ALBERT

Notes: A common argument advanced in the non-metropolitan counties of the US West is that the Endangered Species Act (ESA) can have, and has had, a devastating effect on local economies. However, to date, there has not been a systematic empirical analysis of the ESA's effect on local economies. This paper reports on such an analysis. Based on a sample of all 333 non-metropolitan counties in the eleven-state West, the statistical effect of the listing of threatened and endangered species on county employment growth between 1980 and 1990 is estimated. The paper's primary finding is that the hypothesis that endangered species listing has had a negative effect on the non-metropolitan county economies of the US West is not supported by the data.

Notes: This paper explores the effect of plant profitability on the closure decision in multi-locational manufacturing firms where the firm is selecting between different sites undertaking similar production activities. The paper draws upon a new interview survey of large multi-locational manufacturing firms. Analysis of the interview data shows that plant profitability is the key to understanding only one-third to one-half of selective closures and that decisions taken by subsidiaries are more likely to rely on plant profitability measures than decisions taken at the corporate head office. In analyzing a regional economy, a poor level of plant profitability is indicative of a plant at risk of closure but the absence of such a characteristic is not necessarily an indication of an assured future for a plant.

Notes: This paper explores the role of environmental factors in the contract-allocation decisions of European and North American multinational corporations (MNCs). Particular attention is given to the motivations and experiences of selected MNCs that have recently adopted environmental policies to guide specific aspects of their international purchasing procedures. The results of a pilot survey of 12 MNCs suggest that environmental issues are beginning to enter into the strategic decision-making fields of corporate planners, notably with regard to supplier selection and evaluation. The paper concludes with a brief discussion of possible directions for future empirical research.

Notes: As concern for environmental protection is growing within all sectors of society, industrial firms are being forced to become more accountable for their actions. Government policies, in the form of environmental standards, have been designed to reduce the level of toxic pollutants being discharged by firms. In order to comply with these standards, firms must either change the nature of their production processes or employ technologies that reduce the level of effluent being discharged. This paper investigates the role of environmental policy in driving firms to adopt pollution control technologies. The policy addressed is the Province of Ontario's Municipal Industrial Strategy for Abatement (MISA) which seeks to compel firms to reduce discharges of industrial effluent through the application of the “Best Available Technology Economically Achievable.” The impact of this policy instrument on the adoption of pollution control technology in the Ontario organic chemical industry is examined. The analysis is based on interviews with firms in the chemical industry which reveal that environmental policy has played a central role in inducing firms to adopt pollution control technologies. The paper draws on literature about technology diffusion, especially the relationship between suppliers and users of technology, and examines the process through which environmental technology is transferred to regulated firms. The relationship between the suppliers and users of technology is strong, especially between the large multinational users and smaller independent domestic technology suppliers.

Notes: Previous studies employing the trade area analysis procedure of pull factors assume retail sectors are independent. However, interdependencies exist between and among retail sectors. Employing a multivariate Tobit procedure, the agglomerative aspects of retail trade can be captured. Results indictate that interdependencies exist between retail sectors and if these retail interdependencies are ignored, extension and outreach retail sector programs may prove to be ineffective.

Notes: The amenity value to Kentucky residents from horse farm land was estimated using both the contingent valuation method and the hedonic pricing method. The hedonic pricing model included both the housing and labor markets. A value function estimated from dichotomous choice contingent valuation responses showed that the value of a change in the level of the horse farm amenity was sensitive to the size of the change, with no evidence of value that is independent of the size of the change. The two methods generated estimates of the external benefits from horse farm land that were within 20 percent of each other.

Notes: Although flexible specialization is regarded as one of the hallmarks of industrial districts, its consequences for firm performance have not attracted much empirical attention. Using event-history data on a complete population of textile-clothing firms in Baden-Württemberg in the Reutlingen (Germany) district from 1946 to 1993, this paper tests the proposition that specialized firms have a survival advantage over more integrated firms. Logistic regression models of failure probabilities show that, contrary to predictions derived from the district model, horizontally and vertically integrated firms have outlived more specialized firms. This study demonstrates the importance of dynamic research designs that incorporate information on strategic differences in a complete population of district firms, observed over an extended time frame.

Notes: Nuclear power plants can theoretically influence property values through a number of different channels. The public perception of risk associated with the potential hazard from the operation of a nuclear reactor and the storage of nuclear waste may lead to lower bids on properties in close proximity to the plant. In contrast, workers at the plant may be less concerned with any potential hazards, and may actually value being in proximity to the workplace. Hence, one cannot a priori sign the distance gradient of homes in the vicinity of a nuclear power plant. In this study, a hedonic model coupled with geographic information system (GIS) techniques is used to estimate housing price surfaces around two nuclear power plants in California. The use of GIS software allows more potential influences to housing prices to be accurately incorporated than previously included in hedonic studies. Based on the evidence from the plants chosen, these findings do not support the contention that negative imagery surrounding nuclear power plants or stored nuclear waste has a significant detrimental influence on residential home prices in the immediate vicinity of these facilities.

Notes: Through kinship and other links to destinations, many African American interstate migrants in the United States join other people in destination households. These “linked” migrants contrast to “independent migrants” who move as individuals or intact groups and set up their own households at the destination. Using U.S. Census Public Use Micro Sample data, this paper first shows that, in the 1985-90 period, about 45 percent of all Black interstate migrants were independent, compared to 38 percent who were linked to housing at the destination and 17 percent who moved into group quarters. Second, a multinomial logit model, incorporating individual and state-level variables, is specified that contrasts the determinants of independent and linked migration. Tests show that independent migration can be modeled with classic migration determinants, including individual educational and occupational resources, labor market conditions at the destination, and public goods at the destination including the level of welfare payments. Linked migration, on the other hand, is much less responsive to these factors, and not at all responsive to destination unemployment and welfare levels. Separate tests of male and female models suggest a great contrast between independent and linked migration for females. It is concluded that the understanding of Black migration must take into account a variety of factors beyond traditional labor market conditions, including links to the destination and individual housing circumstances.

Notes: Book Review in This Article:The Politics of Jerusalem Since 1967. By Michael Dumper.Decision Making and Spatial Behavior: A Geographic Perspective. By Reginald G. Golledge and Robert J. Stimson.Metropolitics: A Regional Agenda for Community and STability. By Myron Orfield.

Notes: . Washington DC is the center of the nation's ninth largest metropolitan area (PMSA), home to 4.4 million people and 2.9 million employees in a web of 25 separate, autonomous municipalities spanning three states and the District of Columbia. As such, the region is a good place to analyze the pattern of suburbanization of producer service employment over the past 25 years. In addition to overall suburbanization, the metropolitan area has seen changes in the nature and role of its dominant economic force, the federal government. Direct federal employment has stagnated while federal contracts to private companies have soared. Producer service employment seemed to increase in importance in jurisdictions away from the region's core, simultaneous with increases in total employment, following increases in federal contracting, and independent of increases in federal employment. These trends have affected the growth of producer service employment across the metropolitan area, encouraging their suburbanization. By subjecting our initial models to sub-sector data and analysis of temporal trends in the coefficients, we uncover the uniqueness of legal services and additional evidence of suburbanization over time.

Notes: :Differentials in U.S. state unemployment rates were persistent in the early 1990s. In addition, states with higher employment growth did not necessarily have the lowest unemployment rates. Thus, this paper examines the differentials in U.S. state unemployment rates from 1992 to 1994, decomposing them into the parts that were due to differences in recent employment growth, and those that were due to longer-term equilibrium factors. Also, using the shift-share model, employment growth differences are decomposed into an industry mix component and a competitiveness component. The decomposition of the 1992 to 1994 unemployment rate differentials is based on an econometric equation estimated using panel data from 1972 to 1991. Explanatory equilibrium factors included in the model are amenities, demographic characteristics, education, industry composition, labor mobility, and wage rates.

Notes: This paper focuses on cyclical and regional variations in vacancy dynamics in labor markets with persistent imbalances between demand and supply. In particular the so-called matching approach is used to investigate labor market efficiency across regions and over the business cycle. In this matching approach the relationship between the flow of filled vacancies and regional stocks of unemployed job seekers and vacant jobs is specified in a “search production” function. The matching approach is applied to the Dutch labor market, which is characterized by strong disequilibria and persistent regional differences in unemployment and vacancy rates. To explore the development of these regional imbalances from a demand side perspective, the dynamic structure of regional data on vacancies is analyzed over the business cycle. The movements of vacancy duration and the change in the vacancy stock over time appear to be similar across Dutch regions. Moreover, an investigation of the structural causes of regional variations in vacancy duration via shift-share analysis makes clear that regional differences in sectoral composition of unfilled vacancies do not contribute to regional differences in vacancy duration in the period 1989–93. Estimation results of a matching model reveal that there are no region-specific differences in labor market efficiency to produce filled vacancies. The ratio of vacancies to unemployment appears to be the critical determinant of the matching process in the Dutch regions. Another general (non region-specific) finding is that the estimated labor market efficiency increases during recessionary and recovery periods while it decreases during an economic boom.

Notes: This paper evaluates the influence of residential density on commuting behavior across U.S. cities while controlling for available opportunities, the technology of transportation infrastructure, and individual socio-economic and demographic characteristics. The measures of metropolitan and local density are addressed separately. It is suggested that metropolitan residential density serves principally as a surrogate for city size. Markets react to high interaction costs found in large cities by raising density rather than density being a cause of those high costs. Local residential density measures relative location (accessibility) within the metropolitan region as well as indexing the level of congestion. Regressions are conducted to predict commuting time, speed, and distance, by mode of travel on a cross-section of individuals nationally and city by city. The results indicate that residential density in the area around the tripmaker's home is an important factor: the higher the density the lower the speed and the shorter the distance. However, density's effect on travel time is ambiguous; speed and distance are offsetting effects on time. The paper suggests a threshold density at which the decrease in distance is overtaken by the congestion effects, resulting in a residential density between 7,500 and 10,000 persons per square mile (neither the highest nor lowest) with the shortest duration auto commutes.

Notes: Book reviews in this article:The Urban Order: An Introduction to Cities, Culture, and Power. By John Rennie Short.Work-Place: the Social Regulation of Labor Markets. By Jamie Peck.Privatization, Conversion, and Enterprise Reform in Russia. By Michael McFaul and Tova Perlmutter.Mastering Space: Hegemony, Territory and International Political Economy. By John Agnew and Stuart Corbridge.Rising in the East: the Regeneration of East London. Edited by Tim Butler and Michael Rustin.

Notes: Among the environmental issues that have come to dominate social concerns, the amount of packaging sent for disposal in landfills has gained increased prominence in Canada, with the issuance in 1990 of the National Protocol on Packaging (NAPP). Recognizing the increased demands for improved environmental performance on the part of corporations, this study seeks to understand why some companies respond more quickly than others to concerns about packaging-waste reduction. The paper links concepts found in the Corporate Social Responsibility and Innovation Theory literatures, in order to explore corporate response patterns to pressures for change and to develop a measure of corporate performance with regards to packaging-waste reduction efforts. Bivariate and linear logit analyses of data were undertaken, and confirm that variations in a company's response pattern can be explained in terms of factors such as company size, product orientation, and existence of an environmental affairs function, as well as external policies, such as NAPP.

Notes: Book Review in this Aricle:Transportation Planningon Trial: The Clean Air Actand Travel Forecasting. By Mark Garrett and Martin Wachs.Interstate Relations: The Neglected Dimensionof Federalism. By Joseph F. Zimmerman.Improving Poor People. By Michael B. Katz.Logics of Dislocation: Models, Metaphors, and Meanings of Economic Space. By Trevor J. Barnes.Estimating Economic Values for Nature. By V. Kerry Smith.

Notes: This paper considers the behavior of actors in real estate markets in the face of environmental uncertainty. Environmental legislation has increased in scale and scope with obvious implications for property markets. Developers, investors, occupiers, and lenders may all be affected by changing environmental standards. Any factor that creates valuation uncertainty will have major impacts. Blighted sites and properties will be shunned, while existing real estate portfolios will be adversely affected. A survey of UK property practitioners on their attitudes to environmental hazard reveals that firms seem pessimistic as to their ability to quantify and model the economic and investment implications of environmental risk. There are concerns here for the wider economy and for the business community through supply-side constraints and suboptimal location. There are implications, too, for local and regional regeneration strategies as whole areas may be blighted by potential contamination. There may be mispricing and arbitrage opportunities in relation to such assets that can be exploited through first mover advantage by firms willing and able to develop effective risk-sensitive appraisal models.

Notes: The traditional shift-share model measures the combined effects of output growth and productivity change on employment. A region with above average employment growth either has a favorable industry mix or enjoys a competitive advantage over other regions. To separate the effects of output and productivity, the shift-share model is extended to decompose the effects of changes in output and productivity on employment. This paper modifies the Rigby-Anderson extension by separating the contribution of labor and capital to productivity growth in the analysis of regional economic performance, and investigates twenty (two-digit SIC) manufacturing sectors in twelve states (six snowbelt, six sunbelt states) to assess whether observed changes in employment were due to changes in output or to productivity.

Notes: This paper explores the extension of integrated econometric/input-output models from a single to a multiregional context. A number of methodological issues associated with existing treatments of extraregional relations in both traditional multiregional econometric models and the more recent single region integrated models are discussed. A series of new approaches are introduced that rely on the integration of econometric and input-output methods to specify extraregional linkages. A comparison of these alternative modeling approaches is undertaken using employment series for 5 regions in Southern California. The forecasting accuracies are evaluated in a series of out-of-sample forecasting experiments. The findings suggest that the forecasting performance of the multiregional extensions of the integrated approach is competitive with the performance of single region implementations. The performance of the alternative multiregional approaches is found to be relatively more sensitive to regionalization of the IO component and the level of industrial disaggregation than to the incorporation of distance in the specification of the multiregional linkages.

Notes: Given the dramatic divergence of postwar performance across the developing world despite almost half a century of accumulated technical expertise in the advice offered by the academic and donor communities, it has become increasingly clear that a study of differential development patterns over time requires an analysis of not only what happened but also why it happened. This paper seeks to bridge this gap by attempting to endogenize policy choice in different developing country settings in order to elucidate why similar policy advice is so often differently received. It is my basic premise that a country's initial conditions—its natural resource endowment, organic nationalism, and ability to attract foreign capital—explain why some LDCs pursue a relatively linear path toward “modem-growth” organizational characteristics, while others exhibit policy oscillations en route. A theoretical framework is developed to trace such causal relationships as they play themselves out in a political economy context over time. The policy responses to external shocks of Mexico, the Philippines and Taiwan, three countries differing in terms of various dimensions of their initial conditions, are then examined, along with their consequent performance over the past thirty years in order to empirically test the hypotheses laid out in the framework.

Notes: This paper examines the role of internal and external research, design and development (RD&D) activity in the innovation performance of New York State manufacturing firms in the scientific instruments sector. Survey data from a sample of 204 small and medium-sized companies suggest that the incidence of successful product development is higher among firms that combine in-house RD&D with technical support from independent specialists. Significantly, firms that supplement their in-house innovation efforts with outside talent are found to exhibit better commercial performance than their counterparts that operate on the basis of either internal or external technical resources alone. The paper concludes with a brief agenda for future empirical research on the conditions that support product innovation among small and medium-sized firms.

Notes: The Geography of Finance: Spatial Dimensions of Intermediary Behaviour. By David J. Porteous. (ed)Plowing the Sea: Nurturing the Hidden Sources of Growth in the Developing World. By Michael Fairbanks and Stace Lindsay.

Notes: A major controversy during the debate over the North American Free Trade Agreement focused on the impact of NAFTA on Mexico's environment. This paper examines the evidence of impact specifically on Mexico's environmental policy. Criteria of impact are developed, and comparisons made for three periods: before 1990 as the baseline period; 1990-93 when NAFTA was being negotiated; and beginning in 1994 when NAFTA came into effect. Much evidence indicates that Mexico's environmental policymaking and enforcement did improve in the early 1990s while NAFTA was being debated. Some evidence also suggests that the NAFTA-influenced environmental commitment was sustained during the 1995 financial crisis. Thus, it is concluded that NAFTA has contributed significantly to Mexico's environmental policy.

Notes: This paper develops a model of the relationship between the solid waste recycling activities of industrial-commercial-institutional (ICI) firms and two sets of explanatory variables: characteristics of the firm and characteristics of the waste materials. The model is tested for six types of waste material (paper, paperboard, plastic, glass, wood, and metal) using logistic regression analysis and drawing on waste quantity and composition data collected from a sample of over 400 ICI firms in metropolitan Toronto. The percentage of firms recycling materials ranged from a high of 46 percent for paperboard to a low of 8 percent for plastics. In all of the models tested, quantity of waste material produced was found to be a significant explanatory variable in determining whether a firm will recycle that material. Other variables which were found to be significant in explaining recycling of some, but not all, material types were floor space of the firm, and type of economic activity. Despite theoretical support for its inclusion, employment was not found to be significant in any of the models.

Notes: Abstract. Methane (CH4) is an important greenhouse gas. Flooded rice fields (paddies) are a significant source of atmospheric CH4; estimates of the annual emission from paddies range from less than 20 to 100 million Tg, with best estimates of 50 × 20 Tg. The emission is the net result of opposing bacterial processes: production in anaerobic microenvironments, and consumption and oxidation in aerobic microenvironments, both of which occur sequentially and concurrently in flooded rice soils. With current technologies, CH4 emission from rice fields will increase as production increases. Over the next 25 years rice production will have to increase by 65% from the present 460 Mt/y to 760 Mt/y in 2020. The current understanding of the processes controlling CH4 fluxes, rice growth and rice production is sufficient to develop mitigation technologies. Promising candidates are changes in water management, rice cultivars, fertilization, and cultural practices. A significant reduction of CH4 emission from rice fields, at the same time that rice production and productivity increase at the farm level, is feasible, although the regions where particular practices can be applied, and the trade-offs that are possible, have still to be identified.

Notes: Abstract. Increases in the emissions of globally important nitrogen (N) oxide gases have coincided with significant changes in land use in the tropics. Clearing of tropical forests and savannas for agriculture currently represents the most extensive alteration of land cover on the planet. Over the last several decades, N fertilizer use has increased globally, and in China and the developing world, use has recently surpassed that in the developed world. The potential contribution of land-use change in the tropics to the increase in N oxides is great, yet only a few studies have measured N oxide emissions after tropical land conversion. Our summary of available research shows some conversions to pastures and a few management practices, especially those using N fertilizers, increase emissions beyond those found in undisturbed ecosystems. However, not all studies show unequivocal increases in emissions. Accordingly, we call for a mechanistic understanding of the processes controlling trace gas fluxes to adequately predict under what conditions increased emissions may occur. More measurements are needed to build and test models that may improve management of N fertilizer use in tropical agricultural systems. Given the expected expansion of agriculture and increased use of N fertilizers in the tropics, increased emissions of N oxides from the tropics are likely.

Notes: Abstract. Grazing animals on managed pastures and rangelands have been identified recently as significant contributors to the global N2O budget. This paper summarizes relevant literature data on N2O emissions from dung, urine and grazed grassland, and provides an estimate of the contribution of grazing animals to the global N2O budget.The effects of grazing animals on N2O emission are brought about by the concentration of herbage N in urine and dung patches, and by the compaction of the soil due to treading and trampling. The limited amount of experimental data indicates that 0.1 to 0.7% of the N in dung and 0.1 to 3.8% of the N in urine is emitted to the atmosphere as N2O. There are no pertinent data about the effects of compaction by treading cattle on N2O emission yet. Integral effects of grazing animals have been obtained by comparing grazed pastures with mown-only grassland. Grazing derived emissions, expressed as per cent of the amount of N excreted by grazing animals in dung and urine, range from 0.2 to 9.9%, with an overall mean of 2%. Using this emission factor and data statistics from FAO for numbers of animals, the global contribution of grazing animals was estimated at 1.55 Tg N2O-N per year. This is slightly more than 10% of the global budget.

Notes: Abstract. Agricultural soils, having been depleted of much of their native carbon stocks, have a significant CO2 sink capacity. Global estimates of this sink capacity are in the order of 20-30 Pg C over the next 50-100 years. Management practices to build up soil C must increase the input of organic matter to soil and/or decrease soil organic matter decomposition rates. The most appropriate management practices to increase soil C vary regionally, dependent on both environmental and socioeconomic factors.In temperate regions, key strategies involve increasing cropping frequency and reducing bare fallow, increasing the use of perennial forages (including N-fixing species) in crop rotations, retaining crop residues and reducing or eliminating tillage (i.e. no-till). In North America and Europe, conversion of marginal arable land to permanent perennial vegetation, to protect fragile soils and landscapes and/or reduce agricultural surpluses, provides additional opportunities for C sequestration.In the tropics, increasing C inputs to soil through improving the fertility and productivity of cropland and pastures is essential. In extensive systems with vegetated fallow periods (e.g. shifting cultivation), planted fallows and cover crops can increase C levels over the cropping cycle. Use of no-till, green manures and agroforestry are other beneficial practices. Overall, improving the productivity and sustainability of existing agricultural lands is crucial to help reduce the rate of new land clearing, from which large amounts of CO2 from biomass and soil are emitted to the atmosphere.Some regional analyses of soil C sequestration and sequestration potential have been performed, mainly for temperate industrialized countries. More are needed, especially for the tropics, to capture region-specific interactions between climate, soil and management resources that are lost in global level assessments.By itself, C sequestration in agricultural soils can make only modest contributions (e.g. 3-6% of total fossil C emissions) to mitigating greenhouse gas emissions. However, effective mitigation policies will not be based on any single ‘magic bullet’ solutions, but rather on many modest reductions which are economically efficient and which confer additional benefits to society. In this context, soil C sequestration is a significant mitigation option. Additional advantages of pursuing strategies to increase soil C are the added benefits of improved soil quality for improving agricultural productivity and sustainability.

Notes: Abstract. The validity of the model described in Greenwood & Karpinets (1997) was tested against the results of single year, multi level K fertilizer experiments. Measurements of plant mass, %K in the plant and K activity ratio in soil had been made at harvest and at intervals during the growing season on spring wheat, summer cabbage and turnips. Reasonably good agreement was obtained between these measurements and simulated values when the two ‘crop’ parameters (defining the dependence of critical and maximum possible %K on plant mass) were adjusted for each crop. Also good agreement was generally obtained for plant weight and plant %K at harvest in less detailed experiments on 10 other crops. Values of the two ‘crop’ parameters for 12 of the crops were strongly correlated with one another suggesting that a single ‘crop’ parameter may be all that is required to define most inter-species differences in plant-K demand.Simulations with the model indicate that, in central England, no response of 10 crops to K fertilizer would be likely on soils containing more than 170 mg of 1 M ammonium nitrate extractable-K/kg of soil and having clay contents of between 15 and 45%. Shortcomings of the model and opportunities for advance are discussed.A simplified version of the model runs on the Internet at:

Notes: Abstract. The effect of rate and timing of autumn/winter straw incorporation on the immobilization of spring-applied N-fertilizer are studied. The immobilization of 15N-labelled fertilizer by straw was determined in pot trials with a sandy loam soil (Wick series) collected from two field experiments. In experiment 1, straw was incorporated at four different rates in the autumn; experiment 2 had a fixed rate of straw (7.5 t/ha) incorporated at monthly intervals from September to March. Immobilization in spring was not enhanced when only stubble was incorporated in autumn. However, autumn incorporation of 7.5 t/ha straw resulted in a significant increase in the immobilization of spring-applied N, equivalent to 10 kg/ha; when 15 t/ha straw was incorporated, immobilization increased to 18 kg/ha. The enhancement of immobilization, immediately following fertilizer application, was dependent on the extent of straw decomposition prior to N application. Thus immobilization was related to cumulative thermal time (day °C above 0°C; Tsum between the date of straw incorporation and fertilizer application). Straw which had been incorporated for Tsum 〉 1200 no longer caused appreciable immobilization of spring fertilizer.

Notes: Book reviewed in this article: Erosion and sediment yield: global and regional perspectives Edited by D. E. Walling and B. W. Webb.

Notes: Abstract. The restorative ability of herbaceous (Psophocarpus palustris, Pueraria phaseoloides) and woody (Leucaena leucocephala, Senna siamea, Acacia leptocarpa, Acacia auriculiformis) legume species and of natural regrowth was studied on an eroded and compacted Oxic Paleustalf in southwestern Nigeria. Compared to the control treatment that was continuously cropped for 15 years, four years of fallowing significantly improved test crop yields. However, fallowing with the above species did not substantially improve soil properties, particularly soil bulk density. A longer fallow period may be needed to amend soil physical conditions of this degraded Alfisol. Soil chemical properties were greatly improved following land clearing and plant biomass burning in 1993. However, the residual effect of burning on soil fertility was insignificant in the second cropping year. Among the fallow species, P. palustris and natural fallow showed the best residual effect on test crop performance. Despite the high biomass and nutrient yields of S. siamea and A. auriculiformis, test crop yields on these plots were low due to the border effects from the uncleared and fallowed subplots.

Notes: Abstract. To study the influence of different vegetation species and plant properties on the generation of surface runoff and soil erosion in south east Spain, a series of rainfall simulation experiments was conducted on small (c. 1.5 m2) plots. These were carried out in October 1993 and May 1994 on two sites close to Murcia. Six vegetation types were studied, with some at different stages of maturity, giving a total of nine vegetation treatments and two bare soil treatments. Four replicates of each treatment were exposed to a rainstorm of 120 mm/h for 15 minutes. The results of the experiments show that there are few significant differences in the ability of the vegetation types studied to control runoff or soil erosion. Of the plant properties considered, only plant canopy cover showed a significant relationship with soil loss and runoff with the greatest reduction in soil loss taking place at canopy covers greater than 30%. The implications of this research are that future efforts should be directed at developing ecological successions and revegetation methods which promote a substantial and sustainable canopy cover.

Notes: Abstract. This paper reports results from a four year study to investigate the suitability of porous ceramic cups to measure solute leaching on shallow chalk soils. Measurements were carried out in one field following surface applications of nitrate and bromide tracers and in two fields after only bromide was applied. Soil water samples were collected from porous cups at 30,60 and 90cm depth after every 25 mm of drainage, and soil samples from 0–30, 30–60 and 60–90 cm were collected monthly eachwinter. Soil matric suctions andvolumetric moisture content were measured in one winter. Leaching losses, measured with ceramic cups were compared with those measured by soil analysis. Porous cups installed in chalk at 60 and 90 cm depth were only able to collect samples regularly when soil matric suctions were less than 15 kPa. Water held at such low suctions is likely to move quickly through relatively large fissures in the chalk. The slow rate of equilibration between solute concentrations in water moving in macrofissures and those in water moving through micropores of the chalk matrix, means that porous cups may not provide good estimates of leaching losses if they are installed in chalk rock.

Notes: By both effect and example, tax policy in the United States has a huge impact on the rest of the world. This paper explores five features of the American tax system that seem, from a British and European perspective, to be both especially peculiar and potentially instructive. These are: the remarkably low overall level of taxation; the absence of a value added tax (or any other general national tax on consumption); the absence of any explicit interstate equalisation; the marginal subsidisation of low earnings under the Earned Income Tax Credit; and the fragmentation of power in policymaking, an important aspect of which is the role played by the Constitution. JEL classification: H10, H20, H50, H70.

Notes: In this paper, we investigate pay structures in the private and public sectors for West Germany. We commence by describing some basic features of the public sector. We use micro-data from the German Socio-Economic Panel for the years 1984–93 to analyse developments and differences in public and private sector wage distributions for both males and females. We break wages down into different education groups and age-groups, and use regressions to construct conditional wage differentials. Our results differ in many aspects from findings for the UK. For instance, we find that although mean wages are higher in the public sector for both males and females, conditional wages are higher in the private sector for all education groups for males, but higher in the public sector for females. JEL classification: J3.

Notes: This article, acknowledging the potentially important general attractions of the allowance for corporate equity (ACE), looks at some of its more specific implications.On corporate taxes, the article looks at questions about the implied revenue-neutral rate of corporation tax (and redistribution of the tax burden); the effects on cash flow of both government and companies; and what would become a crucially important charge on capital gains.On income tax, the article comments on the implications for self-employed earnings (and also, potentially, employees); for investment income and the logically accompanying EXPEP (extended personal equity plan); and therefore for inheritance tax.For international investment, the article notes that unless and until other countries adopt an ACE as the basis for harmonisation, the interaction of the ACE and existing taxes would not always be helpful for outward investment; and on some inward investment, if the most optimistic assumptions are not borne out, the effects could be rather bleak. JEL classification: H25, K34.

Notes: After a period of consultation, it has been decided that the Revenue should be empowered to issue legally-binding rulings in favour of taxpayers only where the relevant transaction has already taken place. This paper considers the reasons for having binding rulings, and argues that those reasons justify implementing pre- as well as post-transaction rulings. Additionally, it is contended that many of the more detailed aspects of the proposal warrant reconsideration in light of those underlying rationales. JEL classification: H20, K34.

Notes: This paper explores the implications of examining the effect of policy changes on individual incomes rather than household incomes. Conceptual problems arise from the treatment of collective resources and responsibilities, particularly children. These are dealt with in a manner that is transparent with the aim of establishing a practical method of analysing policy at the individual (and gender-specific) level. Two policy-related issues are examined in this framework: the impact of a minimum wage and the effect of introducing a minimum pension guarantee. In each case, the implications of choosing the individual as the income unit are examined and analysis of the issue by gender is presented. JEL classification: C81, D31, H55, J16.

Notes: Abstract. The effect of superficial liming of acidic forest soils on CO2 and N2O emissions and CH4 uptake was investigated with closed chambers in two deciduous and two spruce forests, by weekly to biweekly measurements over at least one year. The flux rates of untreated areas varied between 1.94 and 4.38 t CO2-C/ha per y, 0.28 and 2.15 kg/N2O-N/ha per y and between 0.15 and 1.06 kg CH4-C/ha per y. Liming had no clear effect on CO2 emissions which may change in the long-term with decreasing root turnover and increasing C-mineralization. Apart from one exception, liming resulted in a reduction of N2O emissions by 9 to 62% and in an increase of CH4 uptake by 26 to 580%. The variability in N2O emissions between the forest sites could not be explained. In contrast, the variability of annual CH4 uptake rates could be explained by N content (r2= 0.82), C content (r2= 0.77), bulk density (r2= 60), pore space (r2= 0.59) and pH (r2= 0.40) of mineral soil at a depth of 0 to 10 cm, and by the quantity of material in the organic layer (r2= 0.66). Experiments with undisturbed columns of the same soils showed that between 1 and 73% of the total N2O emissions came from the organic layer. However, atmospheric CH4 was not oxidized in this layer, which represents a diffusion barrier for atmospheric CH4. When this barrier was removed, CH4 uptake by the mineral soil increased by 25 to 171%. These results suggest that liming of acidic forest soils causes a reduction of the greenhouse gases N2O and CH4 in the atmosphere, due to changes in the chemical, biological, and physical condition of the soils.

Notes: Abstract. Increases in the atmospheric concentrations of nitrous oxide (N2O) contribute to global warming and to ozone depletion in the stratosphere. Nitric oxide (NO) is a cause of acid rain and tropospheric ozone. The use of N fertilizers in agriculture has direct and indirect effects on the emissions of both these gases, which are the result of microbial nitrification and denitrification in the soil, and which are controlled principally by soil water and mineral N contents, temperature and labile organic matter.The global emission of N2O from cultivated land is now estimated at 3.5 TgN annually, of which 1.5 Tg has been directly attributed to synthetic N fertilizers, out of a total quantity applied in 1990 of about 77Tg N. This amount was 150% above the 1970 figure. The total fertilizer-induced emissions of NO are somewhere in the range 0.5-5 Tg N. Mineral N fertilizers can also be indirect as well as direct sources of N2O and NO emissions, via deposition of volatilized NH3 on natural ecosystems and denitrification of leached nitrate in subsoils, waters and sediments.IPCC currently assume an N2O emission factor of 1.25 ± 1.0% of fertilizer N applied. No allowance is made for different fertilizer types, on the basis that soil management and cropping systems, and unpredictable rainfall inputs, are more important variables. However, recent results show substantial reductions in emissions from grassland by matching fertilizer type to environmental conditions, and in arable systems by using controlled release fertilizers and nitrification inhibitors. Also, better timing and placement of N, application of the minimum amount of N to achieve satisfactory yield, and optimization of soil physical conditions, particularly avoidance of excessive wetness and compaction, would be expected to reduce the average emission factor for N2O. Some of these adjustments would also reduce NO emissions. However, increasing global fertilizer use is likely to cause an upward trend in total emissions even if these mitigating practices become widely adopted.

Notes: Abstract. Field measurement of landfill methane (CH4) emissions indicates natural variability spanning more than seven orders of magnitude, from less than 0.0004 to more than 4000 g/m2 per day. This wide range reflects net emissions resulting from production (methanogenesis), consumption (methanotrophic oxidation), and gaseous transport processes. The determination of an ‘average’ emission rate for a given field site requires sampling designs and statistical techniques which consider spatial and temporal variability. Moreover, particularly at sites with pumped gas recovery systems, it is possible for methanotrophic microorganisms in aerated cover soils to oxidize all of the CH4 from landfill sources below and, additionally, to oxidize CH4 diffusing into cover soils from atmospheric sources above. In such cases, a reversed soil gas concentration gradient is observed in shallow cover soils, indicating bidirectional diffusional transport to the depth of optimum CH4 oxidation. Rates of landfill CH4 oxidation from field and laboratory incubation studies range up to 166 g/m2 per day, among the highest for any natural setting, providing an effective natural control on net emissions. It has been shown that methanotrophs in landfill soils can adapt rapidly to elevated CH4 concentrations with increased rates of CH4 oxidation related to depth of oxygen penetration, soil moisture, and the nutrient status of the soil.Estimates of worldwide landfill CH4 emissions to the atmosphere have ranged from 9 to 70 Tg/y, differing mainly in assumed CH4 yields from estimated quantities of landfilled refuse. At highly controlled landfill sites in developed countries, landfill CH4 is often collected via vertical wells or horizontal collectors. Recovery of landfill CH4 through engineered systems can provide both environmental and energy benefits by mitigating subsurface migration, reducing surface emissions, and providing an alternative energy resource for industrial boiler use, on-site electrical generation, or upgrading to a substitute natural gas. Manipulation of landfill cover soils to maximize their oxidation potential could provide a complementary strategy for controlling CH4 emissions, particularly at older sites where the CH4 concentration in landfill gas is too low for energy recovery or flaring. For the future, it is necessary to better quantify net emissions relative to rates of CH4 production, oxidation, and transport. Field measurements, manipulative studies, and model development are currently underway at various spatial scales in several countries

Notes: Book Reviewed in this article: Phosphorus loss from soil to water: Edited by H. Tunney, O. T. Carton, P. C.

Notes: Abstract. Variously timed sub-optimal irrigation strategies were applied to sugarbeet grown on a light soil (loamy sand or sandy loam) over four seasons (1991 to 1994) to investigate the effect on crop growth and nitrate leaching risk. Data from the two dry seasons, (1991 and 1994) are reported here. In the driest year (1991) soil mineral N levels after autumn harvest were negatively related to crop water use (P 〈 0.05). In this season, there was little drainage from the soil profile, and full irrigation reduced residual soil N by 31 kg N/ha (0-90 cm) compared with the unirrigated treatment (79 kg N/ha). The potential for N leaching during the ensuing winter was consequently more than halved. In 1991 and 1994 there was a strong positive linear relationship between dry matter yield, N uptake and water use, but a negative relationship between plant N concentration and water use. These relationships were a function of the severity and not the timing of drought. The additional N uptake associated with increased irrigation and crop water use was biased towards a large concentration in the aboveground crop (tops), which are normally returned to the soil. The C:N ratio of sugarbeet tops was affected by crop water supply with droughted crops having lower values. This would also influence N release and subsequent leaching risk. However, the effects of drought on N leaching risk were relatively small when compared with other root crops such as potatoes.

Notes: Abstract. To provide a practical aid to improving fertilizer practice a mechanistic model was developed that can be readily calibrated for widely different crops. Most of the inputs are easy to obtain and the others, the amounts of fixed soil-K and the velocity constants for fixation and release of soil-K, can be readily measured by a novel procedure which is described.The model calculates for each day the potential increase in plant weight and the increment in root length, from the current plant mass, its %K and pan evaporation. It calculates the maximum amount of K that could be transported through soil to the root surfaces. It modifies this potential uptake by taking account of the ‘feedback’ of plant K on root absorption to give the actual uptake and a new %K in the plant. It calculates the radii of the depletion zones around each root increment and the interchange between the solution, exchangeable and fixed-K in these zones and also in the undepleted regions of soil. Routines are included for the effects of weather on the various processes. Differences between species are accommodated by selecting one of three algorithms for root growth and by adjusting the values of two crop-K parameters that define the decline in a critical and a maximum possible %K with increase in plant mass per unit area.A simplified version of the model runs interactively on the Internet at:

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

Notes: Book Reviewed in this article: Freshwater Contamination By B. Webb (editor).

Notes: Book Reviewed in this article: Biotechnical and soil bioengineering slope stabilization. A practical guide for erosion control By D. H. Gray & R. B. Sotir.

Notes: Abstract. An effective fertilizer recommendation system requires information on seasonal, soil-related and cultural variations in soil mineral nitrogen (N) and nutrient requirements of the crop. This can be provided by dynamic N turnover models, such as listed by Plentinger & Penning De Vries (1996). In this paper, we describe a survey of farmer opinion designed to ascertain what farmers want from such a decision support system. Over 100 farmers were surveyed. Surveyed farmers requested that default values be available for all model inputs. Inputs should be entered both by windows-based menu (for clarity) and tabular format (for speed), have user-selected units, and be fully supported by context-sensitive help. The system should have a hierarchical structure allowing access to fixed parameters, and be compatible with commonly used farm recording packages. Recommendations should be provided both for the field (single and optional application rates), and in tabular format across the whole farm. Simulations should be easily rerun using more recent crop and weather data. Turnover processes underlying recommendations should be illustrated by flow diagrams of flux between pools, pie charts of fertilizer fate, bar charts of movement down the soil profile and graphical plots of changes in N status against time.

Notes: Abstract. Field experiments undertaken at 14 sites, on a range of soil types, in lowland England, during the cropping years 1989–1993, tested the effectiveness of cattle or pig slurry as a source of nitrogen for cereal cropping. Slurry was applied in autumn, winter and spring, to autumn and spring sown cereal crops. Assessments included slurry nitrogen efficiency relative to N in spring applied fertilizer in terms of both grain yield and grain protein production, apparent crop recovery and content of mineral nitrogen in soil profiles. Crop response to nitrogen was poor at seven sites where high residues of soil mineral nitrogen (SMN) were present. On the seven responsive sites, spring slurry applications proved more efficient (mean 40%) as a source of N than autumn (mean 24%) or winter applications (mean 32%). These differences were smaller than reported in a number of other studies, probably as a result of relatively low excess winter rainfall, resulting in less nitrate leaching during the period of the investigation. Rapid incorporation into the topsoil of slurry applied in autumn, increased (28 kgN/ha) the SMN of samples taken early in the winter. However this increase did not lead to a consistent improvement in crop N uptake. Slurry dressings, whenever applied, can be expected to make a significant contribution to the N requirement of the succeeding crop and need to be taken into account when calculating the appropriate spring fertilizer application.

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

Notes: Abstract. Ceramic suction cups were used to obtain samples of soil solution from permanently grazed swards receiving 200 kg N/ha/y. The suction cups were installed in 1 ha plots at 10, 30 and 60 an depth in a poorly drained, heavy clay soil in S. W. England. The plots were hydrologically isolated from each other by perimeter drains which channelled surface runoff water into v-notch weirs. In one treatment, artificial drainage by a system of field and mole drains also converged to outfalls through v-notch weirs, which enabled samples to be taken. Nitrate and a range of other ionic constituents were examined over a 12 month period in soil solutions taken from the suction cups and compared with leachate obtained from the field drains and surface channels. Field drain samples frequently exceeded the EC limit of 11.3 mg nitrate-N/1, but concentrations in suction cups obtained during the same period did not, and were up to ten-fold less. Although correlations for ions were found between different sampling depths and drainage samples, no clear patterns emerged. It was concluded that suction cups were inappropriate for the determination of the overall leaching losses in this soil type, but provided useful data on changes in ionic concentrations which occurred in different soil horizons through to drainage outfalls.

Notes: A standardized dataset of derived soil properties for the 106 soil units considered on FAO-UNESCO's 1:5 million scale Soil Map of the World is presented. It was derived from a statistical analysis of the 4353 soil profiles held in the WISE (World Inventory of Soil Emission) database, which was developed at the International Soil Reference and Information Centre (ISRIC) for the geographic quantification of soil factors that control processes of global change. Median values are presented by soil unit for selected soil properties including: pH(H2O); organic carbon content; cation exchange capacity; sum of exchangeable Ca2+, Mg2+ and K+; exchangeable sodium percentage; bulk density; total porosity; available water capacity; soil drainage class; and gravel content class. Medians for these variables are presented both for the topsoil (0–30 cm) and subsoil (30–100 cm), where applicable. The data set can help to refine ratings for soil quality in global environmental models pending the availability of comprehensive georeferenced databases on soil and terrain resources such as SOTER, the World Soil and Terrain Database. In a Geographical Information System (GIS) it can be linked to the units shown on the digital Soil Map of the World through the legend code.

Notes: Abstract. The effect of grazing pressure on infiltration, runoff, and soil loss was studied on a natural pasture during the rainy season of 1995 in the Ethiopian highlands. The study was conducted at two sites with 0–4% and 4–8% slopes at the International Livestock Research Institute (ILRI) Debre Zeit research station, 50 km south of Addis Ababa. The grazing regimes were: light grazing stocked at 0.6 animal-unit-months (AUM)/ha; moderate grazing stocked at 1.8 AUM/ha; heavy grazing stocked at 3.0 AUM/ha; very heavy grazing stocked at 4.2 AUM/ha; very heavy grazing on ploughed soil stocked at 4.2 AUM/ha; and a control with no grazing. Heavy to very heavy grazing pressure significantly reduced biomass amounts, ground vegetative cover, increased surface runoff and soil loss, and reduced infiltrability of the soil. Reduction in infiltration rates was greater on soils which had been ploughed and exposed to very heavy trampling. It was observed that, for the same % vegetative cover, more soil loss occurred from plots on steep than gentle slopes, and that gentle slopes could withstand more grazing pressure without seriously affecting the ground biomass regeneration compared to steeper slopes. Thus, there is a need for developing ‘slope-specific’ grazing management schedules particularly in the highland ecozones rather than making blanket recommendations for all slopes. More research is needed to quantify annual biophysical changes in order to assess cumulative long-term effects of grazing and trampling on vegetation, soil, and hydrology of grazing lands. Modelling such effects is essential for land use planning in this fragile highland environment.

Notes: Abstract. Use of either three or six occasions to spread similar total amounts of slurry was investigated over the late winter/early spring period in two years, on plots with underdrainage. Slurry was spread on four 7 m by 25 m plots which were instrumented to allow collection of drainflow and runoff. The ‘mobile water’ pore space allowed transport of a small proportion of applied slurry through the 0.75 m soil profile. Evidence of a polluted ‘mobile water’ pulse occurred after periods of up to 48 hours following spreading, suggesting subsurface rather than overland flow. Timing of the pulse depended on whether subsequent rainfall accelerated the flow The contaminated flow persisted for 6–12 hours. The worst contamination of 39 mg/l NH4+ -N occurred under ‘bypass flow’ conditions, when 52 mm of rain fell during the 48 hours after a 5.2 mm application. Two contributory factors appeared important. The first was the long duration of the high intensity storm and the second was an extended period of severe frost believed to have created fissures associated with frost heave. Making several applications of slurry in amounts less than 35 m3/ha is preferable to fewer larger applications during spring, for cereals on medium to heavy soils. This recognises the likelihood of there being underdrainage on arable land and the optimal use of well-drained, partially frozen ground to avoid compaction by slurry tankers.

Notes: This paper examines elements of British tax policy and discusses their implications for the US, where several recent proposals would mirror aspects of the British system. These include reducing filing requirements under the individual income tax, indexing capital gains for inflation, cutting mortgage interest deductions, enacting a value added tax, and integrating the corporate and personal income taxes. The paper also discusses implications of the poll tax for tax reform. Britain and America have made different choices involving equity, efficiency, simplicity and other goals. These choices offer the chance to help identify the impact of tax policy. JEL classification: H20.

Notes: This paper examines the relationship between the cross-sectional and lifetime income distributions using a simple model of relative income mobility. It asks whether cross-sectional comparisons between countries can provide a good indication of lifetime inequality differences if income mobility is similar, and whether lifetime inequality increases by less than cross-sectional inequality if the latter increases as a result of higher mobility. Analytical and simulation methods are used to show that the answer to both questions is negative. Comparisons must allow for different types of mobility, the nature of the age-income profile and the age distribution in each country. JEL classification: D31.

Notes: There is an unresolved debate on the effect of tax-based savings incentives on government revenue. The conventional wisdom on tax-assisted saving plans (TASPs) holds that they reduce public savings, but may raise national savings by stimulating private savings. Feldstein (1995) has challenged the view that TASPs reduce government revenue. According to Feldstein, ‘some of the increase in personal saving raises the corporate capital stock, and the return on this additional capital raises corporate tax payments’. When the additional corporate income tax revenue is taken into account, ‘the revenue loss associated with IRAs [Individual Retirement Accounts] either is much smaller than has generally been estimated or is actually a revenue gain’.This paper extends Feldstein's analysis to incorporate international considerations, differences in tax structures and alternative values for key parameters. We show that the result presented by Feldstein represents a special case that does not lead to broad generalisations. We also show that, under most conditions, the tenets of conventional wisdom that TASPs reduce government revenue are likely to hold, but that the magnitude of the effect may not be large. Finally, we suggest that the focus of research on the savings effects of TASPs is justifiable in a closed economy, where domestic savings affect domestic investment, but is not useful for policy development in small open economies. JEL classification: H2, H3, H6.

Notes: The possibility of an earned income tax credit, based on the US model, is currently high up the British political agenda. This paper examines the strengths and weaknesses of the current British system of in-work benefits, before reviewing the effectiveness of the US Earned Income Tax Credit (EITC) scheme. The British and US systems are then directly compared in terms of the net income delivered and the effective tax rate (net benefit deduction rate). Although the evidence in favour of a US-style EITC is weak, two possible variants are considered. The paper concludes that the only future for an EITC is probably as a partial scheme, linked to the amalgamation of in-work and out-of-work benefits, which removes wage subsidisation from the sphere of social security by means of a semi-individualised tax credit. Even so, the same goals could be achieved through the benefit system. JEL classification: H24, I38.

Notes: Pension systems in different countries vary widely in such aspects as the dependence of benefits on earlier labour income, the minimum permitted retirement age and limits on labour supply after retirement. This paper uses a simulation model of a rational, utility-maximising household facing the detailed pension provisions of eight European countries to study microeconomic distortions induced by the different rules and regulations. We examine in particular the impact on savings, labour supply, retirement age decisions and welfare. JEL classification: H55, J26, J65.

Notes: This paper analyses the windfall tax on the privatised utilities, introduced in the 1997 Budget. It describes the main arguments put forward for the tax and sets out the details of its scope, scale and method of implementation. The tax is examined against the guidelines of economic efficiency, fairness and administrative feasibility. A one-off tax based on past profits should be efficient, provided that the statement that it is one-off is credible. However, as a tax levied on companies, it does not directly tax the windfall gains that were made in the past by shareholders in the companies concerned. JEL classification: H25, L51, L98.

Notes: This paper analyses low income dynamics in Britain using the first four waves of the British Household Panel Survey. There is much low income turnover: although there is a small group of people who are persistently poor, more striking is the relatively large number of low income escapers and entrants from one year to the next. Simulations using estimated low income exit and re-entry rates demonstrate the importance of repeated low income spells for explaining a person's experience of low income over a given period. We also document the characteristics of low income stayers, escapers and entrants.

Notes: This paper considers some of the economic impacts that demographic change may have in developed economies over the next fifty years. I focus on the role that financial markets might play in economies where the pressure on government-run unfunded pension systems is likely to rise. The role of unfunded schemes is considered in a world where financial markets are incomplete and important types of risk cannot easily be offset by trading. How demographic shifts might affect labour productivity, asset prices and aggregate output is investigated using a simulation model of an economy where population structure is changing. JEL classification: E21, E60, G10, H1.

Notes: The ‘Green Book’ and the recent EGRUP report support exchequer cost per job as a key input in the ex-ante appraisal of individual applications for Regional Selective Assistance (RSA) and the ex-post evaluation of the RSA scheme as a whole. In this paper, following a recommendation in the House of Commons Trade and Industry Committee's report on regional policy, the merits of an alternative, explicitly cost-benefit, framework are outlined. This approach incorporates the administration and compliance costs of the subsidy, costs at present ignored in RSA evaluation studies. An optimal ex-ante appraisal rule is developed. This takes the form of a cost-per-job ceiling, and a representative value is calculated for this figure. JEL classification: H20.

Notes: Abstract. The large boreal peatland ecosystems sequester carbon and nitrogen from the atmosphere due to a low oxygen pressure in waterlogged peat. Consequently they are sinks for CO2 and strong emitters of CH4. Drainage and cultivation of peatlands allows oxygen to enter the soil, which initiates decomposition of the stored organic material, and in turn CO2 and N2O emissions increase while CH4 emissions decrease. Compared to undrained peat, draining of organic soils for agricultural purposes increases the emissions of greenhouse gases (CO2, CH4, and N2O) by roughly 1t CO2 equivalents/ha per year. Although farmed organic soils in most European countries represent a minor part of the total agricultural area, these soils contribute significantly to national greenhouse gas budgets. Consequently, farmed organic soils are potential targets for policy makers in search of socially acceptable and economically cost-efficient measures to mitigate climate gas emissions from agriculture. Despite a scarcity of knowledge about greenhouse gas emissions from these soils, this paper addresses the emissions and possible control of the three greenhouse gases by different managements of organic soils. More precise information is needed regarding the present trace gas fluxes from these soils, as well as predictions of future emissions under alternative management regimes, before any definite policies can be devised.

Notes: Abstract. The effects of tree crops on the soil physical properties of former agricultural land were compared with those of ley in a rotation with cereals on adjacent sites. Five sites in southern Sweden were investigated focussing on soil water retention characteristics, dry bulk density, macroporosity and saturated hydraulic conductivity. Three of the sites were on light textured soils and two on clay soils. The tree crops were 30 to 35-year-old hybrid aspen, Populus deltoides, and silver birch, Betula pendula, and the ley crops were one to five years old.The light-textured soils under tree crops showed bimodal pore size distributions in the macropore region, whereas under ley crops they showed unimodal distributions. Dry bulk densities were generally smaller and the macroporosities larger under tree crops compared with leyicereal crops. Saturated hydraulic conductivities tended to be larger under tree crops. Slopes of the linear regression lines between saturated hydraulic conductivity and each of the parameters dry bulk density, porosity and macroporosity were steeper in the soil under agricultural crops than under tree crops.Observed differences in physical properties were considered to be an effect of land use, which had brought about changes in aggregate stability, pore size distribution and pore continuity.

Notes: Abstract. The effects of straw disposal by burning and incorporation on soil and crop nitrogen (N) supply, were investigated on two light textured soils in central (ADAS Gleadthorpe) and eastern England (Morley Research Centre) over the period 1984 to 1995. Nitrogen balance calculations showed that after 11 years of contrasting straw incorporation versus burn treatments, the cumulative N returns in straw were c. 570kg/ha at Gleadthorpe and c. 330 kg/ha at Morley However, these N returns via straw incorporation were not reflected in increased total soil N levels in autumn 1994. There were no differences (P 〉 0.05) between straw disposal treatments in autumn soil mineral N supply, readily mineralizable N or organic carbon. Similarly, there were no consistent differences between the treatments in terms of crop yield, crop N uptake or optimum fertilizer N rates. Fertilizer N applications of 200 kg N/ha/y increased topsoil organic carbon from 1.18 to 1.28% and total N content from 0.091 to 0.102% on the loamy sand textured soil at ADAS Gleadthorpe, but not at Morley. Previous fertilizer N applications increased the quantity of nitrate-N leached in drainage water by c. 20 kg/ha at Gleadthorpe and c. 60 kg/ha at Morley overwinter 1994/95, and by 10–20 kg/ha at both sites overwinter 1995/96. There was some indication overwinter 1994/95 that straw incorporation reduced nitrate-N leaching by 10–25 kg/ha, but there were no differences between treatments overwinter 1995/96.

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

Notes: Abstract. Mubangwe Farm, northern Malawi, was brought into cultivation from savanna vegetation with Brachystegia between 1970 and 1983 to produce tobacco, maize and groundnuts. Because of poor yields even with inputs of lime, N, P and K the fields were soon abandoned. The soils were only moderately acidic with little likelihood of Al toxicity. They held only small amounts of exchangeable Ca2+ (down to 0.01 cmolc/kg) particularly at depth. Phosphorus availability was low particularly in the subsoil. A minus-one pot experiment showed that the growth of sorghum in topsoil samples was limited by lack of N, P, S and Ca. The lower availabilities of P and Ca in the subsoil are therefore likely to be major limitations to growth, allowing only limited root penetration. The loamy sand to sandy clay soils generally had small available water capacities (down to 0.07 cm3/cm3) which, with restricted root development, may have lead to drought in dry periods during the growing season. The findings emphasize the need to measure both subsoil and topsoil properties when new areas of land are being developed for crop production.

Notes: Abstract. Nitrogen (N) leaching losses from a shallow limestone soil growing a five course combinable croprotation (oilseed rape, wheat, peas, wheat, barley) were measured from 1990 until 1995 using porous ceramic cups, at 60 cm depth, and drainage estimates. The crops were grown with three husbandry systems and two levels of N fertilizer. The husbandry systems were designed to reflect local practice (Standard), the best possible techniques to reduce N loss (Protective) and an Intermediate system which was a compromise between the two. Nitrogen was applied at full and half recommended rates. Drainage started during September in four years and November in one year, with above average drainage in three years. Losses of N were largest after peas (58 kg/ha) and oilseed rape (42 kg/ha), and least (17 kg/ha) before peas sown in spring after a cover crop. Over five years, the Protective management system, which used early sowing and shallow cultivation wherever possible, lost least N (31 kg/ha/y) and the Standard system, with conventional drilling dates and ploughing as the primary cultivation, lost most (49 kg/ha/y). Halving the N fertilizer decreased N loss by 11 kg/ha/y, averaged over the rotation. None of the treatments gave mean drainage water nitrate concentrations of less than 50 mg/l, averaged over the five years. Changes to arable cropping alone will not eliminate the need for other measures to control nitrate concen-trations in public drinking water supplies.

Notes: Abstract. Soil salinity and alkalinity reduce plant production and alter species composition of meadow grasslands in western Jilin Province, China. This study was designed to compare the survival and growth of three grass species (Aneumlepidium chinense, Puccinellia tenuijlora and Hordeum brevisubulatum) transplanted into saline-alkali soils in the field, and to evaluate the effects of gypsum amendments on soil properties and growth of these species. Gypsum treatments decreased soil pH, electrical conductivity, and chloride and sodium levels; water infiltration and calcium levels were increased. Survival of grass transplants was increased by gypsum treatments. Tiller number and height, and grass yields were all increased by the application of gypsum. Improvements in plant growth and survival with gypsum treatment appeared to be due to reduced chloride levels and increased Ca availability in the soil, and to changes in soil structure leading to improved infiltration rates. Revegetation of salinelalkaline soils in this region would be improved by application of gypsum in the range of 14–19 t/ha.

Notes: The UK government recently introduced legislation to treat the qualifying distribution on a repurchase of shares in the same way as ‘foreign income dividends’. This paper examines and criticises this reform from two perspectives. First, there is no underlying rationale for such an approach. Second, the legislation moves the tax system away from simplification. A better approach would have been to remove the advance corporation tax (ACT) charge on a repurchase. JEL classification: H25, K34.

Notes: This paper examines the impact of the UK housing benefit system on the financial returns to employment of people in local authority or Housing Association accommodation. It outlines the current structure of housing benefit and examines its effects on the returns to employment using data from the Family Expenditure Survey. It analyses the consequences of a number of reforms to the current system — lowering social rents, increasing the levels of housing benefit received in work and restricting the amount of rent covered by housing benefit payments. This analysis highlights the trade-offs involved in various strategies available for restructuring the present system. JEL classification: H3, H4, J3.

Notes: Abstract. As part of a study of recession farming on the ‘fadama’ lands on a segment of the Komadugu-Yobe floodplain, a survey was carried out to investigate the local farmers’ perception of soil types and management practices. The farmers are clearly aware of the differences in soil type on the fadama and they possess unique skills in managing their farm lands. The farmers classify fadama soils for recession farming by assessing soil texture and soil drainage conditions by feel and observation. Integrating such local knowledge into soil surveys will lead to better practical definition of mapping units and give soil names that have more meaning for the farmers.

Notes: Abstract. Crops grown on virgin upland Vertisols of Zambia, are reported to perform rather poorly. However, subsoiling followed by repeated cultivation over two years apparently improves crop growth. Highest yields were recorded under long-term cultivation (12 years). To evaluate the reasons for these differences in crop response to Vertisol management, physical and hydrodynamic characteristics of soil profiles were studied in three soil management systems. The management systems were: uncultivated or virgin land; land cultivated for two years; and land cultivated for 12 years. The mean soil aggregate size decreased with increased time of cultivation, mostly due to the decrease of the largest sized aggregates. The surface horizon dried more slowly on the long-term cultivation plot. A comparison of the hydraulic conductivities indicated that water intake in the deeper layers improved with increased period in cultivation. Oxygen diffusion measurements showed good aeration at field capacity, to a depth of 0.32m on the long-term cultivation plots, but only to 0.17 m and 0.25 m for 2 years cultivation and virgin plots respectively. Repeated cultivation was beneficial in improving surface soil tilth and in improving subsurface drainage, thus removing the problem of a perched water table which occurred close to the soil surface under natural conditions.

Notes: Abstract. The chemical extractability of heavy metals introduced into the soil during 7 years application of sewage sludge, composted municipal solid waste and sheep manure, and their availability to citrus plants were studied. The total content of metals in the soil (0-20 cm)was increased by the use of sludges and compost, but only the Ni content in the saturation extracts of soil was significantly increased. Total Cd, Cr, Cu, Ni, Pb, and Zn were sequentially fractionated into water-soluble plus exchangeable, organically bound, carbonate-associated, and residual fractions. Most of the heavy metals were present in carbonate and residual fractions, although substantial amounts of water-soluble plus exchangeable Cd, and organically bound Cu and Ni were found. No significant increases in the metal contents in leaves and orange fruits were observed, with the exception of Pb in leaves. Several statistically significant correlations between metal content in plants, metal content in soil fractions, and chemical characteristics of soil were also found.

Notes: Book reviewed in this article: Human impact on Erosion and Sedimentation By D. E. Walling & J.-L. Probst (editors).

Notes: Book reviewed in this article: Soil erosion by water in Africa: Principles, Prediction and Protection By D. Nill, U. Schwertmann, U. Sabel-Koscella, M. Bernhard & J. Breuer.

Notes: Abstract. The projected increase in sewage sludge used on land within many countries in the European Community will provide a major source of entry for several heavy metals into the soil. Although the application rate of sewage sludge to agricultural land is constrained by maximum annual additions of heavy metals, there is a need to know the sensitivity of those soils to heavy metal inputs which are physically suited for application. A rulebased classification using weighted parameters designed to assess the metal binding capacity of soil and the risk of groundwater pollution has been applied to soils data held within the Macaulay Land Use Research Institute's National Soils Inventory The classification uses soil pH, organic matter content, texture and soil colour as a surrogate for iron oxide concentration. The results indicate that some metals, for example cadmium and zinc are potentially more mobile in soils than others such as lead, but that the majority of soils display a strong or very strong binding capacity for all the metals. However this pattern can only be sustained if the soil pH values are maintained at their present values; a fall of one pH unit marks a dramatic shift towards the weak and moderate binding classes. The approach is largely unvalidated but does provide a useful framework for incorporating our mechanistic understanding of processes into wide area soil quality assessments and in identifying future research opportunities.

Notes: Abstract. Kriging is used to provide detailed quantitative information for a range of soil characteristics across the floodplain of the River Gambia. Application of spatial statistics to a large area with a coarse grid of data points produces spurious patterns unless the area is first partitioned into soil-geomorphic mapping units, each of which has a unique pattern of spatial variation. Even combining classical soil survey method with spatial statistics, the large short-range variability of acid sulphate soils means that single factor maps conceal a large element of uncertainty. A more robust procedure is to map the probability of occurrence of critical values of key characteristics.

Notes: Abstract. Ten chalk topsoils (0-25 cm) were repacked into columns in the laboratory. After leaching similar to one year's throughflow in the field, loss of K was equivalent to between 9 and 74kg K/ha. This represented between 3 and 30% of the initial exchangeable K with which loss was poorly correlated. Loss was dependant on the soil solution concentration and was inversely proportional to potassium buffer power.The loss of magnesium in the same columns was between 10 and 22 kg Mg/ha (6-21% of the initial exchangeable Mg). Magnesium loss was poorly correlated with exchangeable Mg.When KCl fertilizer was incorporated into the soils, the increase in leaching of potassium was 1–35% of the K addition. Application to the top of the column resulted in less leaching than when the K was incorporated. Leaching of magnesium was increased by up to 5 kg Mg/ha.Potassium leaching may be delayed by the underlying A/C horizon but pure chalk, with an extremely low buffer power for K, has little ability to retain K. Extremely calcareous topsoils were the most leaky although in practice it is the organic chalk soils on which it is most difficult to attain adequate K levels. On all chalk soils, maintenance of a high K level with K fertilizer is likely to cause unnecessary long-term leaching losses. Annual, rather than biennial, fertilizer applications are to be preferred.

Notes: Abstract. Soils in areas with high livestock density contribute to the eutrophication of aquatic ecosystems through loss of nutrients, especially phosphorus (P). In order to identify the potential for P loss from such soils we determined phosphorus extracted by water (H2O-P), by double lactate (DL-P), and P sorption capacity (PSC) and degree of P saturation (DPS) in soil samples from two counties, one with low (Harle-catchment) and the other with very high livestock density (Vechta). Both catchments are hydrologically connected with the tidal areas of the North Sea.The mean concentrations of H2O-P (0.4mmol/kg) and DL-P (3.9 mmol/kg) were lower in the Harle-catchment than in the Vechta area (1.2 mmol/kg, 6.8mmol/kg). Although oxalate-extractable Al (Alox) and Fe (Feox) and the derived PSCs varied according to soil type and to land use, the livestock density and the resulting high concentrations of oxalate-extractable P (Pox) were shown to be the main reason for the very high DPS of up to 179% in the county of Vechta. These values exceeded DPS reported from other intensive pig feeding areas in western Europe and indicate the potential for significant P loss. Less than 40% of the variation in Pox could be explained by the routinely determined H2O-Por DL-P. Geostatistical analyses indicated that the spatial variability of Pox depended on manurial history of fields and Alox, showed still smaller-scale variability. These were the major constraints for regional assessments of P losses and eutrophication risk from agricultural soils using available soil P-test values, digital maps and geostatistical methods.

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

Notes: Abstract. The impact of soil erosion on soil productivity was estimated for a Rhodic Ferralsol and a Eutric Cambisol in Santa Catarina, southern Brazil. Over equivalent periods, total soil losses were an order of magnitude different (868 and 68 t/ha respectively on the bare soil control), yet the impact on maize yield per tonne of soil lost was far greater at the Cambisol site with less erosion. Similar interesting contrasts between sites were found for the other measures of impact with decline in pH and phosphorus and increase in free aluminium being the most obvious induced soil differences. The results demonstrate the variable nature of erosion impact according to soil type and they highlight the importance of examining a number of measures of impact before pronouncing on the sustainability of any particular agricultural practice.

Notes: Book reviewed in this article: Agricultural Recycling of Sewage Sludge and the Environment By S. R. Smith.

Notes: Book reviewed in this article: No-tillage seeding: science and practice By C. J. Baker, K. E. Saxton & W. R. Ritchie.

Notes: Abstract. The rates of CO2 production and decomposition of 13C-enriched Lolium perenne leaves and roots in soil from the surface five cm of two upland stagnohumic gley soils were measured in laboratory experiments. One of the soils had been limed (pH 6.8) 13 years earlier. The other was unlimed (pH 3.7). Liming increased the rate of CO2 release from soil to which no L. perenne had been added. About 30% of the 13C in L. perenne leaves remained in both limed and unlimed soil after 224 days. By contrast, less 13C-remained in the limed soil amended with L. perenne roots (44%) than in the limed soils (55%). Although the daily rate of CO2 from the plant material-amended soils was initially greater in the improved than in the unimproved soil, it subsequently declined more rapidly.

Notes: Abstract. The characteristics and variability of soils within a 30 ha experimental site in N. E. Nigeria are analysed in relation to tree establishment. Profile description and analyses for some 480 surface samples of the sandy to clayey surface soils from Lake Chad lacustrine sediments provide baseline properties against which any subsequent modifications resulting from agroforestry practices can be assessed and to which initial tree performance can be related. This has been undertaken using principal component and spatial analyses. Inherited soil properties show spatial variations across the site which can be related to the soil textural parameters. The initial survival of trees planted for agroforestry experimentation shows strong correlations with the inherited characteristics of the soil rather than with acquired soil properties.

Notes: Abstract. Field measurements of cumulative infiltration and of the matric potential prior to infiltration were made with double-ring infiltrometers and tensiometers, respectively, on two sandy loams in north-east Scotland. The time to ponding for constant-rate infiltration was also measured in the same infiltrometers by applying water at a constant rate until ponding commenced. Under the range of initial potentials studied (-2 to - 17 kPa), an exponential relation was adequate to describe the relation between sorptivity and initial matric potential. The time to ponding was also strongly dependent on initial matric potential and increased dramatically as the soil became drier. Measurements of time to ponding were in good agreement with values predicted from the theory of Clothier et al. (1981) using values for sorptivity and the A parameter obtained from the cumulative infiltration experiments. Measurements and predictions clearly showed the importance of the sorptivity versus initial matric potential relation in controlling the time to ponding of such sandy soils. These results have implications for determining the generation of runoff and the establishment of stream flows, as well as determining optimum rates and design of irrigation.

Notes: Abstract. When Albania emerged from its seclusion in 1991, the scientific community had its first opportunity to interact with its international counterparts. Soil resource assessment was made with systems developed in the early 1950s, laboratory facilities to provide supporting data were poor, and it was recognized that a new assessment was urgently needed.The country faces a major challenge in reforestation and soil conservation against a background of overgrazing by sheep and goats and clearing of trees and scrubs for fuelwood. Even orchard and olive trees were used as fuelwood during the winters of 1990 and 1991. Since then, gully and rill erosion has accelerated on many of the sloping lands. In addition to reforestation and conservation measures to reduce the pressures on the sloping land, it is necessary to enhance productivity on the fertile valley bottom soils where most of the agriculture is confined. In the recent past, grain yields have declined due to reduced fertilizer use (low purchasing capacity), and poor management practices. More recently productivity has slowly improved, but land degradation, particularly erosion, has visibly increased.USDA Natural Resources Conservation Service in collaboration with the Land Resources Institute of Albania, initiated work on a new national soil map through collation of existing information and field studies. The land unit for land use planning, evaluation, and general management decisions, is the Major Land Resource Area (MLRA). Each MLRA encompasses geographically associated soils, the majority of which have broadly similar patterns ofclimate, water resources, and land uses. The MLRAs presented here are based on the soil map of Albania at 1 : 200 000 scale. The MLRA information provides an overview of the landscape and natural resources. It can be used to assess land suitability for various crops, opportunities to achieve self sufficiency in food production, selection of areas for both field crops and highvalue crops for export, and identification of appropriate farming system technologies. Each MLRA will have a set of degradation processes which can be flagged, therefore each of them becomes a unit for decision making with respect to investments in research and mitigating technologies. The task is far from complete. Appropriate databases are needed to support the decisions that are being made at national level. To complement the MLRA and related database, decision support systems are needed for the important task of developing policy options.

Notes: Widely used summary measures of inequality or the idea of the “disappearing middle class” are potentially misleading. Divergences between evidence cited and conclusions drawn include failing to distinguish between the concepts of inequality and polarization, and using scalar “inequality” measures which are not consistent with rankings based on Lorenz curves. In addition, inappropriate claims about trends in inequality can arise from focusing on only a sub-population such as full-time male workers, and failing to account for sampling variability. These divergences are illustrated using Canadian data on labour incomes over the 1967 to 1994 period.

Notes: There are few sources of high-quality data on the dynamics of wealth accumulation. This paper uses newly available data from the 1983 89 panel of the Survey of Consumer Finances to examine household saving and portfolio change over the 1980s. Our main findings are as follows. First, median household wealth rose modestly over the period. Second, while overall wealth inequality increased, households in the top 1 percent of the wealth distribution in 1983 saw their share of total wealth decline, probably reflecting turnover among the very wealthy. Third, although age, income, and initial wealth had significant effects in regressions on household saving, a large part of the variation in saving was unexplained. Finally, there were clear life-cycle patterns in the portfolios of assets and liabilities held by households, with younger households acquiring homes, businesses and all types of debts, and older households divesting themselves of these assets and debts.

Notes: There is a growing awareness that it is important to understand patterns of family assistance; however, there is still a great deal of information about private transfers that is not known. This study begins to fill this void by presenting results from a new survey and integrating these findings with evidence from recent studies that use other new data sets. It is found that: (i) a large share of households participate in private transfer networks, (ii) a greater amount of financial assistance is provided to lower income family members, (iii) altruism does not fully explain transfer behavior, and (iv) people in their 20s and 30s receive more assistance than people of other ages, even the very old.

Notes: In this paper we analyze the determinants of material inputs into individual production activities as a function of their outputs. We use observations on a large cross-section of U.S. manufacturing plants from the Census of Manufactures, including those that make goods primary to other industries, to study differences in production techniques. We find that in most cases material requirements do not depend on whether goods are made as primary products or as secondary products. We thus elucidate support for the commodity technology model as a useful working hypothesis.