bluuebunny/crossref_metadata_2025 huggingface dataset:
Erosion control practices applied to granitic roadfills for forest roads in Idaho: Cost effectiveness evaluation
Authors: Megahan W. F. , Monsen S. B. , Wilson M. D. , Lozano N. , Haber D. F. , Booth G. D.
Published: February 2007

Cost effectiveness of six alternative road embankment construction practices and 16 alternative fill‐slope stabilization practices was evaluated as means for controlling erosion on forest roads built on granitic soils in Idaho (USA). A total of 63 bordered erosion plots 1‐8 m wide by 4‐6 m long, were used. Eroded material was collected in troughs at the bottom of each plot in the spring and fall. Measurements began in the fall of 1981 and continued until the fall of 1983. Costs were obtained by tabulating actual labor, equipment, and supplies used to install the treatments. Rainfall erosivity values accumulated for the snow‐free periods between erosion measurements proved to be a statistically significant covariate for the analysis of treatment effects. There were no significant differences between the three embankment construction practices (sidecast, layer placed, and controlled compaction). But surface rolling did significantly increase erosion in all cases. Nine of the post‐construction soil stabilization measures significantly reduced erosion, and one measure significantly increased erosion (P < 0‐5). Stabilization measures that combined mulches with revegetation appeared to be more beneficial for erosion control than either mulches or revegetation alone. Rankings of the erosion control effectiveness of individual soil stabilization practices were different from the rankings of the cost effectiveness of the practices. Application of alternative treatments is discussed.
Should all degraded landscapes be restored? a look at the appalachian copper basin
Authors: Quinn M.‐L.
Published: February 2007

Rehabilitation of degraded landscapes is generally regarded as the most appropriate objective. Occasionally, however, other aspects of the situation need to be considered and may lead to a different decision. This paper presents the case of the Appalachian Copper Basin, located mainly in south‐eastern Tennessee, USA, which was degraded years ago as a result of copper mining and smelting. A brief history of the site is given, along with a review of some rehabilitative efforts. Discussion then turns to the way visitors and residents perceive this landscape, the impact these two viewpoints have had over the years, and how they have (or have not) changed. Landscape values are also examined, the interpretation of which largely determines a person's opinion toward rehabilitation. The point is made that some degraded landscapes can have value as degraded landscapes, in this instance now primarily historical and cultural. The current situation in the Copper Basin is summarized and an alternative course of action suggested. It is concluded that rehabilitation is not always the only, or even the most important, goal and that degraded landscapes of long standing sometimes require special consideration.
Amelioration of a highly degraded tropical alfisol by planting I. Changes in soil physical and chemical properties 1989‐91
Authors: Hulugalle N. R.
Published: February 2007

This paper examines soil amelioration by planting 15 leguminous and graminaceous plant species, including herbaceous annuals, perennials and biennials, and woody perennials and biennials. Disturbed and undisturbed natural regrowth were planted with leguminous species, in some cases with fertilizer applied at planting (400 kg ha−1of 15:15:15 NPK). The studies were made on two highly degraded sites in southwestern Nigeria which had been subjected to intensive mechanized cropping for a period of 10 years. Changes in soil physical and chemical properties were monitored from 1989 to 1991.Acacia difficilis, Brachiaria lataandMucuna utilishad the lowest survival rates by the following growing season. Soil fertility and compaction levels differed between sites. Planting had no effect on the latter. The decreases in compaction (i.e. macroporosity) between 0.00 and 0.10 m depth at both sites one month before and five and 17 months after planting were 43, 59 and 61 per cent, respectively were attributed to exclusion of heavy machinery from the sites. Large decreases in fertility occurred at both sites and were attributed to a combination of nutrient extraction and to leaching. Between fallow species, exchangeable Ca, pH and the cation‐exchange capacity (CEC) were greater and total acids lower for herbaceous cover compared with woody perennials, and was attributed to a higher Ca demand by the latter. Highest and lowest values of Ca, CEC and pH occurred in plots where plant material was returned to the soil (i.e. by cutting or die‐back) and in cropped plots, respectively. Natural regrowth was as effective or better than planted species in improving soil physical and chemical properties. Therefore the use of exotic plant species for ameliorating highly degraded alfisols is unnecessary. Amelioration of highly degraded alfisols may be best effected by allowing natural regrowth to occur while excluding all mechanized traffic from the site.
Re‐establishing life in restored topsoils
Authors: Scullion J.
Published: February 2007

Surface mining activities and other large civil engineering works often involve the removal, storage and reinstatement of topsoil. Disturbance disrupts normal biological functions within the soil and can markedly change the environment within which soil organisms must exist. This has implications for soil fertility and for the overall ecology of replaced land. A number of studies have investigated the impact of opencast coal mining practices on soil organisms and their capacity for recovery following site reinstatement. The extent and duration of any adverse effect varies from one group of organisms to another according to their vulnerability to damage, their capacity for recovery and their ability to recolonize areas from which they have been eliminated. Three groups of organisms—earthworms, aerobic bactería and vesicular arbuscular endophytes—are considered, to illustrate their differing responses to soil disturbance and the various factors limiting their early recovery throughout a restored area. Given favourable management, consistent with good general rehabilitative practice, the re‐establishment of normal earthworm populations depends entirely on the distribution of an inoculum. For aerobic bacteria adverse physical conditions in reinstated soils are the overriding influence determining levels of activity. For mycorrhizal fungi both soil conditions and the absence of an inoculum may delay recovery, although the evidence in support of this view is inconclusive.
Degradation of ‘reclaimed’ lands previously disturbed by coal mining in Wales: Causes and remedies
Authors: Haigh M. J.
Published: February 2007

Large tracts of land, officially described as ‘reclaimed’ from former mineral workings, are in poor condition. Problems include gullying, soil erosion, soil compaction, accelerated run‐off and poor vegetation cover. Some of these problems are caused by low quality and inappropriate engineering. Some are due to poor land husbandry. There is a need for a national system of quality control inspection for land reclamation sites and provision for training in the special problems of managing reclaimed lands. However, many further problems result from natural soil‐forming processes, notably the accelerated breakdown of newly exposed minestones. This chokes the soils with fine particles, decreasing permeability and increasing bulk density. Current research directed to correcting this problem uses trees to build new self‐sustaining soils from the ground up and to promote the development of a large and active community of soil organisms. It is hoped that the polysaccharide secretions of these organisms will bind the newly created clays into stable soil aggregates.
Development of pollution‐neutralizing properties in very young mine soils
Authors: Gil‐Sotres F. , Leirós M. C. , Trasar‐Cepeda M. C.
Published: February 2007

Various properties capable of neutralizing environmental pollution (aggregate stability, buffer capacity and ion adsorption capacity) were determined in spoil from a lignite mine in Galicia (northwest Spain) and in mine soils of four and seven years age developed from this spoil. Buffer capacity and the adsorption of copper, cadmium and phosphate increased markedly with soil age, whereas the dispersion ratios of both macro‐ and micro‐aggregates decreased sharply. These changes are attributed to the known increase in organic matter and extractable iron and aluminium. These components aid interparticle binding and create both exchange sites and specific adsorption sites. The ultimate causes are thought to be the successful establishment of an active field plant cover, the considerable colloid content of the parent material, the management of the mine soils and the climatic conditions of the area, which favour both the accumulation of soil organic matter and the weathering of the parent material.
Terracing and accelerated soil loss on rwandian steeplands: A preliminary investigation of the implications of human activities affecting soil movement
Authors: Lewis L. A.
Published: February 2007

Throughout Rwanda, terracing was reintroduced in 1973 as the major conservation practice to minimize soil loss on its steep agricultural lands.1 Terracing has been partially successful in reducing soil losses resulting from nonchannelized runoff, the goal of this practice. However, because of the widespread fragile environmental conditions in the highlands, soil fertility has decreased and soil acidity increased in numerous fields as a direct result of the terracing. To maintain sufficient agricultural yields, within the constraints of a low resource agricultural system, farmers have responded to the acidity and soil fertility problems by systematically removing a portion of the terrace berm during field preparation. This practice, in response to the changing environmental situation due to terracing, results in significant amounts of soil displaced downslope year after year. This human‐induced soil erosion process seriously counters many of the intended benefits of terrace construction and is contributing to the land degradation problem. The results of this study emphasize the need for both conservation strategies and the measurement of soil loss to be sensitive to human‐induced as well as natural erosional processes. By not considering the human response to terrace construction, the benefits of this conservation practice have been seriously offset.
Afforestation as an interim measure to improve reclaimed lands in singapore
Authors: Lee S. K. , Goh K. C. , Yee S. O.
Published: February 2007

Land reclamation using clay and sand materials has been used to increase land area in Singapore. Although some of these areas are put to immediate use, others are ear‐marked for future development. in the latter instances, in the interim period, afforestation measures involving some treatment of the land have been adopted. This paper discusses the process of afforestation at two sites with different but poor soils and the performance of the different species of trees planted (which are now 12 years old). the benefits of such an afforestation exercise are convincing and a similar but less expensive process could be adopted to afforest reclaimed lands or rehabilitate derelict lands in developing countries to provide wood for fuel or other purposes.
Assessment of soil degradation in the Canary Islands (Spain)
Authors: Rodr Rodríguez A. Íguez , Gonz Soto M. C. ález , Hern Hernndez L. A. ández , Jim Mendoza C. C. énez , Ortega González M. J. , Padr Padrón P. A. óN , Torres Cabrera J. M. , Vargas Chávez G. E.
Published: February 2007

In the Canary Islands a number of factors, both natural and induced by human activity, act on the fragile ecosystems and agricultural land to cause increasing problems with desertification and progressive degradation of soil productivity. the results of an assessment of soil degradation in the Canary Islands, The processes, causes and impacts, are presented in this paper. Although several processes and factors contribute to soil degradation in the Canary Islands, two have been found to exert a greater qualitative influence: (a) accelerated erosion (water and aeolian); (b) salinization‐sodification (natural and induced by agricultural use).

Approximately 40 per cent of the Canary Islands' land is undergoing rapid erosion. the factors involved May, be grouped into: natural erosion—torrential rainfall, sparse vegetation, high soil erodibility, rugged relief; and erosion due to human activities—unsuitable management of arable soils on the steep slopes, overgrazing and deforestation. About 60 per cent of the surface of the archipelago, including areas given over to intensive agriculture, is affected by salinization.The main factors responsible are: natural—an arid climate and a regime of oceanic winds; and human activities—overexploitation of the aquifers, irrigation with water having a high salt and/or sodium content, intensive monoculture, and excessive and indiscriminate use of chemical fertilizers and other agrochemicals.
Human use of the sand dune ecosystem in the semiarid zone of the Rajasthan Desert, India
Authors: Kumar M. , Bhandari M. M.
Published: February 2007

Sand dunes form one of the most fragile terrestrial ecosystems. in Rajasthan they have a diverse vegetation and are often utilized by considerable human and livestock populations. a thorough knowledge of the resource utilization by the human and animal populations is essential if the future potential of the ecosystem and its physical stability under changing environmental conditions are to be accurately assessed. This study examines the socio‐economic aspect of land degradation at four sites in Churu and Jhunjhunu districts, northwest Rajasthan. an attempt is made to assess the socioeconomic factors leading to land degradation. Data on human use of the Rajasthan (Thar) Desert semiarid ecosystem were collected through individual interviews, group discussions and field measurements. the present exploitation of soil and vegetation resources, possible future biomass deficiency, its impact on sustainable development and role in land degradation are examined.

The average number of people in each household in the study area, and the number of livestock each household maintains are too high to allow a satisfactory income to be sustained. the annual income of 50‐90 per cent of households was less than 10 000 rupees ($US 1 = 17 rupees in 1987). Sale and consumption of milk, wool, surplus animals and wood provide livelihood, supplemented with income from wage labour. Rain‐fed marginal land cultivation produces poor yields and the per capita production is too low to justify the huge soil erosion losses occurring. the number of goats, sheep and cattle owned by the inhabitants has increased tremendously in recent years. Stocking rates vary from 1.63 to 12.08 animals per hectare. the grazing pressure during the dry season, when forage availability decreases, reaches 34.9 animals per hectare. as a result of overgrazing, The land productivity has decreased considerably. the annual fodder deficit values in the study area are enormous. Demand for fuelwood at all the study sites is increasing, yet available forests have already largely been cut down. the distance travelled to collect fuelwood has been increasing, whereas the amount and quality of fuelwood is decreasing. Use of cattle dung to supplement fuelwood during the summer dry season and in drought periods has been decreasing due to low fodder availability and high livestock mortality. Human numbers are increasing, and livestock numbers are also multiplying (except in drought periods) and consequently the available resources are decreasing. Soil erosion and desertification will continue to increase during the next decade unless effective counter measures are undertaken.
Enhancement of revegetation on construction fill by fertilizer and topsoil application: Effect on mycorrhizal infection
Authors: Claassen V. P. , Zasoski R. J.
Published: February 2007

The influence of topsoil and fertilizer application on denuded road construction sites was evaluated to assess its contribution to improvement of vegetation re‐establishment. the study sites were within a mixed hardwood and conifer forest on crushed, unweathered subsurface material with low fertility and low biological activity. Topsoils were removed from the site, stockpiled and reapplied to the site after construction. the effect of topsoil amendment on plant growth, soil fertility, mycorrhizal infection and an index of microbial biomass were measured in field and greenhouse experiments. Plant growth on the topsoil amended field plots were greatly increased relative to treatments with fertilizer but no topsoil. Three years after establishment, dry weight production on the plots without topsoil treatment was about 40 per cent of the plots treated with topsoil. Greenhouse experiments were designed to compare fresh, dried and stockpiled topsoil. These experiments indicated that storage of the harvested topsoil for five months in a stockpile had minor effects on plant growth, soil fertility, mycorrhizal infection and microbial biomass. Topsoil volumes had to exceed 20 per cent of the total soil volume to achieve statistically significant benefits and higher ratios showed greater benefit. the percentage of mycorrhizal infection was greatest in topsoil treatments without fertilizer. the addition of fertilizer increased growth but reduced the percentage of roots forming mycorrhizae. When the total weight of infected roots was calculated, however, infection was found to be greatest with a moderate level of fertilizer (equivalent to approximately 27 kg N ha−1 and 39 kg P ha−1), and was less in both higher fertilizer treatments and in unfertilized treatments. Topsoil amendment increased microbial biomass nitrogen but fertilizer treatment did not.
Evaluation of Eucalyptus Camaldulensis (river GUM) and Chamaecytisus Proliferu (Tagasaste) for salinity control by agroforestry
Authors: Eastham J. , Scott P. R. , Steckis R. A.
Published: February 2007

Components of the soil water balance were measured over a three year period for Eucalyptus camaldulenis and Chamaecytisus proliferus, species commonly used for revegetation in Western Australia, and compared with water balance components for pasture. Marked seasonal trends in evapotranspiration were observed for all species with maxima occurring in the wet months, and minima occurring in summer when rainfall was low and evaporative demand high. in each year of study, annual evapotranspiration and soil water depletions were greater for both tree species than for the pasture, due to the greater extraction of soil water at depth. Upward movement of water from the saturated zone was also found to be greater beneath the deeper rooted perennials than beneath pasture.
Establishment of trees on mixtures of pulverized fuel ash and Gypsum. Part II: Nutrition and trace elements
Authors: Shaw P. J. A. , Moffat A. J.
Published: February 2007

Nutrients and trace elements were determined in the foliage of nine tree species grown in mixtures of pulverized fuel ash (PFA) and gypsum. No serious macronutrient deficiencies were observed. Treatments with PFA consistently increased foliar levels of boron, potassium and molybdenum, and the poor performance of some tree species in pure PFA was attributed to boron toxicity. Gypsum hindered the uptake of boron when mixed with PFA, however, and co‐disposal of the two wastes could be used to minimize problems associated with boron toxicity.
Losing ground? soil loss and erosion in the highlands of papua new guinea
Authors: Sillitoe P.
Published: February 2007

First impressions suggest that the risk of soil loss through fluvial erosion from land under cultivation is considerable in the Southern Highlands Province of Papua New Guinea. the climate is very wet all year round, The terrain precipitous, and people regularly farm on steep slopes. the Wola‐speaking people, who occupy a series of valleys in the centre of the province, and who practice a semi‐shifting form of cultivation, are nonetheless off‐hand about soil conservation and declare that erosion is not a serious problem. This paper assesses the status of their assertions by calculating potential soil loss rates. It applies the universal soil loss equation to data on rainfall erosivity, soil erodibility, slope length and steepness, vegetation cover and conservation measures, to compute likely runoff losses. the calculations suggest that, The steep slopes cultivated and wet climate notwithstanding, The local population's assessment of the dangers of erosion is realistic and not reckless. Although rainfall is high, it is rarely of an intensity sufficient to threaten serious soil erosion losses. the physical properties of the soils, which feature volcanic ash components and high organic matter levels, are such that they are particularly resistant to erosion. the staple crop of the region, sweet potato (Ipomoea batatas), also gives particularly good ground cover and protection when established, effectively shielding the soil from erosive rainfall.
Ecological sustainability and the use of chemicals: Is ecotoxicological risk assessment doing its job properly? An introduction to chemical time bombs
Authors: Hekstra G. P.
Published: February 2007

Ten million chemical substances are registered scientifically, but only 1 per cent, 100000, are known to be traded internationally, and only a fraction of these are assessed to establish (eco)toxicological risks through international and national authorities. Only a few of the substances are natural or systemic; most are xenobiotic and poorly evaluated with respect to their environmental effects. It is not only the chemical accidents that make newspaper headlines, but the creeping accumulation of pollutants in soils, sediments and groundwater which degrade the environment for future generations. Ecotoxicological risk assessment still neglects this ‘hidden pollution’, as it usually deals only with the bioavailable fractions of chemicals in the environment. the ‘lost’ (residue) fractions, however, can have non‐linear and time‐delayed effects (chemical time bombs).

As governments need to protect their natural resources (soils, sediments, groundwaters) against negative impacts from chemicals, an ecosystem approach May, help them to overcome the shortsightedness of current ‘acute’ ecotoxico‐logical risk assessments. the Netherlands' risk philosophy on chemicals in the environment is discussed as an example. the National Environmental Policy Plan‐2 (1994) stresses the chain of events associated with a chemical from the raw material, The side effects of its transport, production, use and disposal, to its final effects in the ecosystem, including the time‐delayed responses of pollution. a revised ecotoxicological assessment policy under the new NEPP will have to take account of such chemical time bombs.
Assessment of pollution of groundwater by atrazine
Authors: Kuhnt G. , Fránzle O.
Published: February 2007

Atrazine has been used as a powerful herbicide in maize production for about 30 years, but since it became clear that it threatens the quality of groundwater its use has been forbidden in Germany and elsewhere. Nevertheless the risk to groundwater will remain for a considerable time, and this time will vary depending on the soil type. a classification and mapping procedure for groundwater sensitivity has been developed and the risk of groundwater pollution by atrazine assessed. Specific regions of Germany at high risk have been identified using a computer model and statistical data.
Salinization of groundwater and the mobilization of micropollutants: Effect on the food chain
Authors: Th. Scholten M. C. , Szabolcs I.
Published: February 2007

Although the development of salinization in European soils and waters is less of a problem than in Asia, Africa and Australia, The impact in Europe is likely to be worse because of the much greater interference with stored pollutants. Three types of salinization are discussed here: salinization caused by faulty irrigation, increased evapotranspiration and rises in sea‐level. the potential activation of the chemical time bombs due to climatic changes and the development of the co‐tolerance of plants to metal pollution and increased salinity is considered.
Pollution of sediments in the lake ladoga catchment area and the gulf of finland: influencing factors and processes
Authors: Ikonnikov V.
Published: February 2007

Sedimentation in the estuary of the Neva River (Gulf of Finland) has been significantly altered in recent years by the construction of a flood prevention barrier for St Petersburg. Concentrations of toxic organic substances and heavy metals have increased 1‐5‐3‐0 fold. a shift in sediment redox potential has occurred in most of the fine‐grained particles and the concentration of dissolved oxygen in the bottom waters has decreasd to 0‐5‐1‐0 mg 1‐1. the changing environmental conditions and intensive human activities in the area have led to the remobilization of the sedimentary material, threatening the ecosystem with secondary pollution. Not only direct industrial discharges are responsible for the contaminants identified; human activities throughout the catchment area and atmospheric deposition affect the capacity of the ecosystems to absorb pollutants and result in the increased migration of persistent pollutants into the Neva estuary.

The functions, factors and processes contributing to the transport and sedimentation of toxic substances in the drainage basin of the Lake Ladoga/Neva River system is discussed. Physical (deforestation, drying of marshes) and chemical factors (industrial pollution, agrochemical use) are reviewed. the role of eutrophication in Lake Ladoga in influencing the migration and bioavailability of toxic substances is discussed with respect to its function as a filter and bioreactor. the temporal and spatial variations in the distribution of suspended and dissolved matter in the lake, which is dependent on its morphometric and hydrological characteristics, change the patterns of transport of toxic substances into the Neva estuary. the ecological status of the Neva estuary is reviewed with particular emphasis on the concentration of pollutants in sediments, redox shifts and dumping and drainage activities. the role of gas production and evolution in the remobilization of lipophilic organic substances is considered to be of major importance in shallow estuaries such as this.
Soil and sediment contamination by persistent organic pollutants in the Moravian and Slovakian parts of the danube catchment area and some Bohemian sites in the elbe catchment area
Authors: Holoubek I.
Published: February 2007

Polychlorinated biphenyls, polychlorinated dibenzo‐p‐dioxins and dibenzofurans, HCBs and p, p'‐DDE were determined in soil and sediment samples from selected sites in Czecho‐Slovakia. for the first three groups of chemicals soil pollution in Czecho‐Slovakia is very high. in general, The pollution is higher in the Elbe than in the Danube catchment sediments.
Heavy metal and chlorinated hydrocarbon contamination of selected aquatic sediments from the Berlin area
Authors: Pachur H.‐J. , Ahrens M. , Ricking M. , Röper H.‐P.
Published: February 2007

Sediments from the Berlin area were analysed for heavy metals and chlorinated hydrocarbons. the sedimentological and hydrogeological aspects of the Holocene sediments are discussed and an adapted sampling device for muds with a high water content is described. the contamination of surface sediments and dated cores is shown back in the 19th century; the hydrological influences on the degree of contamination and potential threats to groundwater and, via remobilisation, to surface waters are considered. It is concluded that the sediments of the Berlin area are highly contaminated.
High levels of chlorinated aromatic compounds in deep rhine sediments with special reference to microbial transformations
Authors: Beurskens J. E. M. , De Wolf J. , Van Heuvel H. Den
Published: February 2007

Sediment cores were taken from the Ketelmeer, a sedimentation area of the River Rhine located in the central part of the Netherlands. Chlorinated benzenes, biphenyls, dibenzo‐p‐dioxins and furans were determined in all or in a selected number of core samples. Levels of these compounds since the late 1930s were established using radionuclide tracers and area‐specific geological time markers. Unexpectedly high concentrations of chlorinated dioxins and furans were found in layers that were deposited in the 1960s and 1970s. the highly toxic 2,3,7,8‐TCDD reached concentrations up to 400 ng kg−1 in the mid‐1960s. Post‐depositional redistribution of pollutants was verified by analysing deeper layers that were unpolluted at the time of deposition. Downward transport was only found for some di‐ and trichlorobenzenes. Possible transformations in the anaerobic sediment were evaluated by analysing sediment top‐layer samples taken in 1972. Supported by laboratory experiments, it became clear that some polychlorinated biphenyls and chlorobenzenes had been microbially dechlorinated in the anaerobic sediments. Up to 80 per cent of the input in the early 1970s has disappeared. on the other hand, The accumulation of a dechlorination product, 1,3,5‐trichlorobenzene, from hexachlorobenzene transformation was found. This dechlorination product is less hydrophobic and therefore more mobile than the parent compound. This phenomenon is of particular concern with respect to groundwater quality.
Chemical time bombs from landfills: Appraisal and modelling
Authors: Boels D. , Fleming G.
Published: February 2007

About 240 x 106 tonnes of industrial waste, 104 x 106 tonnes of municipal waste and more than 60 x 106 tonnes of sediment sludge are landfilled (65 per cent), incinerated (24 per cent) and partly recycled in Europe annually. About 60000‐120000 landfill sites, occupying 800‐1700 km2, are recorded in the EEC, of which a limited number are in operation. These sites generate 12.5 x 109 m3 of landfill gas annually, of which about 755 x 106 m3 are presently recovered, and 0‐1‐4‐0 x 106 m3 of heavily polluted leachate, which is dispersed to ground and surface waters. the area with polluted groundwater increases annually by 1‐10 per cent (1200‐12000 km2 of contaminated land). Landfill gas contains carcinogenic and pathogenic components and contributes 2 per cent of the total emission of greenhouse gases; locally it is a potential hazard. Incinerators reduce the solid volume to about 30 per cent of the original but cause the atmospheric deposition of acids and dioxins. Emissions of landfill gas, leachate and atmospheric deposition have been recognized as potential chemical time bombs (CTBs). Models are currently available for the estimation of the time at which the effects of these CTBs will become manifest. It is recommended that an inventory of all landfills should be made to assess the potential hazards in detail, to encourage institutions to initiate the clean‐up of contaminated sites and the aftercare of closed sites, and to set up a co‐operative network within the EEC.
Effects of sewage sludge disposal
Authors: Van Berg J. J. Den
Published: February 2007

The disposal of sewage sludge affects the environment as the sludge May, contain harmful components such as pathogenic organisms, organic compounds, heavy metals and excess phosphorus and nitrogen. Depending on the method of disposal, these effects can be immediate or time‐delayed and non‐linear. the effects of dumped or landfilled sewage sludge can be characterized through its leaching capability, which depends on the treatment before dumping. Treatment May, be simple dewatering or advanced incineration, wet oxidation or immobilization. Leach‐ability is considered here.
Contribution of Czecho‐Slovakia to the chemical time bombs study in the danube catchment area
Authors: Petrovič P.
Published: February 2007

An overview is given of the activities of Czecho‐Slovak institutes within the project ‘Long‐term risks for soils, sediments and groundwater in the Danube catchment area,’ as accepted in 1991 by six riparian countries from the Danube basin. the project is divided into: screening maps; analytical methodology; (bio)monitoring; use of geographical information systems (GIS) for data storage and presentation of results; soil vulnerability studies; modelling of processes; and case studies. Twenty‐six tasks are listed, together with authors and addresses of co‐operating organizations included in the Czecho‐Slovakian project. in the initial stages information was gathered to produce maps of hot‐spots in the Czecho‐Slovakian territory of the Danube catchment area. a list of landfill sites is almost ready; surface water pollution for the Danube itself and for the Hron tributary has been evaluated and some proposals for the presentation of the results have been considered. the methodological part of the project summarizes the analytical methods for the groundwater study. Base levels and standards for the comparison of quality have been completed. At present the Water Research Institute is planning to process the results using ILWIS (Integrated Land and Water Information System), which is distributed by ITC (Enschede, The Netherlands) and VITUKI (Hungary). Some administrative and budgetary aspects of the task are considered and the acute need for closer international cooperation is emphasized.
Technical, policy and legal aspects of chemical time bombs with emphasis on the institutional action required in eastern Europe
Authors: Appelgren B. G. , Burchi S.
Published: February 2007

Technical, economic and institutional conditions are changing rapidly in Eastern Europe. the area has inherited a high level of chemical pollution of soil and water resources, leading to grave risks of chemical time bomb effects. With the current financial and manpower constraints and the general stress on the new economies of the subregion, any substantial environmental improvements reversing past trends will require considerable time, during which chemical pollutants will continue to accumulate in soils and waters. Special emphasis is given to diffuse and accelerated pollution from inappropriate or changed land uses. It is suggested on the basis of recent legislation on transboundary and national chemical pollution in Europe that national policies, priorities and legislation shoud be developed throughout Eastern Europe.
Effect of crop rotation and residue management on properties of cracking clay soils under irrigated cotton‐based farming systems of new south wales
Authors: Hulugalle N. R. , Cooper J.
Published: February 2007

The effects of planting cereal or leguminous crops in rotation with irrigated cotton (Gossypium hirsutum L.) on the properties of cracking clay (swelling) soils in the Macquarie and Namoi Valleys of New South Wales, Australia were evaluated during the summer of 1992–3. The observations were made on commercial farmers' fields. The soil properties evaluated were the particle size distribution, the dispersion index, the plastic limit, the percentage of coarse (particle diameter 212–2000 μm) and fine (particle diameter 53‐212 μm) particulate soil organic matter, soil respiration rate, soil reactivity, soil aggregate density, pH, nitrate‐N and exchangeable Ca, Mg, K and Na. In general, the planting of rotation crops decreased the dispersion index, plastic limit and soil aggregate density, and increased the amount of coarse particulate organic matter. Planting rotation crops also resulted in significantly higher clay and lower silt contents in the Macquarie Valley, and significantly higher soil respiration in the Namoi Valley. Soil pH, nitrate‐N and exchangeable cation concentrations were not significantly affected by planting rotation crops in the Macquarie Valley, whereas exchangeable Na was increased in the Namoi Valley. The retention of crop residues in situ, compared with burning crop residues, decreased the dispersion index, plastic limit and aggregate density, and increased the amount of coarse particulate soil organic matter at all measured depths of the Macquarie Valley. The retention of crop residues in the Namoi Valley decreased the plastic limit and dispersion index only in the 0–50 mm depth range, whereas burning crop residues increased exchangeable K at all depths. In general, planting rotation crops and the retention of crop residues had greater beneficial effects on the soil physical properties in the Macquarie Valley than in the Namoi Valley, and in the topsoil compared with the subsoil. These differences are attributed to a shorter rotation interval in the Namoi Valley, smaller amounts of coarse particulate soil organic matter in the subsoil, and differing soil types in the two valleys. In the Namoi Valley the coarse organic matter produced by leguminous crops appeared to be more effective in promoting structural stability than that from non‐leguminous crops, although no such difference was observed in the Macquarie Valley.
Planning strategies and funding modalities for land rehabilitation
Authors: Kessler J. J. , Laban P.
Published: February 2007

A framework for planning development strategies for sustainable land use in developing countries is proposed based on the carrying capacity concept. The rehabilitation of degraded land includes a stabilization and a restoration phase, with corresponding measures to be taken and funding modalities to be explored. Restoration measures focus on the rehabilitation of ecosystem functions, but are effective only when preceded or accompanied by measures stabilizing exploitation levels. Short‐term benefits are required to ensure local participation, but may be counterproductive when long‐term ecological rehabilitation is the major objective. Incentives are important policy instruments to enhance participation by rural communities in rehabilitation activities. Long‐term economic, ecological and social (humanitarian) arguments, at a scale surpassing the local level, should receive more attention in the process of justifying investments for land rehabilitation. Some criteria and conditions to be met both at a macro‐scale and at the local level are discussed.
Land evaluation in an area of severe erosion: The loess plateau of china
Authors: Fu B. , Gulinck H.
Published: February 2007

Land evaluation is an important basis for landscape and land use planning. A framework was developed for land evaluation in an area of severe erosion, focusing on integrative, process and ecological analyses. Two classification systems, soil quality and erosion risk, were combined in the land evaluation framework. The Quanjiagou catchment, with typical loess hill and gully topography, in the loess plateau of China was selected as the study area. A geographical information system (GIS) was used for data storage, analysis and display. The soil quality classification was based on the main characteristics of the soils (soil organic matter, effective depth of soil and soil moisture); four soil quality classes were defined in the study area. Slope, micro‐landform type and the type and processes of soil erosion were integrated to classify the erosion risk. The soil qualities and erosion risk for each site were combined using the GIS to evaluate the suitability of the land for farmland, grassland and forest. By comparing these results with the current land use, measures for better land use and conservation are suggested.
A legacy of competing imperatives: Environment and development in australia since 1788
Authors: Powell J. M.
Published: February 2007

Australia's environments have been dramatically transformed by immigrant communities who were impelled by a simple utilitarian dream and obliged by geographical and historical circumstance to contend with accumulating uncertainties, including those connected with the operation of Nature's own independent dynamic. With the exception of a few critical junctures and significant but highly localized settings which are reasonably well supplied with primary material, the historical records are scarcely satisfactory for fine‐textured reconstructions of changing physical landscapes. There is certainly some potential for very broad ‘indicative’ stocktaking, but unavoidable imprecisions and the irritating problem of discontinuities rule out the most ambitious of International Geosphere‐Biosphere Programme (IGBP) style studies. Therefore a major premise of this discussion is the acceptance that we are obviously better placed to offer a range of underpinning social, political and economic analyses than to launch into the production of confident, large‐scale reconstructions of the past ‘faces’ of Australia. The bulk of this paper explores that proposition and is confined to such analyses. On the other hand, it also suggests that the time is ripe for tailoring novel co‐operative research into landscape change in the ‘European’ era, especially by combining physical and documentary evidence in the investigation of carefully selected sites and situations.
Land use choices in a changing world
Authors: Chisholm A. H.
Published: February 2007

The primary factors which are likely to mould future non‐urban land use patterns in Australia are identified. Over the past three decades the rate of increase in land productivity in Australia has been higher than for any other OECD country. Land degradation does not appear to have seriously threatened agricultural output over the last 45 years. However, there is cause for concern that land degradation, attributable to past activities, may only now be exerting a significant impact on productivity in some regions. Many of the services provided by natural resources have been underpriced; consequently, there has been a bias in agricultural research towards technologies that enhance on‐site productivity, but which impose excessive external social costs. Underpricing of native trees from state‐owned and managed forests appears to have caused excessive exploitation of these forests and lowered the establishment of softwood and hardwood plantations. Many important land use and land cover issues remain unresolved in Australia's rangelands, including questions relating to the optimum grazing pressures, the role of fires in the suppression of unpalatable shrubs and appropriate management strategies for controlling numbers of large kangaroos and rabbits and protecting the natural habitat of threatened species of native animals. The riparian zone, which acts as a crucial buffer between rivers and their catchments, has been one of the most neglected environments in Australia, possibly because river banks, floodplains and wetlands do not fit neatly into the category of land or water. It is widely accepted that the aboriginal peoples must be involved in seeking to achieve the sustainable use of our natural resources. How to achieve the appropriate participation and involvement of aboriginal peoples is a problem that is yet to be fully resolved. In many respects, renewable natural resource systems in Australia are unique. Knowledge creation and application will be a most important resource for the future management of our agricultural forestry and natural resource systems. The solutions to many of the major renewable resource problems do not depend on technology alone. Institutional changes and incentive structures are required that recognize and take account of the pervasive and complex interrelationships between human reactions and responses in their production and consumption activities and the environment.
Understanding farmers' attitudes to land degradation: Some methodological considerations
Authors: Reeve I. J. , Black Alan W.
Published: February 2007

The attitudes of farmers in the New England region of Australia are internally consistent in some cases, but in others seem inconsistent. Cluster analysis and discriminant analysis indicate that even internally inconsistent respondents can be divided into definable categories, and differences in response patterns relate significantly to other variables such as business structure, commodities being produced, attitudes to external influences in decision‐making and to conservation generally. The results suggest that for policy‐oriented research on attitudes to complex environmental issues, analysis should take account of data which do not necessarily conform to the requirements for unidimensional scale construction, but which can usefully be interpreted by analysing respondent clusters.
Evaluation of the characteristics of 14 cover crops used in a soil rehabilitation trial
Authors: Barber R. G. , Navarro F.
Published: February 2007

Many of the soils in Santa Cruz Department, Bolivia, are degraded by serious weed infestation, subsoil compaction, and low organic matter and nitrogen contents. Fallow periods with cover crops are frequently used to recuperate the fertility of degraded soils, but little information exists on the desired characteristics of cover crops for this purpose. The aim of this study was to describe those characteristics, believed to be most relevant to the rehabilitation of degraded soils in Santa Cruz, of 14 cover crops, which included three grasses, nine legumes, and two winter cover crops sown after summer soybean (Glycine max). The cover crop characteristics, evaluated over two years, were ease of establishment, competitiveness against weeds, tolerance to drought, dry matter production and nutrient contents of the above‐and below‐ground residues, nodulation, rooting density and root diameters. The three grasses Tobiata (Panicum maximum var. Tobiatd), Centenario (Panicum maximum var. Centenario) and Brizantha (Brachiaria brizantha) appeared to be the most promising for increasing soil organic matter contents, and the three grasses and groundnuts (Arachis hypogaea)/pigeon pea (Cajanus cajan) for the recuperation of subsoil structure. Mucuna deeringiana and Lablab (Dolichos lablab) were the most promising for increasing soil N status. All of these cover crops competed successfully with weeds.
Application of spectral mixture modelling to the regional assessment of land degradation: A case study from basilicata, Italy
Authors: Zhou X. , Folving S.
Published: February 2007

Mapping and monitoring of land degradation processes such as soil erosion has become an important task for both agricultural and environmental planners. The potential of using SPOT‐HRV data for assessing the types of soil erosion and land degradation is obvious. The spectral information and the spatial resolution of the multispectral data allow a high accuracy in local mapping and rapid regional assessment.

In Basilicata, southern Italy, spectral mixture modelling (end‐member techniques) has been applied to extract relevant information for assessing soil erosion. This method allows an estimate of the proportion of surface cover types (end‐members) within the pixel. From the data sets average spectral responses were extracted for growing vegetation, non‐green sclerophylous vegetation mixed with dry grasses and bare soil. Using these spectra as end‐members in the model, it was possible to decompose the spectral information of all pixels into the three surface components, giving the percentage cover of the three types within every pixel. Classification of the pixels according to the percentage of surface cover or bare soil allows an assessment of erosion or erosion risk.