bluuebunny/crossref_metadata_2025_split huggingface dataset:
Trends in natural resource use and prospects for sustainable resource management in Kenya's Arid and Semiarid Lands
Authors: Darkoh M. B. K. 
Published: February 2007

AbstractThis paper describes the environmental problems facing the development of Kenya's Arid and Semiarid lands (ASAL) today. The problems arise because of a rapidly declining resource base in the ASAL as a result of overexploitation and misuse, following basic land use conflicts. The extent of the overutilization or resource damage is not well known and varies a great deal from one agroecological zone to another and from resource to resource in the ASAL; those most affected include: soil, water, range, forest, livestock and wildlife. As a result of increased population growth in the ASAL, these resources are under stress. This paper argues that many of the environmental problems in the ASAL cannot be solved if the development programme does not address the needs of the people who live in the ASAL. There is a need to shift the objective of ASAL development from a preoccupation with economic growth and the idea that the ASAL should make a contribution to GNP through interregional trade and export to sustainable development that enables the communities in the ASAL to support themselves at as good a standard of living as possible. The last part of this paper outlines a strategy to promote such sustainable development.
Amelioration of a calcareous saline‐sodic soil by gypsum and forage plants
Authors: Ahmad N. , Qureshi R. H. , Qadir M. 
Published: February 2007

AbstractA field experiment was carried out at the University of Agriculture, Faisalabad (Pakistan) during 1988–90 to evaluate the comparative efficiency of chemical and biological methods for the reclamation of a calcareous saline‐sodic soil (pHspHs = pH of saturated soil paste
= 8.2–8.6; ECeECe = Electrical conductivity of the saturation extract
= 7.4–9.0 dS m−1; SARSAR = Sodium adsorption ratio
= 55.6–73.0 for upper 30 cm layer). Five treatments were assessed, three involved cropping: sesbania (Sesbania aculeata), sordan (Sorghum bicolor x Sorghum sudanese), and kallar grass (Leptochola fusca) and two were non‐cropped (control and gypsum at 100.0 per cent GR‐15·0 cm) were employed. Water of low electrolyte concentration (EC = 0.27 dS m−1) was used for irrigation and leaching. Sesbania and kallar grass were found to be effective biotic materials for soil reclamation. These plant species produced substantial biomass and also improved the soil environment by lowering the EC and SAR of the soil. Sordan was relatively less‐effective due to its sensitivity to high temperature and sodicity during germination and early seedling stages. After two cropping seasons, wheat (cultivar LU 26S) was sown as a test crop. Efficiency of treatments as indicated by wheat grain yield was in the order: sesbania = gypsum > kallar grass > sordan > control.
Deforestation trends in the Atlantic Zone of Costa Rica: A case study
Authors: Veldkamp E. , Weitz A. M. , Staritsky I. G. , Huising E. J. 
Published: February 2007

AbstractIn this study we have tried to link a quantitative inventory of deforestation to possible factors driving forest clearing, like accessibility and soil quality. The Study Area covered 395 km2 in the Atlantic Zone of Costa Rica. Basic information came from aerial photographs taken in 1952, 1960, 1971 to 73, 1981 and 1984. Photo interpretations were digitized and processed with the help of a monoplotting programme. Three phases in deforestation were distinguished:

The period before 1960, characterized by a gradual increase in the rate of deforestation, with preferential clearing along rivers and on fertile soils.
The period 1960‐1972. This period shows an increased clearing rate caused by a new centre of colonization, Cariari. Furthermore, banana plantations entered the area and main roads were constructed. Deforestation took place preferentially along roads and on fertile soils.
In the period 1972‐1984 the remaining forest ‘islands’ were cleared at an accelerated rate. This was because only small areas of forest were left by this period. Also between 1972 and 1984 the fertile soils were cleared most rapidly.
Effects of controlled grazing on a degraded dwarf shrub, annual grass semidesert vegetation type of northwestern Kenya
Authors: Oba G. 
Published: February 2007

AbstractA degraded dwarf shrub, annual grass semidesert vegetation type in Turkana, northwestern Kenya, was protected from livestock grazing from October 1985 to December 1990. The effects of controlled grazing on plant cover, litter cover and bare ground were monitored to appraise the trend in range condition using grazed transects (GT) and ungrazed transects (UGT). Despite an initial increase, plant cover on the UGT deteriorated in a similar manner to that on the GT. At the conclusion of six years of protection, the cumulative mortality of Indigofera cliffordiana on the UGT exceeded 60 per cent whereas on the GT it was 6 per cent. Furthermore the density of I. cliffordiana on the protected area decreased whereas that on the GT remained substantially unchanged. Aristida mutabilis replaced I. cliffordiana on the UGT but showed little change on the grazed area. Sedera hirsuta disappeared from the GT. On the UGT the percentage of bare ground, despite an initial decline (39.3 ± 7.3 per cent), increased substantially (68.9 ± 15.7 per cent) in parallel with the GT (77.3 ± 4.7 per cent). The results contradict a commonly held view that land degradation only occurs when plants are overused. The findings suggest that degradation can occur in the absence of grazing, especially if the plant species involved are dependent on perturbation. As over‐resting eliminates I. cliffordiana, it seems judicious to allow a 2‐3 year deferral period followed by moderate grazing if it is to be optimally managed.
Impact of protection and free grazing on sand dune vegetation in the Rajasthan Desert, India
Authors: Kumar M. , Bhandari M. M. 
Published: February 2007

AbstractIn the Thar (Rajasthan) Desert of India, sand dunes and sandy plains dominate the landscape. Livestock raising and marginal land cultivation are the main occupations. Owing to the high growth rates of human and livestock populations and a decrease in pasture area and its primary productivity, these lands bear acute grazing pressure. Average rainfall is low and vegetation growth is restricted to the short rainy season of two to four months duration. Often there are years of lower than normal rainfall. In these circumstances, fenced areas, established to stabilize formerly active sand dunes, are increasingly opened to grazing to prevent high stock mortality during droughts. This study was conducted in four fenced and one open site, representative of the region's different vegetation types and grazing pressures. The impact of 2 and 5 per cent free grazing pressure on protected sand dune vegetation density and cover was tested in the two fenced sites. The vegetation data for grazed sites are compared with those for the two ungrazed fenced (protected) and one unfenced (open) site subjected to unlimited grazing pressure throughout the year. The vegetation sampling was carried out by the qaudrat and line‐transect method before and after grazing from November 1984 to October 1986. It shows a significant reduction in the density and cover of many palatable species and an increase of unpalatable plants. The effect of vegetation degradation is greater in the unfenced area. The low grazing pressure on the fenced sand dunes sites can still cause drastic changes in the vegetation density and cover. Protection resulted in reduced sand erosion and enhanced growth of palatable plants in the fenced sites under similar climatic and edaphic conditions to the unfenced sites. The grazing pressure in the unfenced areas remains high to extreme during the year, due to low land productivity and high feed demand. The regeneration rate is very slow under the constant (3rd to 5th degree) overgrazing. Low intensity grazing pressure on the fenced sites during droughts can cause heavy utilization and mortality of palatable vegetation.
Frentes de trabalho: Potentials and limitations of large scale labour employment for soil and water conservation in Cape Verde
Authors: Haagsma B. , Reij C. 
Published: February 2007

AbstractAfter gaining independence in 1975 the government of Cape Verde embarked on large scale nationwide employment schemes to carry out soil and water conservation, (SWC) work. Impressive numbers of erosion control schemes have been realized on a scale not seen in other Sahelian countries. the programmes have largely concentrated on mechanical protection and afforestation. Little is known about the impact of these massive SWC activities on agricultural production. Employment has been created by establishing workgangs (frentes de trabalho), which became an important source of income, in particular for the numerous landless peope. These frentes have become institutionalized, and at present their role is increasingly under criticism. Serious problems have arisen with regard to the participation of local land users in the management of natural resources. the consensus now is that local land users should be given greater responsibilities for resource management, supported, where necessary, by the state. However, The role of frentes can be cut back only gradually due to the lack of viable employment alternatives in other sectors of the economy.
Establishment of trees on mixtures of pulverized fuel ASH and Gypsum. I. Tree performance
Authors: Moffat A. J. , Shaw P. J. A. 
Published: February 2007

AbstractExperiments that investigated the performance of nine tree species planted in pulverized fuel ash (PFA) and gypsum power stattion wastes are described. Lombardy and white poplars, common alder and false acacia were the most successful in gypsum and PFA‐gypsum mixtures, but tree growth in pure PFA was unsatisfactory. Co‐disposal of gypsum and PFA is the best means of promoting the growth of tolerant species planted in power station wastes. Tree performance is improved if these materials are covered by a soil layer, which promotes tree rooting into the underlying wastes.
Modifications of the phosphorus cycle with development of lignite mine soils
Authors: Trasar‐Cepeda M. C. , De Blas E. , Garcia‐Rodeja I. , Leirós M. C. , Gil‐Sotres F. 
Published: February 2007

AbstractVarious aspects of the P cycle in four and seven year old soils from the Meirama lignite mine (northwest Spain) were studied. With increasing soil age, The organic P (Po) content increased in parallel with the organic matter content. the observed increase in secondary inorganic P (Bic—Pi + NaOH‐Pi + us‐NaOH Pi) is related to the increase in the retention capacity for P with soil age. the observed increase in the HCl‐P fraction can be attributed to a gradual dissolution of the non‐extractable forms of P produced from fertilizers added in the course of spoil management. Both the C:Po ratio and phosphatase activity also increased with soil age, suggesting that biochemical mineralization processes are taking place and indicating a need for the hydrolysis of phosphate esters to ensure an adequate phosphorus supply to plants. All these findings suggest that in the long term plants May, suffer a pronounced P deficiency.
Determining the extent and spectral separability of industrially despoiled land in South Wales from satellite sensor data
Authors: Foody G. M. , Cutler M. E. 
Published: February 2007

AbstractSatellite remote sensing offers the potential to accurately identify and monitor spectrally separable land‐cover classes at a range of spatial and temporal scales. This paper investigates the separability of despoiled land in imagery acquired by sensors carried by the Landsat satellites. These systems offer the opportunity to map areas at large to medium scales at a relatively high temporal frequency and so provide information on environmental quality necessary for many monitoring and planning activities. From an investigation using imagery of South Wales it was found that despoiled land was separable from other classes in the Landsat TM imagery, with an accuracy of over 90 per cent. Furthermore, with Landsat TM data three spectral wavebands were found to provide a level of separability similar to that based on all wavebands available, illustrating potential savings to the analyst. Despoiled land cover was classified from Landsat TM and MSS data and these classifications were evaluated against a manually produced map of despoiled land cover derived from the interpretation of aerial photographs. Estimates of the extent of despoiled land cover in administrative units derived from the Landsat TM data were significantly correlated (r = 0.81) with the map based estimates, although a weaker correlation was observed with Landsat MSS data.
Proposed assessment of the vulnerability of European soils to pollution using a soter shell approach
Authors: Batjes N. H. , Van Engelen V. W. P. , Oldeman L. R. 
Published: February 2007

AbstractAfter recent unanticipated occurrences of environmental pollution caused by the time‐delayed and sudden release of contaminants previously believed to be held firmly in soils, awareness has increased that the vulnerability of soils to chemical degradation needs to be assessed and mapped. Although some soils appear to be capable of receiving and holding chemical compounds while at the same time retaining their ecological functions, others are readily damaged. Procedures for identifying areas where vulnerable soils occur are presented, with special reference to the minimum soil data sets that would be required in a small scale study at the European level using geographical information systems. These data can readily be compiled, stored and processed with the relational database management system developed for SOTER, The 1:1 million world soil and terrain digital database project of the International Society of Soil Science, which is co‐ordinated by the International Soil Reference and Information Centre. the proposed initial soil vulnerability programme would essentially serve to increase awareness about areas prone to chemical soil degradation, and will form the basis for implementing soil pollution assessment programmes at larger scales (1:1 M to 1:250 000). the latter national or regional programmes would include the identification of the major sources of soil pollution, and measurement of the accumulated load and the rate of loading according to uniform and standardized procedures, providing the conceptual basis for developing process based models to assess where particular types of soil degradation are likely to occur.
Phosphorus saturation in soils and groundwaters
Authors: Behrendt H. , Boekhold A. 
Published: February 2007

AbstractOn average, crops require about 30 kg ha−1 y−1 of P in humid regions. in some regions fertilizer and manure are applied in amounts that exceed this. the surplus of P in agricultural areas is about 20‐45 kg ha−1 y−1. This implies an accumulation of P. the surplus of P estimated from the balance of agricultural soils of industrialized countries in Europe in the last four decades is between 800 and more than 1500 kg ha−1 although this distribution is not even. Phosphorus accumulation is more than one order of magnitude higher than average in areas with intensive livestock farming. Consequently, The application of high levels of manure exceed the capacity of the soil to store P. This implies that P saturation May, pose a problem. Indeed, about half of the Dutch sandy soils (approximately 300 000 ha) are currently considered to be saturated with P, meaning that there is a hazard of P leaching to groundwaters in the future.Assuming current phosphate application rates, phosphate leaching is a distinct possibility over a period of decades to a century. Vulnerable areas are soils with high inputs, low sorption capacities for P, high water‐tables and a low retention time for water. the possible consequence is a time‐delayed increase of eutrophication of surface waters (lakes, rivers and the sea) caused by a diffuse load of P in the few next decades. Modelling the influence of different agricultural strategies shows that accumulation of P would not increase further only if the use of P increases by an amount that compensates for the increased inputs. It is proposed to change the current support system of agriculture by installing a system of financial incentives and taxes which seek to promote nutrient balances for each farm.
Effects of stopping liming on abandoned agricultural land
Authors: Hesterberg D. 
Published: February 2007

AbstractIt is suggested that stopping liming on agricultural land could lead to a potential chemical time bomb (CTB). the sequence of interrelated events leading to the CTB include the end of liming, perhaps caused by a change in land use, a progressive decrease in soil pH and increased solubility of potentially toxic contaminants that accumulate in soils as a result of agricultural practices. Data are presented on rates of long‐term soil acidification and modelled changes in the solubility of some trace metals in soil as a result of acidification. Soil acidification rates depend primarily on acid input rates and the soil's acid neutralizing capacity, possibly limited by neutralization kinetics. Experimental data illustrating this point show that the pH decreased rapidly in a field soil receiving ammonium rather than nitrate fertilizer treatment. on a limed agricultural field that was later abandoned and converted to deciduous woodland, The pH of the 0‐23 cm soil layers decreased over 100 years from pH 7 to 4.2. Deeper layers acidified at a slower rate. Thermodynamic model calculations simulating the solubilities of metals in a sandy topsoil showed zinc, cadmium and aluminium solubilities increasing exponentially with decreasing pH, resulting in several‐fold solubility increases between pH 5 and 4. These results suggest how metal solubility increases after liming stops. the model pH‐solubility relationships depended on the type of metal, The solid phase controlling the solubility, and the amount of metal in the soil if adsorption controlled the solubility. Decreasing pH and the resultant increase in metal solubility expected on abandoned farmland might be managed through techniques such as liming or planting forests of selected tree species.
Environmental conditions and chemical time bomb hazards in Poland
Authors: Smal H. 
Published: February 2007

AbstractObservations on the state of the environment, soil properties, soil hazards and some possible changes in soil parameters are discussed. Sandy and light loamy soils cover more than 50 per cent of the arable land in Poland. About 58 per cent of soils are acid (pH<5‐5) in the surface layer and 25 per cent in the layer from 100 to 150 cm. About 51‐3 per cent of soils are very vulnerable to pollution. According to a BIGLEB‐SOWEP prognosis, in the year 2000 about 13 per cent of soils will be seriously at risk from chemical degradation. Acidification will proceed due to increases in the emission of SO2 and NOx, and the end of liming. the environmental conditions in Poland favour delayed responses to environmental hazards: chemical time bombs.
Chemical time bombs related to forestry practice: Distribution and behaviour of pollutants in forest soils
Authors: Mayer R. 
Published: February 2007

AbstractHeavy metals and persistent organic pollutants from atmospheric deposition and from fertilizer and pesticide applications are important hazardous substances in forest soils. Data are presented showing that these substances preferentially accumulate in the upper humic horizons of the soils. Another group of substances to be considered in relation to the chemical time bomb concept are the components of humus and soil minerals, mainly nitrogen and metals, which May, be mobilized and thus threaten groundwater quality. Forestry management practices such as thinning, cropping, fertilization and liming are discussed as potential triggers for the mobilization of harmful substances. in this context, The turnover (build‐up and mineralization) of organic matter plays a crucial part. It will be shown, however, that even more danger arises from soil acidification induced by the atmospheric deposition of acidifying pollutants such as sulphates and nitrates.
Riverine and estuarine sedimentation of pollutants and leaks from sludges and wastes: Analytical, prognostic, experimental and remedial approaches
Authors: Förstner U. 
Published: February 2007

AbstractThe effects of chemical time bombs are typically discontinuous and non‐linear. Once a certain threshold has been passed, The system starts to behave differently from before (Stigliani, 1991). a typical example is the consumption of a certain buffer capacity in a system, and the subsequent breakthrough of parameters such as pH values and metal concentrations. the mobilization of metals from different types of waste materials, after the depletion of typical barriers (mechanical or chemical) or after an increase of accelerating factors such as the lowering of pH values, was studied. the release of metals from sediments, leaks of pollutants from sludges and wastes, and some remedial approaches are discussed.
Sediment pollution in the southern baltic
Authors: Lewandowski A. , Szczepanska T. 
Published: February 2007

AbstractIn 1991 geochemical mapping of sediments in the southern Baltic was begun by the Polish Geological Institute, Marine Geology Branch to determine sediment pollution, sediment spreading and the rate of accumulation of pollutants to define ‘hot‐spot’ regions. the initial results on the concentration of heavy metals in 36 samples collected in the Gdansk Basin are presented. One ‘hot‐spot’ is the network of channels in Gdansk Harbour where the bottom sediment (sludge) is highly contaminated. Sampling results and proposals for dredging, separation of the sand fraction, dewatering and the deposition of sludge are discussed.
Sources of heavy metal pollution in the rhine basin
Authors: Rautengarten A. 
Published: February 2007

AbstractThe concept of industrial metabolism is introduced as an analytical framework for many diffuse sources of pollution for which ‘end of pipe’ control will not work and pollution prevention at the source is required. the concept is applied to pollution in the Rhine Basin which ends up in the Netherlands Delta and the North Sea, where the character of the pollutants changes over time. Cadmium, lead and zinc pollution from point sources, traffic, corrosion and atmospheric deposition are considered. Calculations cover the period from 1950 to 2010. in this study strongly urbanized paved and unpaved areas are distinguished based on their transport of pollutants to surface waters.
Low volatile chlorinated hydrocarbons in aquatic sediments in Berlin and surrounding areas
Authors: Terytze K. , Mende W. 
Published: February 2007

AbstractLow volatile chlorinated hydrocarbons, especially DDT and HCH, have been used as indicators of the level of pollution in aquatic sediments. These compounds were present in all the sediment samples analysed in this study by gas chromatography. Enrichment factors between the water and sediment were high (Kd = 85‐108 for DDT), documenting the strong geoaccumulation of toxic chlorinated hydrocarbons. in contrast with the generally held view, no linear relationship was observed between the concentration of HCH and PCBs and the organic matter content of the sediment. the application of the EVOLON model to determine the kinetics of sorption clearly showed a saturation value. the sorbed amount of low volatile chlorinated hydrocarbons depends to a large extent on the amount of organic matter on the surface of the sediment particles.