ALBERT

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

Notes: Abstract. Soil cores from river marginal wetlands in the UK, France and Ireland, sampled and contained within PVC piping, were flooded with nitrate-N enriched water. Half of the cores were sterilized prior to flooding to destroy the denitrifying bacteria. The change in nitrate-N concentration in the floodwater was measured over time. It is argued that the observed nitrate depletion rates (from 0.4 to 2.3 kg/ha per day) may be identified With microbially-mediated denitrification. The results show the method to be a simple and direct procedure for the assessment of spatial variation in nitrate-sink capacity. The depth of the denitrifying layer at the soil-water interface was confirmed to be of the order of a few mm.

Notes: Abstract. We examined whether nitrogen (N) and phosphorus (P) export was enhanced from grassland receiving inorganic fertilizer and manures typical of intensive livestock production. Buffer strips were included in the study to determine if they could reduce nutrient export. Hillslope plots receiving granular inorganic fertilizer, liquid cattle slurry and solid cattle manure (FYM) were compared using rainfall simulation for 4 storms on consecutive days at 22 mm h-1 and 35 minutes duration. The plots were hydrologically isolated in a randomized block layout of 4 treatments × 3 replicates and measured 30 × 5m; the upper 20m received either fertilizer, slurry or FYM, while the lower 10 m acted as an unfertilized grass buffer strip. Nitrogen and P export in surface runoff from grassland receiving inorganic fertilizer exceeded that from FYM or slurry treatments; concentrations up to46mgN1--1 and 15 mgP1–1 were recorded.Sixty eight % and 62% of the N from FYM and slurry respectively, was exported in organic form. Seventy four % (FYM) and 39% (slurry) of the P was in particulate or dissolved organic form. The buffer strip reduced N export in surface runoff by 94% and P export by 98% from inorganic fertilizer plots. A 75% reduction in N export was recorded from the buffer zone below slurry plots but only a 10% reduction in P, with most P remaining in the particulate or dissolved organic fraction. There was no significant difference in N export from the buffer zone between the inorganic fertilizer treatment and the untreated control.

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

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

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

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

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