binding and endothelial cell activation. The final immunologic barrier, that of the cellular immune response, involves mechanisms that are similar to those involved in allograft rejection. However, the strength of the cellular immune response to xenografts is so great that it is unlikely to be controlled by the types of nonspecific immunosuppression used routinely to prevent allograft rejection. For this reason, it may be essential to induce specific immunologic unresponsiveness to at least some of the most antigenic xenogeneic molecules.

Notizen: Abstract Covalent attachment of activated complement C3 (C3d) to antigen links innate and adaptive immunity by targeting antigen to follicular dendritic cells (FDC) and B cells via specific receptors CD21 and CD35. Recent characterization of knockout mice deficient in complement components C3, C4, or the receptors CD21 and CD35 as well as biochemical studies of the CD21/CD19/Tapa-1 coreceptor on B cells have helped to elucidate the mechanism of complement regulation of both B-1 and B-2 lymphocytes. Interestingly, natural antibody of the adaptive immune system provides a major recognition role in activation of the complement system, which in turn enhances activation of antigen-specific B cells. Enhancement of the primary and secondary immune response to T-dependent antigens is mediated by coligation of the coreceptor and the B cell antigen receptor, which dramatically increases follicular retention and B cell survival within the germinal center. Most recent evidence suggests that complement also regulates elimination of self-reactive B cells, as breeding of mice that are deficient in C4 or CD21/CD35 with the lupus-prone strain of lpr mice demonstrates an exacerbation of disease due to an increase in autoantibodies.

Notizen: Several recent studies have challenged the conventional notion that raising the minimum wage has negative labor market consequences. In particular, most recent minimum wage research has considered teen employment, with virtually no examination of unemployment rates. Given the conflicting findings in the recent literature, this study reconsiders this issue by examining the minimum wage's influence on teen unemployment rates. The empirical analysis considers state data from the latter 1980s, a unique period where many states raised their minimum wage above the federal level. The results suggest that both a greater minimum wage rate and greater minimum wage coverage increase teen unemployment rates. Further evidence suggests that employment declines outweigh teen labor force reductions, suggesting that increases in unemployment are primarily caused by labor demand shifts. Thus, policy makers should weigh these costs in deciding future minimum wage hikes.

Notizen: The purpose of this study is to analyze the effects of transportation investment on the Korean economy using the dynamic Computable General Equilibrium model. The result of the counterfactual analysis shows that infrastructure investment policy has the advantage of economic growth, but the disadvantage of price inflation. The elasticities of infrastructure investment with respect to GDP, export, private utility, and inflation depend on institutional restrictions on the domestic inflow of foreign capital and financing alternatives for infrastructure projects. The growth effect of transportation investment would be maximized if regulations on inflow of foreign capital to the private sector were lifted. On the other hand, the effect of transportation investment on inflation would be minimized if transportation investment expenditure were completely financed by tax revenues.

Notizen: Many states are striving to meet public demand for accountability by “benchmarking”—setting social goals for the state and tracking progress in meeting the goals. However, states are finding it difficult to set realistic targets and to assess the impacts of policy on achievement of the targets without a framework that models the relationships among policy targets, policy actions and social and economic forces outside the control of policymakers. This paper develops a dynamic simulation model of one “benchmark” (poverty incidence) in Oregon, linking transitions into and out of poverty to various events (increased earnings, or having a child as a teenager, for example), and linking these events to policy. The simulation results suggest that, with current policies, Oregon will come close to achieving its poverty benchmark target of 11 percent by the year 2000 if economic conditions remain favorable. The model is used to examine the impact on poverty incidence of three policy strategies: reducing high school dropout and teen pregnancy rates, increasing the effectiveness of social support programs to JOBS participants, and boosting job growth. The simulation results suggest that when assessing the state's performance or “grading” the observed trend in the poverty benchmark, policymakers should take into account the performance of the state (and national) economy. The impact of policy efforts to reduce poverty is limited because many poverty spells are caused largely by events not affected by current state policies.

Notizen: Previously it was reported that regional variations in well-being (poverty, per capita income, and family income) among Appalachian counties did not originate from regional variations in urbanization, but from regional differences in well-being among nonmetropolitan counties. It was argued that southern Appalachian counties had higher levels of well-being at the end of the 1980s because nonmetropolian counties in southern Appalachia experienced greater economic growth during the 1980s than did nonmetropolitan counties in other Appalachian regions. In this paper these data are reanalyzed to test to what extent the original findings are affected by the presence (and failure to control) spatial autocorrelation. Using a spatial lag model it is shown that correcting for spatial autocorrelation statistically altered the original results. However, substantively, the conclusions from the original analysis did not change: regional differences in county well-being in Appalachia are largely the product of regional differences among nonmetropolitan counties, even after correcting the model for spatial autocorrelation.

Notizen: Over the last twenty-five years local governments in the United States and Canada have increasingly used impact fees and other development exactions as methods of financing capital and infrastructure requirements mandated by residential growth. While several studies have examined the effects of impact fees on housing and land prices, rigorous empirical analysis of their effects on residential development is lacking. In this paper a sample of all municipalities in DuPage County, Illinois from 1977 through 1992 is used to examine the effects of impact fees on the rate of residential development. The empirical results show that impact fees reduce rates of residential development by more than 25 percent.

Notizen: Within the last decade, a considerable literature has emerged on the growth and location of producer services employment in North America, and in the role of labor market characteristics in shaping these changes. One of the outcomes of this research has been the realization that producer services are overwhelmingly concentrated in metropolitan areas, and that there is a strong core-periphery dichotomy in the representation of these activities. This paper explores the labor market characteristics of a set of producer service activities within the peripheral urban hierarchy of Saskatchewan, Canada, dominated by the regional cores of Saskatoon and Regina, and surrounded by ten peripheral regions. The data set was provided by Employment Canada, and divided into Canada Employment Centre (CEC) Areas. It was found that the higher order producer services, such as Finance and Business Services, are significantly underrepresented relative to the rest of Canada, while others, such as Services to Primary Producers and Transportation and Communications, are significantly overrepresented. However, the nature of these services, as reflected in their labor market characteristics, are very different. Gender and the role of part-time labor appear to be distinguished on the basis of the specific producer service sector, with very few distinctions across space. On the other hand, differences in the roles played by part-year labor is less related to the sector and more related to position within the peripheral hierarchy. Although the heartland-hinterland model is usually applied at national or even international scales of analysis, the nature of the segmentation of the producer services labor force, and its relationship to urbanization and development of the sector, imply that the model can in fact be used as a fiamework for analyzing intraregional employment relationships within the periphery. This study highlights the nature of the labor force as one aspect of this framework.

Notizen: Book review in this article:The Death of Distance: How the Commltnications Revolution Will Change Our Lives. By Frances Cairncross.The Dynamics of Industrial Location: the Factory, the Firm and the Production System. By Roger Hayter.The Japanese City. Edited by P.P. Karan and Kristin Stapleton.Globalization and Neoliberalism: the Caribbean Context. edited by Thomas Klak.Regions And The World Economy: The Coming Shape Of Global Production, Competition And Political Order. By Allen J. Scott.

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

Notizen: Abstract. Phosphorus budgets have been compiled for two contrasting grassland farming systems in the UK; intensive dairy farming and extensive hill sheep production. Balance sheets of inputs, recycling of P through the soil–plant–animal pathway and outputs are presented to determine the potential rate of P accumulation in the two systems. A typical 57 ha intensive dairy farm with 129 lactating cows imports 2.48t P via fertilizer, bedding and concentrates, plus a small amount from the atmosphere, of which 0.98t are exported in milk, calves and transfer from soil to the aquatic environment. Therefore 1.5t of P are retained within the farm each year, which equates to an accumulation rate of 26 kg/ha in the plant-soil system. This surplus occurs despite a fertilizer input of only 16 kg/ha. However, a large proportion of P, equivalent to 27 kg/ha, is imported in feed concentrates.For the typical 841 ha hill sheep farm supporting 694 Blackface ewes, P inputs and outputs are 0.66 and 0.42 t/yr, respectively. Therefore, approximately 0.24t P are retained within the farm, which is equivalent to an accumulation rate of 0.28 kg/ha per yr. In comparison to the small annual inputs and outputs of P on the hill farm, much P, 2.48t, is recycled through the plant-soil and plant-animal-soil pathways on the hill sheep farm. For both farming systems there is a net input of P, although the rate of accumulation is ten times greater for the dairy farm where the annual retention of P represents 60% of the total P inputs, compared with 36% on the hill sheep farm.

Notizen: Abstract. Scientific land and soil resource surveys have had only limited impacts locally on development and extension practice in the tropics. They are thought to have little relevance for subsistence farmers. Their failure to accommodate local social and cultural priorities is a factor. Soil scientists have, until recently, given little attention to others’ understanding of soil or ‘ethnopedology’. The incorporation of indigenous soil and land resource knowledge has recently been advocated to improve their relevance. But a common error is uncritically to impose a western scientific model, which may distort understanding. The ill-informed, decontextualised knowledge that results may even promote negative interventions. This paper criticises the narrow idea of ‘indigenous technical knowledge’, citing evidence from Papua New Guinea, Bangladesh and Indonesia. While we find farmers consistently use some of the same information as scientists to assess soils, their definitions of soils and land types are often at odds. Scientists identify classes by a range of technically assessed properties, whereas farmers may not. Their more holistic approach also accounts in part for the disjunction, frequently incorporating exotic social and cultural aspects. The wider use of indigenous soil notions in agrotechnology transfer may be limited too by some of their intrinsic characteristics, inclined to be location specific, and culturally relative.

Notizen: Abstract. Two field trials were established in 1991 to determine the effects on crop yield, N uptake, soil moisture content and heavy metal concentration of applying de-inked paper mill sludge (DPMS) over the period 1991 to 1993. In the first year, during decomposition of the DPMS, N immobilization occurred resulting in loss of cereal yield (P 〈 0.05) at low rates of N fertilizer. Approximately 40 kg extra N fertilizer/ha was required per 100t DPMS/ha to compensate for this N immobilization. Soil volumetric moisture content was increased (P 〈 0.001) by c. 20% at both sites by 200 and 300t DPMS/ha. DPMS did not significantly increase (P 〉 0.05) soil concentrations of total Zn, Cu and Pb. Soil nitrate concentrations after harvest were reduced (P 〈 0.01) by c. 17 mg N/kg per 100t DPMS/ha with increasing rates of DPMS up to 200 t/ha. In the second year following the DPMS application, there were no significant effects on grain yield indicating that very little or no N was immobilized. By the third year, the soil N supply was 7 kg N/ha higher where a single dressing of 100t DPMS/ha had been applied compared to the control. This resulted in an overall yield increase of 7% (P 〈 0.10). Soil N supply was lower (N.S.) but crop yields were similar (P 〉 0.05) to the control where single dressings of 200 and 300t DPMS/ha had been applied.

Notizen: Abstract. Nitrate leaching and pasture (Lolium perenne / Trifolium repens) yields were measured on monolith lysimeters (80 cm diam. × 120 cm depth) of a Templeton sandy loam soil (Udic Ustochrept), following repeated applications of dairy shed effluent (DSE) or ammonium fertilizer (NH4Cl), under spray (50 mm/month) or flood (100 mm/month) irrigation. Applications of DSE at 400 kg N/ha per annum resulted in significantly less nitrate leaching (8–25 kg N/ha per yr) compared with NH4Cl (28–48kg N/ha per yr) (P 〈 0.01). Over the two year period, the total mineral N (predominantly nitrate) leached was equivalent to 2.5–3.7% of the total N applied in the DSE and 8.7–9.8% of the N applied in the NH4Cl. There was a trend of slightly less nitrate leaching under the flood irrigation than under the spray irrigation, probably because of the greater potential for denitrification under the wetter conditions. Average nitrate concentrations in the leachate were generally below the drinking water standard except in the NH4Cl treatment under spray irrigation where it averaged 10 mg NO3-N/l over the two year period. DSE was equally as effective as NH4Cl in stimulating pasture dry matter production. Annual nitrogen uptakes were similar for the DSE (343 kg N/ha) and NH4Cl (332–344kg N/ha) treatments in the first year but were higher in the DSE (361–412 kg N/ha) than in the NH4Cl (324–340 kg N/ha) treatments in the second year. Pasture uptakes of phosphorus and sulphur were also higher in the DSE than in the NH4Cl treatments in the second year. The results emphasize the need to set different regulatory limits for land application of organic wastes of various types and for N fertilizers.

Notizen: Abstract. Organic indices and aggregate stability were measured in soils of similar texture on two restored opencast coal sites and on adjacent, undisturbed land in South Wales, UK. The aim was to assess rates of soil change over time, to relate these changes to conditions in undisturbed land and to evaluate organic-aggregation relationships across these range of soils. Several management factors were included in the comparisons.Organic matter accumulated at the surface (0–7.5 cm) of restored soils, contents being greater than undisturbed soils after 21 years. However, this increase in total organic matter did not result in proportionate increases in carbohydrates and microbial biomass, nor did aggregate stability increase to the degree expected. Between 7.5 and 15 cm depth, rates of change were slower. Microbial metabolic quotient and respiration relative to total soil C were highest in recently (9 years) restored soils, intermediate in 21 year old restored soils and least for undisturbed soils.Sewage (100t/ha) applied at reinstatement improved clay stability but had little effect on other parameters when measured 9 years later. Drainage of soils restored in 1972 reduced total organic content but its influence on other organic indices was more complex. Carbohydrate contents had the closest association with aggregate stability and microbial biomass.Although the productivity of restored land may recover more quickly, findings suggest that rehabilitation of normal soil processes following surface mining may take much longer than the normal five year aftercare period.

Notizen: Abstract. Recently, there has been interest in the occurrence of bromide (Br-) in natural waters since it has been demonstrated that Br-, in association with humic substances in raw waters, is readily incorporated into haloacetic acids in the form of organically bound bromine (Br) during water chlorination. We report results of the effects of experimentally rewetting a naturally drained gully mire on the hydrochemistry of Br-, iron (Fe) and dissolved organic carbon (DOC) in the peat water. Results obtained over a three year period showed that rewetting substantially increased the concentrations of these solutes in the pore water, with peak values of 1 mg dm-3 (Br-), 〉 60 mg dm-3 (Fe) and 〉 300 mg dm-3 (DOC) detected in some samples after rewetting, compared with typical values 〈 0.05 mg dm-3 (Br-), 〈 1 mg dm-3 (Fe) and 〈 15 mg dm-3 (DOC) under the drained conditions. Bromide, Fe and DOC release were highly seasonal, with the largest concentrations observed in late-summer to autumn. However, whereas seasonal peak concentrations of Fe and DOC have since remained at these higher levels, seasonal peak concentrations of Br- were progressively attenuated over time, suggesting the latter phenomenon is a flush effect, with no longer-term consequences for water quality.

Notizen: 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-1 total 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.

Notizen: Book reviewed in this articles: Land Restoration and Reclamation: Principles and Practice. By J.A. Harris, P. Birch & J.P. Palmer.

Notizen: Abstract. Nitrate leaching under newly planted Miscanthus grass was measured for three years. The crop received either no fertilizer-N or an annual spring application of 60 kg or 120 kg N ha-1. During three winters soil water was collected from porous cup probes installed 90 cm deep. Nitrate leaching was calculated from the mean drain flow recorded in two drain gauges multiplied by the mean nitrate-N concentration in the soil water solutions collected. In the first year soil water nitrate concentrations were high on all treatments and N losses were 154, 187 and 228 kg ha-1 respectively on the unfertilized treatment and those that received 60 or 120 kg N ha-1. Leaching losses in the second and third years were, in turn, 8, 24 and 87 kg ha-1 and 3, 11 and 30 kg ha-1 for the unfertilized treatment and for the 60 and 120 kg N ha-1 treatments respectively. Leaching losses were closer to those recorded under extensively managed grassland than arable land. The large losses in the first year were probably due to the previous agricultural management at the site and excessive inputs of N on the fertilized plots. In the second and third year, lower drainage volumes may also have influenced losses. The results show that Miscanthus, once established, can lead to low levels of nitrate leaching and improved groundwater quality compared with growing arable crops.

Notizen: Abstract. The SOILN model with a crop growth submodel for grass and cereal crops and the associated soil water and heat model SOIL were selected out of a number of similar models to simulate nitrogen cycling in a soil/crop system. The main parameter values required by the model were selected on the basis of a combination of field experiments and literature sources. Experimental data measured on grassland at Dumfries in the West of Scotland and on arable land at Bush Estate near Edinburgh were used to test the model. Simulated biomass yields and nitrogen contents of harvested biomass were in reasonable agreement with measured values for both grass and cereal crops. There were similar trends in accumulated leached nitrate between the simulations and experiments at the sites. Any discrepancy between simulated and measured nitrate leached appeared to correspond to similar discrepancies between simulated and measured water flow. The comparison between simulated and experimental results suggests that the model with the selected parameter values can simulate nitrogen and carbon cycling both in grassland and in arable land, and make convincing predictions about the effects of varying soil, crop, fertilizer and manure management practices. A basic sensitivity analysis carried out on the parameters determining the biological and biochemical processes showed the model predictions of annual N-leaching are relatively insensitive to all but two of the plant parameters. However, the model predictions of annual N-harvested and dry mass production are sensitive to numerous plant parameters.

Notizen: Abstract. Nitrogen (N) is of enviromental concern if it leaches or is released as nitrous oxide (N2O,). In order to utilize N efficiently in grazed pasture systems, the fluxes of N from various sources need to be quantified. One flux is N mineralization from organic sources. Previous work has examined incubation and chemical extraction of soils as methods to determine N mineralization potential. This paper re-examines new and previously published data on net mineralization, with the aim of examining the relationships between soil thermal units, net N mineralization (measured using acetylene incubations) and dry matter production in pastures. Net N mineralization is expressed as N turnover (net N mineralization as a % of total soil N). Relationships are developed between soil thermal units, dry matter production, and N turnover. These relationships have potential in advising farmers on potential N mineralization from soil organic matter. A second use of such relationships is the modelling of N transformations in pasture systems. Further work should explore the effect of soil moisture on such relationships and examine the relationship between soil thermal units and uptake of N by pasture.

Notizen: Abstract. The effect of nitrogen fertilizer inputs to cereal crops on nitrate leaching after harvest was tested on 21 experiments on sandy soils in England. At small nitrogen fertilizer rates leaching increased very little with increasing inputs, while at high rates more than half of any additional nitrogen could be accounted for as increase in nitrate leached. In many cases the response fitted two straight lines. Nitrogen offtake in grain also fitted two straight lines, with a form which complemented the leaching response. The gradient averaged 0.52 kg N in grain for every additional 1kg N applied below the break point, but only 0.05 kg/kg above. The break points were generally close to or above the economic optimum N input. The effect of inputs on leaching could he quantitatively related to nitrogen offtake in grain, assuming a constant ratio of nitrogen in grain to total nitrogen uptake. The results show that fields receiving N inputs in excess of the economic optimum cause a disproportionately large nitrate loss. However because of uncertainty in predicting the break point in advance, modest further reduction in leaching will occur by reducing inputs to somewhat below the expected economic optimum.

Notizen: Book Reviewed in this article:Land resources: on the edge of the Malthusian precipice? Edited by D. J. Greenland, P. J. Gregory & P. H. Nye

Notizen: Abstract. The effects on nitrate leaching of incorporation of paper mill waste at three cultivation depths in fields previously cropped to iceberg lettuce and calabrese are reported. In the lettuce experiment, incorporation of 40 t DM paper mill waste/ha resulted in a decrease in N leaching (measured with suction cups) from 177 to 94 kg/ha (S.E.d= 23). Deep ploughing with and without paper waste increased N leaching from 105 kg/ha (normal ploughing or surface incorporation) to 172 kg/ha (S. E. d= 27). Measurements of nitrate leaching using deep soil cores showed a less clear cut effect. Nitrous oxide (N2O) emissions were very high immediately after paper waste was ploughed in to a depth of 35 cm. Non–significant increases in biomass N content were measured in the spring following paper waste application. There was no significant reduction in plant N uptake in subsequent crops. Removal of above–ground crop residues did not have a significant effect on nitrate leaching or N2O losses. In the calabrese experiment, application of 40 t DM paper mill waste/ha followed by summer cropping with iceberg lettuce caused a decrease in N leaching (measured using deep soil cores) from 227 to 152 kg/ha (S. E.d= 22, mean of all cultivation treatments).

Notizen: Abstract. In a long-term experiment, soil physical properties were studied after 20 annual cycles of maize-wheat-fodder cowpea cropping with annual application of inorganic fertilizers and farmyard manure (FYM). Weeds were controlled by hand or by the use of herbicides. The hand weeding treatment resulted in a lowering of the bulk density of the surface layer (0-15 cm) and a significant increase in the subsurface (15–30 cm) density. Application of FYM significantly increased the soil organic carbon (OC), infiltration rate, water retention, aggregation and aggregate stability in water. Application of inorganic fertilizers had small but statistically significant effect in increasing soil OC.

Notizen: Book Reviewed in this article:A Place Against Time–Land and Environment in the Papua New Guinea Highlands By P. Sillitoe.

Notizen: This paper considers the magnitude of the human capital investment required to offset the increase in the inequality in labour earnings in the US economy since 1979. It considers the ineffectiveness of government training policies, the effectiveness of private sector training and the conflict between economic efficiency and the work ethic. It also considers revisions of the tax code. The importance of the distinction between the long view and the short view in analysing human resource policies is emphasised. JEL classification: J24, I28, H40.

Notizen: This paper uses data from the two waves of the UK Retirement Survey to present a detailed descriptive analysis of the retirement behaviour of older men. The main motivation for doing this is the fall in the employment rates of older men over the last 20 years. A comparison of the labour market behaviour of men with and without an occupational pension suggests that increases in the coverage and levels of occupational pensions may not be enough to explain the long-term trends in labour market behaviour, but that there are important differences in the retirement experiences of the two groups. JEL classification: J26.

Notizen: Expectations regarding the future state of the public finances are vital for public policy formation. The UK experience has been that forecast of the PSBR have been beset with problems since the mid-1980s. Independent assessments of the accuracy and plausibility of public finance forecasts are an important check on government forecasts and serve to increase public debate over government finance issues. We examine the success of various possible methods available to those outside government. JEL classification: E6, H1, H6.

Notizen: Abstract. In a laboratory study, 15N ammonium fertilizer uptake and rice growth was determined in a non-acid sulphate marine soil (Typic Tropaquept) and an acid sulphate soil (Sulfic Tropaquept). Acid sulphate sensitive (IR 26) and acid sulphate tolerant (IR 46) rice varieties were grown in soil suspensions incubated at four Eh levels (+500, +250, +50, and -150 mV) in microcosms for three weeks. The results showed that rice grown in non-acid sulphate marine soils gave slightly better dry matter weight of 1.8g/pot, greater 15N uptake of 12.8 mg N/pot, and higher total N uptake of 38.4 mg N/pot than under acid sulphate soil conditions indicating the non-acid marine soil is more favourable to rice culture. Growth as measured by weight of dry matter was significantly reduced from 2.1g/pot under oxidized condition (+500 mV) to 0.8g/pot under highly reduced condition (-150 mV). N uptake by rice was significantly reduced from 16.9 mg/pot at + 500 mV to 4.5 mg N/pot at -150 mV Total N uptake also decreased with decreasing Eh. Growth, 15N uptake and total N uptake by acid sulphate tolerant rice, IR 46 were significantly higher than the acid sulphate sensitive rice variety, IR 26. Under highly reduced soil conditions (-150 mV), growing rice in acid sulphate soil would require additions of lime, intermittent irrigation and/or mid season drainage in order to increase soil redox potential and remove toxic substances.

Notizen: Book reviewed in this articles: Take-all disease of cereals: a regional perspective. By Hornby, D., Bateman, G.L., Gutteridge, R.J., Lucas, P., Osbourn, A.E., Ward, E. & Yarham, D.H.

Notizen: Abstract. This paper investigates the ways in which some bedouin in the Nubian Desert of southeastern Egypt take decisions about both the choice of site for cultivation and the subsequent management of their soils. It explores the complementarity of formal and informal sciences and how each might profitably inform the other. Results show that the bedouin understand the physical limitations and nutrient supply properties of soils, but not aspects such as pH. Decisions on the choice of cultivation site are often made with regard to other perceived risks, such as soil loss and intermittent inundation, rather than just soil quality. It is also apparent that there exists among bedouin a plurality of indigenous knowledge mediated by factors such as experience, wealth levels, household circumstances and production priorities. Understanding indigenous knowledge is essential in helping to develop better use of the soil in this area, about which little is known and which has only a short history of small scale cropping.

Notizen: Book reviewed in this articles: Agroforestry for soil management. By A. Young.

Notizen: Book reviewed in this articles: Biological indicators of soil health. Edited by C.E. Pankhurst, B.M. Doube & V.V.S.R. Gupta.

Notizen: Abstract. Soil cores from river marginal wetlands in the UK, France and Ireland, sampled and contained within PVC piping, were flooded with nitrate-N enriched water. Half of the cores were sterilized prior to flooding to destroy the denitrifying bacteria. The change in nitrate-N concentration in the floodwater was measured over time. It is argued that the observed nitrate depletion rates (from 0.4 to 2.3 kg/ha per day) may be identified With 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.

Notizen: 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.

Notizen: Abstract. We report on a study aimed at assessing improvements in soil structure that developed when a reduced ground-pressure traffic system was introduced onto grassland previously compacted by conventional machinery traffic, and when a zero traffic system was introduced on land previously under a reduced ground-pressure system. Increases in the volume, average size, and number of macropores, measured by image analysis, together with decreases in vane shear strength indicated structural improvement in soil under the substitute traffic systems relative to the same soil in the original systems. A smaller content of organic matter in the soil of the substitute systems than in the original systems was attributed to improved aeration and greater earthworm activity in the former.

Notizen: Abstract. The potential for degraded physical properties of soil to regenerate naturally after exclusion of grazing animals was examined at a long-term stocking rate trial near Armidale, New South Wales, Australia. Unsaturated hydraulic conductivity was measured before grazing was excluded, and after 7 months and 2.5 years’ grazing exclusion. These data were compared with controls grazed at 10,15 and 20 sheep/ha. After 2.5 years, there were significant increases in unsaturated hydraulic conductivity at 5 and 15 mm tension in the ungrazed treatments compared with the grazed controls. The unsaturated hydraulic conductivities and bulk density of surface soils under pasture which had been ungrazed for 2.5 years were comparable to those where the pasture had been ungrazed for 27 years. We speculate that the natural amelioration of soil physical properties in these soils was due to biological activity and wetting and drying cycles, in the absence of the compactive effect of animal treading.

Notizen: Abstract. Nitrate leaching measurements in Denmark were analysed to examine the effects of husbandry factors. The data comprised weekly measurements of drainage and nitrate concentration from pipe drains in six fields from 1971 to 1991, and weekly measurements of nitrate concentration in soil water, extracted by suction cups at a depth of 1 m, from 16 fields in 1988 to 1993. The soils varied from coarse sand to sandy clay loam.The model used for analysing the data was: Y= exp (1.136–0.0628 clay+ 0.00565N +crop) D0.416, with R2= 0.54, where Y is the nitrate leaching (kg N/ha per y), clay is the % clay in 0-25 cm depth (%), N is the average N-application in the rotation (kg/ha/y) and D is drainage (mm/y). The most important factor influencing leaching was the crop type. Grass and barley undersown with grass showed low rates of leaching (17-24 kg/ha/y). Winter cereal following a grass crop, beets, winter cereals following cereals and an autumn sown catch crop following cereals showed medium rates of leaching (36-46 kg/ha/y). High rates of leaching were estimated from winter cereals following rape/peas, bare soil following cereals and from autumn applications of animal manure on bare soil (71-78 kg/ha/y). Estimates of leaching from soil of 5, 12 and 20% clay were 68, 44 and 26 kg/ha/y, respectively. Leaching was estimated to rise significantly with increasing amounts of applied N.The model is suitable for general calculations of the effects of crop rotation, soil type and N-application on nitrate leaching from sandy soil to sandy clay loarns in a temperate coastal climate.

Notizen: This paper applies modern concepts from the theory of public goods to indicate why progress has been made with respect to some global and regional public goods (for example, cutting sulphur emissions) but not with respect to others (for example, cutting greenhouse gases). Factors promoting collective action at the transnational level include the removal of uncertainty, a high share of nation-specific benefits, a limited number of essential participants and the presence of an influential leader nation. The impact of public good aggregation technologies on the future provision of transnational public goods is related to the trend in world-wide income inequality. Principles are presented for designing supranational structures for addressing transnational public good problems. JEL classification: H41, D70, Q20.

Notizen: The newly elected Labour government has pledged to ‘reinvigorate the Private Finance Initiative’, as part of the new emphasis on ‘public/private partnerships’ in the delivery of core public services. This article assesses the merits of using private finance to deliver public services against three criteria: whether it will lead to additional investment in social infrastructure, whether it represents good value for the taxpayer's money and whether the use of private finance will reduce the public sector's flexibility to pursue its public service objectives. JEL classification: H54, H11.

Notizen: This paper uses two waves of the UK Retirement Survey to look at how incomes change during retirement. We concentrate on men aged 65–69 and women aged 60–69 in 1988–89 and look at how their incomes change over the following five years. Overall, we find a considerable degree of stability in real incomes. We use the panel data to look at the incomes of widows before and after they are widowed and find that, for this group of relatively young widows, their low incomes are in large part determined by the fact that it tends to be the relatively poorer husbands who die among this age-group. Finally, we consider the most important component of private income — occupational pensions — separately. We find a strong relationship between pension level and the probability of indexation — pensions that start low are less likely than higher pensions to keep up with inflation. JEL classification: D31, H55

Notizen: In this paper, we present a new model of UK public finances which aims to shed light on recent problems of forecasting the PSBR. The main elements of public spending are treated as endogenous variables which rise in line with GDP over the medium term. Also, the cyclical response of public borrowing to rises in the level of economic activity is more muted when growth is export-led than when it is consumer-led. These two features go a long way towards explaining the rapid deterioration of public finances in the early 1990s and the slow pace of improvement since 1993. JEL classification: C53, E62, H62.

Notizen: A recurring issue in indirect tax design — most obviously, but not only, for goods traditionally subject to heavy excises — is the appropriate balance between specific and ad valorem taxation. Recent work has developed new perspectives on the issue, which is also one of the oldest in the formal study of public finance. This paper provides a broadly non-technical account of the central considerations that arise in choosing the balance between specific and ad valorem taxation, reviewing and somewhat extending the lessons of theory and experience. There emerge clear presumptions as to the relative effects of the two kinds of tax on such attributes as price, profits, product quality and variety. But the socially optimal balance between them is likely to be quite sensitive to the characteristics of the market at issue. JEL classification: h21, H22.

Notizen: The 1986 Social Security Act introduced far-reaching changes to the supplementary pension environment in Britain, encouraging the growth of defined contribution pension plans and especially personal pensions. This paper examines the pattern of supplementary pension coverage of employees in Britain five years after the implementation of the Act, using cross-sectional data from the Family Resources Survey 1993–94. Two-thirds of employees in Britain are covered by private contracted-out pension scheme. Employer-provided defined benefit pension schemes remain the dominant type of supplementary pension scheme. The growth of personal pension plans is more marked among manual, less-skilled, workers in smaller establishments. The paper concludes that, in the absence of further pension reform, adverse labour market conditions will exert downward pressure on private pension coverage. JEL classification:I38, J32, J38.

Notizen: Starting in 1998, the electricity market in England and Wales will be opened up to full competition, and all consumers will be allowed to choose their electricity supplier. This promises to result in lower prices, but there will be additional transactions costs exceeding £100 million a year for the first five years. Relative to a counterfactual without competition, there are likely to be large transfers from electricity companies (and the coal industry) to consumers, but the companies lose more than consumers gain. This conclusion might be reversed if competitive pressure leads to significant additional cost savings in the future. JEL classification: L94

Notizen: Abstract. An increasing proportion of P reaching surface waters appears to be derived from agricultural land; apportioning the relative contribution to particular farming systems is not straightforward. The majority of farms in the UK operate on the basis of an annual agricultural P surplus, the size of which varies across different farm types. Particularly high values (〉20kg ha-1) are commonly associated with intensive-livestock production and the lower values (〈10kg P ha-1) with arable farms. The geographical divide between the predominance of arable cropping in the east and livestock enterprises in the west of the UK should result in an uneven pattern to the distribution of annual P surplus. The expected cumulative effects of this surplus should be a noticeable increase in total and extractable soil P concentrations, but this is not readily apparent. While evidence from experimental plots suggests a relationship between the concentration of available soil P and that present in drainage waters, extrapolating this information so that it can be useful at the scale of a whole catchment is difficult. The loss of P from agricultural land is controlled by factors which are independent of the size of the annual P surplus. The pattern of P cycling, together with the dominant loss pathways, differ greatly between livestock and arable farming systems. Proportioning the contributions that either increased soil erosion arising from changing agricultural practices or the cumulative effect of a P surplus have had upon P loss is a necessary prerequisite to effective management.

Notizen: Abstract. Agriculture contributes significant loads of P to surface waters. The reductions in these diffuse P inputs necessary to help prevent eutrophication problems and/or assist in the restoration of water quality will require controls over both nutrient inputs and their subsequent transport in land runoff. Specific mitigation options include nutrient budgeting, input management, soil conservation, land use management and the establishment of riparian, and other buffer zones. The variable nature of diffuse P loss suggests that the best approach to control is through integrated management at a range of scales. Critical control concepts at the farm level include targeting source areas adequately, maintaining P input loading rates within recommended limits and avoiding high-risk management actions. Since eutrophication is a natural phenomenon and with potential conflicts with the need to meet production targets and/or minimize loss of other nutrients (N), some assessment of acceptable levels of P loss, of cost effectiveness of options and some prioritization of goals are necessary to find optimal solutions. As the requirements of individual waterbodies differ, these solutions need to be site specific and their successful adoption requires an appreciation by farmers of the importance of minimizing agricultural P loss both as individuals and collectively within a catchment.

Notizen: Abstract. The interactions of P with soils and sediments are examined in the context of transport processes from land, through rivers to estuaries and coastal waters. In soil erosion, selective size fractionation and preferential sorption to finer solids is crucial in the transport of P to water courses. Problems in quantifying the sorption affinity and equilibrium phosphate concentration (EPC) of mixtures of different soils and sediments are identified. Riverine transport of P by suspended solids is usually very important and examples of the changes in the amount and composition of particulate P (PP) concentration during storm events are discussed. Increased P content of solids during the first autumn storms, probably reflect the resuspension of accumulated stream bed-deposits. The fate of P in estuaries and their importance as possible long-term sinks of P are discussed. The relatively high concentrations of dissolved P associated with riverine inputs are to some extent buffered by the relatively high concentrations of suspended sediments resulting from tidal flows. Phosphorus may be released during transport to the sea due to decreases in the EPC, increases in salinity and release from bottom sediments as a result of low oxygen conditions.

Notizen: Abstract. Organic manures are an important source of P which can make a significant economic contribution to farm fertilizer policies. In the region of 119000 tonnes of P are returned annually to UK agricultural land in the form of manures collected and handled on farms, with an estimated 66000 tonnes of P applied to tillage land and 53000 tonnes to grassland.Previous research on the utilization of manure P has tended to indicate a lower efficiency compared to inorganic fertilizer P in the season following application, but in the longer term manure and fertilizer P can be regarded as equivalent. Failure to adequately account for manure P additions to the land may result in soil enrichment which could increase the agricultural contribution to eutrophication, as a result of surface runoff or leaching.Recent research has indicated that the current guidelines for minimizing runoff losses following the land spreading of manures are generally soundly based. However, there is a need for further research where manures are applied to cracking clay soils with underdrainage, and where rainfall soon after slurry application can increase surface runoff.The careful cycling of manures within a properly devised fertilizer plan should minimize the risk of unnecessary soil P enrichment and subsequent leaching losses by restricting topsoil extractable P levels to less than 70 mg I-1.

Notizen: Abstract. The Skokloster and Stockholm Environmental Institute (SEI) approaches were applied to the assessment of 145 soils of the South African highveld region in terms of sensitivity to acid deposition. The critical load class calculated by variants of these methods was compared with the acid neutralizing capacity (ANC) determined by pH measurement of soil suspended in a dilute acetate buffer solution. This rapid index of ANC correlates well both with ANC determined by an established but more laborious method which involves titration and equilibration of soil with HCl, and with a number of soil properties related to base status. The correlation between Skokloster or SEI critical load classes and ANC was weak. It was concluded that ANC determination would be a preferable basis for classifying these soils in terms of their sensitivity to acid deposition, since the method is direct and integrates the contribution of various soil properties to acid sensitivity instead of requiring the relative contribution to be calculated according to somewhat arbitrary weightings given to broadly defined classes of soil properties.

Notizen: Abstract. Emissions of ammonia (NH3) and nitrous oxide (N2O), and nitrate (NO-3) leaching were measured in two field experiments following application of pig slurry at rates corresponding to 83–96 kg NH4-N ha-1 before sowing. In spring and in autumn 1994, slurry was applied by four methods: trenching (T), shallow injection (S), band spreading immediately followed by harrowing (B/H) and band spreading (B). NH3 emission measurements were made during the first week after application in both experiments. In the spring experiment N2O emissions and NO-3 leaching were measured during 6 and 52 weeks after spreading respectively, and during 11 and 33 weeks after spreading in the autumn experiment. In spring, the increased N2O emissions (i.e. control subtracted) ranged from 0.27% (T) to 0.45% (B/H), and in the autumn study from 0.92% (T) to 1.14% (B/H), of applied NH4-N, although showing no statistically significant differences. In order to validate the chamber measurements, a ‘megachamber’(21 m2) was used together with an infrared spectrometer. The emissions agreed well for (B/H), while (B) resulted in lower emissions compared with the smaller chambers. Emissions of NH3 were about one order of magnitude higher. In spring, (B) gave the highest emission, reaching 19.5% of applied NH4-N, whereas (S), and (B/H) gave the lowest emissions, reaching 1.2 and 3.5% of applied NH4-N, respectively. NH3 emissions in autumn were 15–20% lower compared with spring. In spring the increased nitrate leaching ranged from 10.1 (T) to 24.9 kg ha-1 (B/H) and from 29.5 (B) to 37.8 kg ha-1 (T) in the autumn experiment, showing no statistically significant differences. Estimations of indirect N2O emissions due to ammonia deposition and nitrate leaching, suggested that the N2O contribution from NH3 deposition was relatively small, while the indirect N2O emissions from NO-3 leaching were of the same order of magnitude or higher than the direct N2O emissions.

Notizen: Abstract. In 1996 conservation tillage was used on nearly 36% of the cropped area of the USA. This level has remained relatively unchanged over the past few years. The use of conservation tillage varied by crop and was dependent on site-specific factors including soil type, topsoil depth, and local climatic conditions. A number of economic, demographic, geographic, and policy factors have affected the adoption of conservation tillage. While it was not possible to quantify exactly the impact of these factors, it was clear that management complexities and profitability are key factors impeding an increase.

Notizen: Abstract. The effects of long-term waste water irrigation on soil fertility and nutrient supply to alfalfa (Medicago sativa) have been investigated in an area near Mexico City Waste water irrigation has improved the nutrient balance of the soil in respect of total nitrogen and available phosphorus. In contrast Na has displaced Ca and diminished the Ca saturation of the soil. In consequence, Ca in alfalfa tissue has decreased and phosphorus and sodium increased after 80 years of waste water irrigation. Estimates of the N-balance suggest that substantial amounts of N are being lost, probably with consequent eutrophication of the groundwater.

Notizen: Abstract. Results are presented from three years (1992-1995) of a field leaching experiment on a sandy soil in south-west Sweden. Plots of spring cereals, either with or without an undersown perennial ryegrass catch crop, were compared for nitrogen leaching and nitrogen status in soil. Both treatments were ploughed in spring, and other tillage regimes were also identical. Measurements of nitrogen leaching from drains, nitrogen uptake in crops and mineral nitrogen in the soil were made. Two coupled, simulation models, which describe water flow and nitrogen transformations and transport in soil, were used to interpret data and to calculate the nitrogen budget and nitrogen mineralization in the soil.Nitrogen leaching was 40 50% less in the catch crop treatment compared with the control during years when the establishment of the catch crop succeeded. In the third year of the experiment nitrogen leaching was actually greater in the catch crop treatment (7 kg N/ha). This increase was caused by a poorly established catch crop coinciding with enhanced mineralization of previous catch crop residues. There was no simulated change in soil organic nitrogen in either of the treatments. Simulations showed increased nitrogen mineralization during April-July after incorporation of plant material in spring, especially in the catch crop treatment. However, the increased nitrogen mineralization probably occurred too late for the released nitrogen to be fully available to the main crop.

Notizen: Book Reviewed in this article:Principles and Practice of Soil Science (Third Edition) By R. E. White.

Notizen: Abstract. Since 1980 soil erosion by water on agricultural areas has been measured in plot experiments conducted at the Department of Soil and Water Sciences at the Agricultural University of Norway. Meltwater in spring is the most serious erosive agent but rainfall on nearly saturated soil and hare soil also has a considerable erosive effect. Erosion as a result of heavy rainfall in the growing season occurs occasionally. A high proportion of water-stable aggregates and a high content of clay and humus are characteristics of a soil with good resistance to emsion. Tillage has a strong influence on soil loss and it has been found that spring tillage reduces the annual soil loss by 90% compared with autumn ploughing.

Notizen: Abstract. There is environmental concern about the increasing land application of dairy shed effluent in New Zealand. To minimize groundwater contamination by applied nutrients and pathogens it is desirable to avoid preferential flow through topsoils. Our objective was to determine an irrigation rate that retained applied effluent in the topsoil of two commonly irrigated New Zealand soils. In a field experiment, well drained Horotiu soils and poorly drained Te Kowhai soils were irrigated with a pyranine dye/KBr tracer solution at four rates (5, 10, 15, 20 mm/h) using a drip-type rainfall simulator. Twenty minutes after irrigation ceased the soil was excavated horizontally at 25 or 50 mm intervals, and photographed under UV light until no further fluorescence was vishle. Each layer was also analysed for bromide content, without subsampling. The wetting pattern was uneven in both soils as leachate moved preferentially through worm channels and structural cracks. Preferential flow was greatest in the Te Kowhai soil and increased at faster application rates. Dye fluorescence was curvilinearly related to bromide concentration. At both study sites, maintaining the irrigation rate at 〈inlineGraphic alt="leqslant R: less-than-or-eq, slant" extraInfo="nonStandardEntity" href="urn:x-wiley:02660032:SUM96:les" location="les.gif"/〉 10 mm/h minimized leachate movement into the subsoil. Pulsed irrigation at faster rates was not retained in the topsoil.

Notizen: Abstract. We investigated whether a Na-K polyacrylate polymer could be used to remediate a sandy soil artificially contaminated with copper. An experiment, carried out in solution culture, showed that ionic copper was rapidly trapped within the polymer to a maximum content of c. 190mg Cu g -1 dry polymer, the proportion needed for chelation of each copper ion by four carboxylic groups present in the polymer chains. Cu-EDTA was not retained by the polymer. Growth of perennial rygrass in 10 kg pots was stimulated in the gel-amended soil, and even in the pots with the highest levels of copper, growth was much less impaired than in pots without polymer. Copper concentrations of the shoot.; were smaller in the plants cultivated in the amended soil. Water extractable copper was considerably reduced in the contaminated gel-amended soil and polymer particles removed from the soil were shown to contain high levels of copper.

Notizen: Abstract. The fragile soils at the transition between semiarid and arid areas are continuously threatened by human activity, which frequently involves the elimination of plant cover. We studied the impact of vegetation removal on soil characteristics in senmiarid Mediterranean Spain using two plots (15 m ± 5 m), installed on a north facing slope of 23%. Vegetation was removed from one of the plots (disturbed plot), and changes in the soil characteristics were compared with an undisturbed control plot. Fifty-five months after vegetation removal the organic carbon content decreased by 35%, the percentage of stable aggregates by 31% and soil bulk density increased by 8%. The models that best represented the changes of these parameters with time were linear equations. There were no significant differences between the water retention capacity or saturated hydraulic conductivity of the treatments. The rapid loss of soil organic matter and the consequences in terms of physical soil properties were considered to be the main factors in soil degradation. No symptoms of natural recovery were observed in the disturbed plot and the tendency was for a steady deterioration in soil behaviour. This means that human activity or climatic change leading to less vegetation could result in irreversible soil degradation in semiarid areas.

Notizen: Abstract. A field experiment was conducted over two years in one of the mountain Alfisols of the Western Himalayas to study the effects of phosphorus and mulching on phosphorus use efficiency (PUE) and productivity of wheat (cv. S-308) at difference growth stages. The source of phosphorus was single superphosphate at 0, 26, 52 and 78 kg P/ha whereas the sources of mulching materials were pine needles (Pinus longifolia), lantana weed (Lantana camara) at 8 t/ha and transparent polyethylene sheet compared with no mulch.The phosphorus use efficiency (PUE) at tillering, flowering and harvesting was greatest at the lowest dose of P and decreased as the P levels were increased. However, the increased levels of P up to 78 kg/ha, significantly improved the dry matter yield at tillering stage (30%) and flowering stage (93%) and also the grain yield (139%) and straw yield (148%) at the harvest stage. The application of mulching materials in general, and polyethylene in particular, significantly increased the phosphorus use efficiency and the productivity of wheat by 27% at tillering stage; 17% at flowering stage, and by 98 and 110% in the case of grain and straw yield at harvest stage.Although the polyethylene mulch effect was physically superior to the other materials, the latter gave greater financial returns. Consequently, the economic optimum application of P in association with 8 t/ha of lantana mulch was found to be 53 kg/ha over two years, whereas, in the absence of mulching, it was 58 kg/ha.

Notizen: Abstract. An empirical model was developed for prediction of annual average nitrate leaching as affected by the long-term rate of N fertilization and crop type. The effect of N fertilization was estimated from annual values of nitrate leaching obtained from two Danish investigations of drainage from pipe drains with four rates of N fertilization on a loamy sand and sandy clay loam from 1973-89. The effect of crop at normal N fertilization was estimated from 147 observations of annual nitrate leaching obtained from field measurements. The nitrate leaching model consists of a relative N fertilization submodel and an absolute submodel for specific combinations of crop, soil and drainage at the normal rate of N fertilization. The relative submodel is Y/YlN= exp[0.7l(N/ N1– I)], where Y is the nitrate leaching (kg N/ha per year) at fertilization rate N, and YIN and N1 are the corresponding values at the normal rate of N fertilization. The relative submodel is valid for cereals, root crops and grass leys fertilized with mineral fertilizer at N/N1 〈 1.5, and on the prerequisite that the fertilization rate N has been constant for some years. To illustrate the use of the relative leaching submodel, estimated values of YIN corrected to mean annual drainage for 1970 to 1990 in Denmark for spring cereals and grass on sandy and loamy soils are given as input to the relative leaching submodel. The model can be used for sandy to loamy soils to estimate the mean nitrate leaching over a number of years.

Notizen: Using data from the Luxembourg Income Study, I study the sensitivity of cross-national income poverty comparisons to the method in which poverty is measured. Absolute poverty comparisons that keep the purchasing power at the poverty line constant across countries lead to conclusions that differ from relative poverty comparisons in which the real value of the poverty line varies with average income. The absolute poverty ranking of countries also varies as the real value of the poverty line is lowered. Cross-national differences in household characteristics are largely irrelevant in explaining poverty differences.

Notizen: Using longitudinal data which include real estate wealth, financial assets as well as consumer durables, changes in the distribution of wealth in Sweden are related to major changes in asset prices and in incentives to hold various assets in the 1980s and the beginning of the 1990s. Our analysis of the mobility of wealth indicates that decile mobility is higher in Sweden than in the U.S., while the analysis of who is gaining and who is loosing shows results similar to those of previous studies.

Notizen: We demonstrate that the criteria put forward by Atkinson and Bourguignon (1987) can be satisfactorily applied to the analysis of poverty even when the demographic composition of society and the definition of poverty change over time. We show that they provide both sufficient and necessary conditions for any robust conclusions concerning the changes in welfare and poverty. We apply these criteria to a set of data tracking annual income distribution movements in France from 1977 to 1994. The Atkinson and Bourguignon criteria posit that recent changes in poverty are a function of macroeconomic fluctuations in activity.

Notizen: This study focuses on the role of foreign-born households in Canada's asset market. An empirical analysis of wealth accumulation is conducted for a large sample of Canadian households circa 1977–84. This study period reflects a change in Canada's immigration policy which resulted in immigration Rows switching from Europe to Asia. A life-cycle framework is used to examine wealth accumulation behaviour of the foreign-born vis-à-vis Canadian-born households. The empirical results confirm the existence of an inverted ‘U’-shaped wealth-age profile for both Canadian and immigrant households. However, the 1977 results show that the rate of wealth accumulation is higher for the immigrant household than the Canadian-born household in pre-retirement years, while the 1984 results reveal the opposite. After retirement, the rate of wealth dissipation is slower for Canadians than for foreign-born households. Only the 1984 results indicate that public social security wealth displaces household savings for both the Canadian-born and the foreign-born by a small amount. Finally, an immigrant household exhibits a stronger transfer motive within a family than a Canadian-born household regardless of year tested.

Notizen: This paper investigates the importance of increases in the productivity of producing capital in estimates of the profit rate decline which occurred in the United States during the period 1950–90. We find that, when profit rate measures take into account the increasing productivity of producing capital stock (as measured by the embodied labor required to produce it), the observed decline is about one-half that found using conventional measures of profit. This finding has important implications for interest rate and investment policies.

Notizen: In this study we consider two panels of wage-earners, from 1974 to 1988, for Italy and France respectively. The international perspective and the availability of micro-data are particularly interesting for they allow us to address individual characteristics as well as national specificities. In the empirical analysis a partitioning of the earnings distribution by deciles is used and the overall hierarchical mobility of individuals is investigated. Transition matrices are computed in order to compare wage formation and mobility processes across countries, in the period under investigation. A rich battery of mobility indices is presented and the relations between them are studied.The paper addresses several different issues and compares the results across countries. First, the evolution of earnings and the relative wage profiles are compared across countries. Second, the heterogeneity issue is addressed and some structural characteristics of the sample are studied, namely: cohort and gender differences in earnings.

Notizen: To account for the fact that a household's needs depend on its size and composition most studies on income inequality adjust the observed household incomes by equivalence scales. However, since the rationale for choosing a specific scale is rather vague the importance of testing the sensitivity of income inequality estimates to choice of equivalence scales has long been acknowledged. The sensitivity studies in the literature are restricted to equivalence scales that do not depend on the income level of the reference household which means that the effect of a rise in the household size on the scale rate does not depend on whether the household is poor or rich. By using Norwegian micro-data it is shown that the introduction of an income-dependent scale produces results that are in conflict with the widespread view of robustness of results to choice of equivalence scales.

Notizen: The level of earnings inequality and its change during the 1980s in Portugal are analyzed, relying on several inequality measures and on international comparisons to generate insight into their patterns. A high level of inequality at the beginning of the eighties is detected, together with a pronounced rise in wage dispersion, brought about by growing inequality at the top. Changes taking place within economic activities, possibly technical progress, are the main forces driving these changes in the wage pattern, while demographic forces, as well as international trade, which could have generated shifts in the demand for labor across economic activities, should be dismissed as explanations for the rise in labor market inequality in Portugal from 1983 to 1992.

Notizen: An important application of national accounts is in the formulation of socio-economic policy. This paper starts out with a discussion of the current situation in the Netherlands. Subsequently, it identifies several universal trends (more micro-oriented policy formulation, globalization, the rise of the flexible service economy and the increasing intertwinement of economic, social and environmental policies) and outlines how the national accounts might be adapted and extended so as to enhance its role as the core information system for policy formulation at the macro-and meso-level.

Notizen: There are major methodological and practical problems in comparing the performance of capitalist and communist economies. They have been most carefully analysed for the former Soviet Union, for which there was a huge research input, mainly by the CIA. The CIA effort had considerable merit, particularly in assessing Soviet rates of growth. Unfortunately, it was terminated in 1991, partly because it suffered from unduly harsh criticism, partly because its political relevance waned. However, the CIA archives remain an important source for the study of comparative economic growth. It would be extremely useful if they were opened to scholars, a serious loss if they were destroyed.

Notizen: This paper analyses how consumption inequality within a fixed cohort grows with age using Japanese household microdata. Following the method developed by Deaton and Paxson (1994), we obtain the following results. First, consumption inequality starts to increase at the age of 40. Second, younger generations face a more unequal distribution from the beginning of their life-cycle. Third, half of the rapid increase in the economy-wide consumption inequality during the 1980s was caused by population aging, while one-third was due to the increasing cohort effect. The paper compares the above results with those of Deaton and Paxson.

Notizen: In this paper, we consider reforming the tax system to a comprehensive income tax model in order to amend the differential treatment of income sources. Our simulation analysis shows that the tax reform improves the effectiveness of the tax system on the redistribution of all sources of income including earned income, financial wealth income, and imputed rent. The analysis of incidence of the tax reform suggests that the tax burden for young renters decreases the most and that for young loan-free land owners increases the most through this tax reform.

Notizen: This paper analyses the behaviour of productive efficiency in the Spanish regions for the period 1964–93. From a growth accounting approach, it describes the regional evolution of total factor productivity (TFP'), based on a private inputs production function. A stricter measure of efficiency is then quantified, which is not equivalent to Solow's residual, since public capital is included in the production function and constant returns to scale are not imposed. Finally, on the basis of the measures of total factor productivity and efficiency, the study discusses the existence of technological convergence among Spanish regions and the role played in it by public capital.The renewed interest in the analysis of the process of growth reflected in economic literature in recent years has also occurred in the case of the Spanish economy, with some peculiarities which are worth mentioning. In the 1980s, two important institutional changes took place: a profound political and administrative decentralization, the regions now being autonomous in many decisions on public expenditure, and the incorporation of Spain into the European Community, which as it is well known has a powerful regional policy. Both changes have meant that the analysis of regional economies, and especially their growth paths, have received much more attention from politicians and economists, and even from the population in general. In particular, intense discussion has taken place regarding the effects of development policies and on criteria for geographical distribution of infrastructures. In both cases, much attention has been paid to discussing their capacity to contribute to convergence among the different regions.As a consequence of this greater interest in the analysis of growth from a regional perspective, efforts have also been made to improve the relevant statistical information. In particular, statistical series have been drawn up for investment and accumulated capital stock in each region, both private and public.' This information, only recently available and the first of its kind, as far as we know, in the European regions, substantially broadens the possibilities of research into the Spanish case in this field, where before not even the simplest exercises in growth accounting could be attempted. Further-more, since the series now available allow the time dimension of growth analysis to be combined with the regional dimension, it is possible to work with a panel of data and apply the corresponding techniques.This article analyses the growth of the Spanish economy over the period 1964–93, during which it can be observed that the per capita income levels of the Spanish regions converged. The objective of the study is to evaluate this process of convergence in income from the perspective of the productive efficiency of the regions, in three different ways. First, Section I considers the importance of the contributions of the private factors of production and of improvements in total factor productivity to the growth of output. Secondly, section II studies the existing relationship between the standard measure of efficiency (Solow's residual or TFP') and a stricter measure when the endowments of public capital are considered. Section III analyses whether or not the convergence in per capita income

Notizen: We propose that labor income indices be used to define settlements in many contracts, such as labor contracts, indexed bonds, or income securities. We discuss the issues in producing labor income indices for such uses, and develop prototype indices using US. data from the Panel Study of Income Dynamics (PSID). People are grouped by a clustering algorithm based on an estimated transition matrix between jobs, by education level, and by skill category. The groupings are defined so that few people move between them. For each grouping we generate a labor income index (1968–87) using a hedonic repeated-measures regression method. The indices show substantial variability through time, confirming the potential importance of the use of such indices in contracts. There is also substantial variability across groupings, as for example between the agriculture/labor grouping and other groupings, confirming the importance of using the grouping indices rather than aggregate indices in contracts.

Notizen: Household equivalence scales are often used to help perform welfare comparisons across households with different demographic composition. Abstracting from the problems of value judgments and ethical standards, the use of equivalence scales to perform welfare comparisons still faces several measurement problems, namely the identification problem and the endogeneity problem. This paper introduces and estimates an unconditional demand system that simultaneously addresses these two problems. By explicitly considering the demand for leisure, and the fact the household can choose some of its demographic characteristics, we deal with the endogeneity problem and obtain consistent estimates. We identify unconditional equivalence scales by estimating the demand for endogenous demographic variables along with the demand for leisure and consumer goods. More general equivalence scales allowing for better comparability are estimated and used for welfare comparisons.

Notizen: This paper uses the PSID to assess the changes in earnings mobility and to compare the changes in cross-section and long-run inequality in the 1970s and 1980s. Previous inequality studies have primarily used measures of cross-section inequality. However, long-run inequality depends not only on cross-section inequality, but also on the degree of earnings mobility, which equalizes earnings over time. I find that earnings mobility increased during the 1970s, but fell during the 1980s. Consistent with this result, the increase in cross-section inequality overstated the true increase during the 1970s, but understated the true increase in inequality during the 1980s.

Notizen: This paper discusses how to take assets into account in the measurement of poverty. First asset holdings of current income-poor households are described. Second, the effects on the measured incidence of poverty of two methods to combine income and assets into a single index of economic resources are presented. Third, since the majority of income-poor households do not have assets of much value except for their home, I reconsider the matter of the treatment of housing costs in the measurement of poverty. A method where poverty thresholds are adjusted according to home tenure status is favored, and results of this method are shown. Data are used from the Belgian Socio-Economic Panel, wave 1992.

Notizen: In 1991 Statistics Netherlands introduced their early flash estimates of the Quarterly National Accounts. In this article we examine a new, faster flash estimate, some three to four weeks earlier. The gain is made by using a simple regression technique and incomplete data. To compensate for the lack of data, information on the number of working days and shopping days was added to the regression. The inclusion of these calendar aspects significantly affect GDP growth: 0.30 percent point extra GDP growth for one extra working day, and 0.17 percent point for one extra shopping day.The cost of an earlier estimate is a decrease of reliability. The probability of a forecast error of over 0.5 percent point will be about 26 percent, compared to 12 percent for the official flash estimate.

Notizen: This paper uses Canadian cross-sectional income and expenditure data to examine changes in the distribution of family income and family consumption during the period 1978 to 1992. Family consumption data are analyzed because in the presence of intertemporal consumption smoothing, the cross-sectional distribution of consumption may characterize the distribution of lifetime wealth. I find that both Canadian family income inequality and Canadian family consumption inequality moved countercyclically. In addition, both Canadian family income inequality and Canadian family consumption inequality trended upward over the period; however, the change in family consumption inequality was much smaller than the change in family income inequality, suggesting that inequality in the distribution of lifetime wealth may have changed much less than is suggested by changes in the distribution of income.

Notizen: This paper examines wage differentials at the firm level in Chile and Brazil, using data for 1985 and 1991, and 1987 respectively. The high level of disaggregation in the data available for Chile enables us also to analyze the degree to which wage differentials between individual employers are similar across occupations.The results of this study reaffirm those of previous research pointing to non-competitive explanations for wage differentials, specifically providing clear evidence that inter-firm wage premia are highly correlated across occupations.

Notizen: In the past several years, efforts have been made to introduce the 1993 System of National Accounts (1993) SNA) in most of the formerly centrally planned economies. In doing so, a number of problems have emerged, some of which are particular to the situation of these countries. Some of these problems will probably cause overestimates of national accounts variables, others will cause underestimates, and it would be purely coincidental if these effects cancel out. This paper discusses the most disconcerting issues in this situation, and possible solutions.

Notizen: The golden rule of public finance is based upon the notin that intergenerational equity requires that the cost of public expenditures be spread over time in a manner that reflects the intertemporal distribution of the benefits generated by those expenditures. This is often translated into a rule that the budget be structurally balanced in accrual accounting terms. This article considers the form of accrual accounting that is most suited to the task of measuring the consistency of fiscal policy with the golden rule. It recommends a combination of the real capital maintenance approach (also known as ‘current purchasing power accounting’) and annuity depreciation. Such an approach differs from ‘current cost accounting’, which has dominated public sector models of accrual accounting in recent years. The meaning of balance-sheet measures is also considered, and it is concluded that the golden rule is more appropriately expressed as an accrual balanced budget requirement than as a requirement for the maintenance of constant net worth. JEL classification: H6, M40.