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1.
Limestone caves are an important scientific and recreational resource in Britain. During the mid- to late 1970s, cavers and
statutory conservation bodies cooperated in a review of cave resources which resulted in the designation of 48 caves or cave
areas as Sites of Special Scientific Interest (SSSI). During the same period, the Wildlife and Countryside Act 1981 was introduced
to provide more effective planning controls on activities such as agriculture carried out within SSSI boundaries. In one case,
at Priddy in the Mendip Hills of Somerset, landowners prevented access to a number of caves in protest over the new, tougher
restrictions on agriculture. Faced with the closure, and perceiving that their recreational use of caves might also be controlled,
local cavers joined the landowners in opposing the proposals for SSSI designation. As a result the proposals were reviewed,
three caves were excluded from the site and controls on the remaining area were relaxed. The case emphasized a need for an
effective system to take account of all factors affecting cave conservation, a need which has led to a more constructive dialogue
between nature conservation bodies, caver organizations and other interested parties.
Received: 1 June 1995 · Accepted: 4 December 1995 相似文献
2.
Conservation tillage and input use 总被引:1,自引:0,他引:1
N. D. Uri 《Environmental Geology》1997,29(3-4):188-201
There continues to be a question as to the overall effectiveness of conservation tillage practices in reducing the impact
of agricultural production on the environment. While it is generally recognized that water runoff and soil erosion will decline
further, as tillage and mulch tillage systems are not used more extensively on cropland, what will happen to pesticide and
fertilizer use remains uncertain. To gain some insight into this, the conservation tillage adoption decision is modelled.
On the assumption that the decision to adopt conservation tillage is a two-step procedure, the first decision is whether or
not to adopt a conservation tillage production system and the second concerns the extent to which conservation tillage should
be used – appropriate models of the Cragg and Heckman (dominance) type are estimated. Based on farm-level data on corn production
in the United States for 1987, the profile of a farm on which conservation tillage was adopted is that the cropland had above-average
slope and experienced above-average rainfall, the farm was a cash grain enterprise, and it had an above-average expenditure
on pesticides and a below-average expenditure on fuel and custom pesticide applications. Additionally, for a farm adopting
a no-tillage production practice, an above-average expenditure was made on fertilizer.
Received: 18 September 1995 · Accepted: 6 December 1995 相似文献
3.
The Environmental benefits and costs of conservation tillage 总被引:1,自引:0,他引:1
Every production practice, including conservation tillage, has positive or negative environmental consequences that may involve
air, land, water, and/or the health and ecological status of wildlife. The negative impacts associated with agricultural production,
and the use of conventional tillage systems in particular, include soil erosion, energy use, leaching and runoff of agricultural
chemicals, and carbon emissions. Several of these impacts are quantified. The conclusions suggest that the use of conservation
tillage does result in less of an adverse impact on the environment from agricultural production than does conventional tillage
by reducing surface water runoff and wind erosion. Additionally, wildlife habitat will be enhanced to some extent with the
adoption of conservation tillage and the benefits to be gained from carbon sequestration will depend on the soil remaining
undisturbed. Finally, further expansion of conservation tillage on highly erodible land will unquestionably result in an increase
in social benefits, but the expected gains will be modest. 相似文献
4.
N. D. Uri 《Environmental Geology》2000,39(3-4):238-248
The economic benefits of the adoption of conservation tillage depend on site-specific factors including soil characteristics,
local climatic conditions, cropping patterns, and other attributes of the overall farming operation. While it is possible
to draw some general inferences about components of economic returns and costs, a comprehensive assessment of the net private
benefits from greater use of conservation tillage is not feasible.
Received: 4 December 1997 · Accepted: 30 March 1998 相似文献
5.
A model for the conservation of geological remains as documents 总被引:1,自引:0,他引:1
Geological remains are conserved mainly either together with living beings for the sake of the integrity of nature or for
their economical or aesthetic value. However, they also have scientific value for the geologist to reconstruct the earth's
past. For this reason we propose a model which is an application of marginal utility theory in economics and takes into account
the informational utility of geological remains. Informational utility of geological remains ranges over their geological significance which is induced by the importance of the geological processes that produce them, and over their spatial extensiveness. Our model takes into account also the cost and budget of conservation and proposes to solve the differential equations of informational utility and cost simultaneously in order
to obtain the optimum quantity of the remains to be conserved.
Received: 9 January 1998 · Accepted: 4 February 1998 相似文献
6.
Wen-yuan Huang Russ W. Keim Yao-chi Lu N. D. Uri Terry Kelley 《Environmental Geology》1998,34(2-3):116-127
The economic and environmental consequences of soil nitrogen tests can have significant impacts on agricultural production.
Some of these are explored here. The pre-side-dress soil N-test is evaluated for a hypothetical farmer growing corn at the
ARS Sustainable Agriculture Demonstration Farm site in southern Maryland. For a farmer not currently using a soil N-test,
adoption of this technology can lead to the enhancement of net farm income and the reduction in nitrogen loss to the environment.
This will transpire only if the farmer is currently underestimating nitrogen carryover by more than 25% or applying nitrogen
fertilizer based solely on an expected plateau-yield goal.
Received: 13 February 1997 · Accepted: 13 May 1997 相似文献
7.
The effect of distribution of iron-oxyhydroxide grain coatings on the transport of bacterial cells in porous media 总被引:3,自引:0,他引:3
E. P. Knapp Janet S. Herman George M. Hornberger Aaron L. Mills 《Environmental Geology》1998,33(4):243-248
Among the demonstrated processes influencing the transport of bacteria through aquifers, the deposition of cells on mineral
surfaces is one of the most important. For example, understanding the transport of introduced bacteria through aquifers is
essential to designing some in situ bioremediation schemes. The impact of the presence and distribution of Fe(III)-oxyhydroxide-coated
sand grains on bacterial transport through porous media was evaluated in column experiments in which bacteria (short rods;
1.2 μm length) were eluted through columns of quartz sand (0.5–0.6 mm in diameter) for several conditions of chemical heterogeneity
of mineral substrate. Fe(III)-oxyhydroxide-coated sand was present as 10% of the mass, and it was arranged in three treatments:
(1) homogeneously distributed, and present as a discrete layer (2) at the top and (3) at the bottom of 14-cm-long sand columns.
A pulse input of 108 cells ml–1 was introduced in an artificial groundwater solution flowing at 14 cm h–1 through the column, and eluted cells were counted. Peak breakthrough occurred at 1.0 pore volume. A large proportion of cells
were retained; 14.7–15.8% of the cells were recovered after three pore volumes of solution had eluted through clean quartz
sand, and only 2.1–4.0% were recovered from the Fe(III)-oxyhydroxide-coated sand mixtures. The three physical arrangements
of the chemical heterogeneity resulted in essentially the same breakthrough of cells, indicating that the spatial distribution
of iron coating does not affect the transport of bacteria. The results of the column transport experiments, which mimic hydrogeological
conditions encountered in field problems, are consistent with our mechanistic understanding of bacterial sorption.
Received: 10 April 1996 · Accepted: 17 February 1997 相似文献
8.
A nitrogen isotope study of soil water and groundwater in southern Indiana, USA, in 1991–1992 demonstrated considerable variations
in nitrate degradation processes compared to an earlier investigation in 1986–1987. Although N-fertilizers were applied in
May 1991, the δ15N values in soil water decreased in February 1992, indicating its delayed release into the system after substantial rainfall.
The δ15N values of groundwater decreased from +12.3‰ in November 1991 to +11.3‰ in February 1992, and to +7.5‰ in March 1992. The
increased residence time of nitrate in the soil resulted in increased denitrification, ammonia volatilization and plant uptake,
and reduced threat to the groundwater quality. The 1986–1987 study in the area reported that excessive rainfall during the
summer rapidly transported the nitrate to deeper horizons and drastically reduced volatilization and microbial reduction of
nitrate, thus increasing the immediate threat to the groundwater quality in the area. The present study demonstrated that
nitrogen isotopic signatures can be used to determine the effects of local soil type, rainfall, and land-use practices on
the fate of nitrate in the subsurface.
Received: 18 February 1997 · Accepted: 17 June 1997 相似文献
9.
King Talal Dam (KTD) watershed is the most important one in Jordan. At its outlet lies the KTD (80 MCM capacity) which serves
irrigation purposes in the Jordan Valley. However, the dam suffers from accelerated annual sedimentation. Therefore, this
study is directed to assess the erosion risk over the watershed, and to simulate actual annual sediment yield at the dam in
order to devise the appropriate conservation practices. Generalized assessment was first conducted over the watershed on the
basis of drainage texture, rainfall erosion index (R), and the ratio p2/P. As a result, the watershed is divided into zones of severe, high (gullying), high (overland flow) and low erosion risk.
Sediment yield at the dam was evaluated by a simulation model. For model validation the simulation results were compared to
the measured values over 12 years period, and a good agreement was obtained in some of the years. The simulation results allow
us to assess the application of two practical conservation practices: terracing and plantation of trees.
Received: 18 November 1997 · Accepted: 18 May 1998 相似文献
10.
E. A. Kalinichenko A. S. Litovchenko A. M. Kalinichenko N. N. Bagmut N. T. Dekhtyaruk 《Physics and Chemistry of Minerals》1997,24(7):520-527
Dehydroxylation of muscovite in the form of small lamellae at 923 <T <1173 K was studied by Electron Spin Resonance (ESR) on Fe3+. The kinetics of the process has been established to be described by the model of continuous nucleation on the large surface
planes of the small plates. Determined by experimental data the rate constant of the process k is shown to be that of dehydroxylation itself. The activation energy obtained by data at T<1100 K is 97.5 KJ·mol−1. The nonlinear dependence of ln(k) on 1/T is explained by the theory of transitions induced by the fluctuative preparation of a potential barrier as a result of thermal
oscillations of ions in the lattice. At high temperatures the potential curve of the hydroxyl's proton is transformed so that
it can overcome the barrier from one potential well to the other (from one hydroxyl site to the adjacent one). Such transformations
of the curve can be caused by the oscillations of large structural clusters (∼1·10−22 kg) with the frequency ∼4.5·1012 s−1.
Received: 3 August 1995 / Accepted: 13 April 1997 相似文献
11.
Landslides are a recognized but poorly studied phenomena in the eastern footslopes of the Aberdare ranges in central Kenya.
The Aberdare ranges traverse the Murang'a, Kiambu, Nyeri and Nyandarua districts of Kenya where fatal landslides have occurred
in the past. A detailed study of a major landslide which occurred at Maringa village in Murang'a district on 30 April 1997,
has been undertaken. The landslide buried three houses at the toe of a slope and killed all the 11 occupants in their sleep.
It is shown that the geology and climate of the study area contribute to the prevalence of landslides not only in Murang'a
but in all the andosol-covered areas throughout the eastern footslopes of Aberdare ranges. Rapid weathering of pyroclastic
rocks in a warm and wet climate create a regolith which is generally weaker than the underlying better-cemented basalt and
basaltic agglomerates. The landsliding occurred when the weathered pyroclastic regolith become saturated after a heavy rainstorm
on high mechanically unstable slope which slid over the more stable basalts. Over-saturation of clay soils (andosol) which
were also derived from weathering of pyroclastic rocks contributed to the slope failure. The results of the study show that
besides fatalities and injuries, the landslide destroyed homes, plantations and roads.
Received: 16 March 1998 · Accepted: 22 September 1998 相似文献
12.
Charles W. Rovey II. 《Hydrogeology Journal》1998,6(2):216-225
Measured hydraulic conductivity increases with the scale of testing, but the reason for this increase is not clear. Possibly,
high-conductivity heterogeneities are more effective in raising hydraulic conductivity over the regional scale than at the
local scale. Alternatively, borehole skin and storage effects, among others, can systematically bias the results of small-scale
tests; thus, the increase may simply be an artifact of the test method.
Radial-flow tests were simulated at various scales in digital models of fractured double-porosity media. The mean hydraulic
conductivity increases until the radius of influence in the test exceeds the fracture spacing. Therefore, under radial flow,
hydraulic conductivity is indeed dependent on measurement scale.
The increase in hydraulic conductivity with scale is a natural consequence of heterogeneity. Over short distances, water converging
toward a borehole must generally flow across heterogeneities. Therefore, small-scale tests tend to measure a weighted harmonic
mean of the hydraulic-conductivity field. Over a large area, however, flow is primarily along high-conductivity heterogeneities.
Therefore, large-scale tests approach a weighted arithmetic mean where high-conductivity heterogeneities have a greater influence.
Received, April 1997 Revised, January 1998 Accepted, December 1997 相似文献
13.
J. G. Zötl 《Environmental Geology》1997,29(3-4):176-187
Some years ago the thermal water wells of the spa Deutsch-Altenburg were considered the result of a local water circulation.
Extensive measurements of the water chemistry, trace elements, and environmental isotopes combined with drillings in the river
bed of the Danube resulted in the indication of a key position of the mineral thermal wells of Deutsch-Altenburg for the groundwater
circulation in the entire Vienna basin. The proof of this fact demanded the inclusion of the complicated geological position
of the basin into the argumentation.
The historical background of Bad Deutsch-Altenburg is the Roman municipium Carnuntum. During the reign of the Roman emperor
Marc Aurel (161-180 A.C.) Carnuntum became the largest Roman municipium northeast of Rome with about 50 000 inhabitants covering
the areas of present-day villages Petronell and Deutsch-Altenburg due to its strategic and trade position. The town was totally
destroyed during the era of "migration of nations." The land surface was farmland or meadows. The first document concerning
the thermal water of Deutsch-Altenburg is an expertise of the medical faculty of the University of Vienna (1548). During the
siege of Vienna by the Turkish army under Kara Mustafa (1683–84) Deutsch-Altenburg was again, destroyed. It was only at the
end of the 19th century that the modern installation of the spa began. The healing thermal water with the highest content
of sulfur in Austria made Deutsch-Altenburg one of the most well-known spas in the country. The archaeological excavation
of Carnuntum is the largest in Austria.
Received: 6 October 1995 · Accepted: 13 November 1995 相似文献
14.
A. B. Klimchouk 《Environmental Geology》1997,31(1-2):1-20
Most of exogeneous epigenetic sulfur deposits are clearly associated with intensely karstified carbonate and sulfate rocks.
This paper demonstrates, using the Pre-Carpathian region as an example, that karstification is one of the most important processes
controlling the formation of sulfur deposits. This is determined by a coincidence of some major prerequisites of these two
processes.
In the Podol'sky and Bukovinsky regions the Miocene aquifer system is well drained by erosion valleys; the giant network caves
known here in gypsum formed under past artesian conditions. In the region of sulfur deposits, associated with the same karstified
gypsum strata, true artesian conditions still prevail. Hydrogeologic data show that abundant cavities detected in the vicinity
of sulfur deposits can be interpreted as having the same origin as the fossil caves of the Podol'sky and Bukovinsky regions.
The current widespread belief that the gypsum/anhydrite stratum in the region is aquifuge separating the Miocene aguifers
is inadequate. This belief caused much controversy with regard to the genetic interpretations of sulfur deposits in the region.
Caves formed by the upward water flow through the gypsum/anhydrite stratum govern the water exchange between the aquifers
within the aquifer system.
A new karst model for the formation of sulfur deposits is suggested. It agrees well with the hydrogeological features of the
Miocene sequence and with biogeochemical mechanisms of sulfur origin in low-temperature diagenetic environments.
Received: 16 February 1995 · Accepted: 4 June 1996 相似文献
15.
The electrical conductivity of San Carlos olivine has been measured at 1100 °C under reducing conditions at controlled oxygen
fugacity, inside and outside the olivine stability field, in order to study the kinetics of olivine destabilization. Electrical
conductivity increases along the direction [010] and decreases along [001]. as oxygen fugacity decreases. To understand these
dependences, electrical conductivity transitory regimes were studied. In response to decreases in oxygen fugacity, two transient
regimes with different time scales have been observed. A fast (≈1–2 min) increase of electrical conductivity is first observed,
followed by a slower decrease (1–10 h, depending on the crystal orientation). After a few hours of annealing, precipitation
of metallic iron and nickel and formation of amorphous silica can be observed at the crystal surface. The fast conductivity
increase in the first transient regime is ascribed to an increase in the population of electrons at the olivine surface. Two
effects: (1) equilibration of surface defects with the bulk of the crystal, and (2) iron loss from the olivine due to metal
precipitation, could explain the subsequent decrease of electrical conductivity. Anisotropic diffusion of surface defects
to the bulk of the crystal, by a process faster than atomic diffusion is the most likely.
Received: 3 September 1997 / Revised, accepted: 16 April 1998 相似文献
16.
Noel D. Uri 《Environmental Geology》2000,40(1-2):41-52
Increase in the use of conservation practices by agriculture in the United States will enhance soil organic carbon and potentially
increase carbon sequestration. This, in turn, will decrease the net emission of carbon dioxide. A number of studies exist
that calibrate the contribution of various individual, site-specific conservation practices on changes in soil organic carbon.
There is a general absence, however, of a comprehensive effort to measure objectively the contribution of these practices
including conservation tillage, the Conservation Reserve Program, and conservation buffer strips to an change in soil organic
carbon. This paper fills that void. After recounting the evolution of the use of the various conservation practices, it is
estimated that organic carbon in the soil in 1998 in the United States attributable to these practices was about 12.2 million
metric tons. By 2008, there will be an increase of about 25%. Given that there is a significant potential for conservation
practices, which could lead to an increase in carbon sequestration, there are a number of policy options that can be pursued.
These include education and technical assistance, financial assistance, research and development, land retirement, and regulation
and taxes.
Received: 27 December 1999 · Accepted: 14 March 2000 相似文献
17.
C. E. Brown 《Environmental Geology》1995,26(4):220-231
The purpose of this report is to describe the research programs and program activities of the US Department of Energy (DOE) that most directly relate to topics in the field of environmental geology. In this light, the mission of the DOE and the definition of environmental geology will be discussed. In a broad sense, environmental geology is that branch of earth science that emphasizes the entire spectrum of human interactions with the physical environment that include environmental health, mineral exploration and exploitation, waste management, energy use and conservation, global change, environmental law, natural and man-made hazard assessment, and land-use planning. A large number of research, development, and demonstration programs are under DOE's administration and guidance that directly or indirectly relate to topics in environmental geology. The primary mission of the DOE is to contribute to the welfare of the nation by providing the scientific foundation, technology, policy, and institutional leadership necessary to achieve efficiency in energy use, diversity in energy sources, a more productive and competitive economy, improved environmental quality, and a secure national defense. The research and development funding effort has most recently been redirected toward greater utilization of clean fossil fuels, especially natural gas, weatherization, renewable energy, energy efficiency, fusion energy, and high-energy physics. This paper will summarize the role that environmental geology has played and will continue to play in the execution of DOE's mission and the energy options that DOE has investigated closely. The specific options are those that center around energy choices, such as alternative-fueled transportation, building technologies, energy-efficient lighting, and clean energy. 相似文献
18.
H. Elhatip 《Environmental Geology》1997,31(1-2):27-33
The carbonate rocks of Turkey, which underlie about one third of the country, possess major water resources with great potential
for electricity generation and water supplies. The ongoing development of karst features, especially in the southern part
of Turkey, demonstrates specific environmental problems that occur in many karst water supply projects. Karst aquifers, springs,
sinkholes, dolines, poljes and other karst features are of great importance from the standpoint of karst water resources and
environmental research studies. In karst regions, conservation and protection of groundwater resources for both qualitative
and quantitative evaluations is possible only when the catchment area is determined accurately. Since the catchment area in
karst terrains is not limited by the surface drainage boundaries and the groundwater flows through well-developed coduits
or fissures, the equations used in non-karstic areas cannot be applied to such karstic regions. Studies on the development
of karst features and its environmental impacts in Turkey are of recent origin. Therefore, many unreliable methods are being
applied in karstic areas. For example, the use of "shallow holes or sinkholes and fault zones" for septic water waste disposal
or as sewage by those who are not familiar with karst, sometimes causes very serious problems of extensive groundwater pollution.
This paper discusses the development of different karstic features in Turkey and case studies on its environmental impacts.
Received: 27 December 1995 · Accepted: 10 July 1996 相似文献
19.
The impact of incorrectly estimating factor productivity in agriculture on the environment and human health 总被引:3,自引:0,他引:3
This paper explores the implications of a misspecification of the production function on the use of factor inputs in the
context of the adoption of an alternative production practice (a technological innovation) designed to mitigate the impact
of agricultural production on human health and the environment. It is demonstrated that if the level of the use of some inputs
is considered rather than their consumptive use (i.e., the actual amount used by a plant), the productivity of the input is
inaccurately measured. It is also demonstrated that an aggregate production function approach can lead to overestimation of
the value of the marginal product of an input due to the frequently implicit assumptions that the output supply, output demand,
and fertilizer demand are infinitely price elastic. The implications of the results are important for determining the optimal
use of inputs such as fertilizer and pesticides which have known adverse impacts on the environment and human health.
Received: 22 November 1996 · Accepted: 4 May 1998 相似文献
20.
A large-scale linear programming model has been designed to assist in the analysis of world-wide energy resource development and processing activities over a 20- to 30-year time horizon. the model includes explicit representation of exploration and production operations for the energy minerals, as well as the supply, conversion, and distribution of the different energy forms, accounting for interfuel substitution alternatives. The method of analysis consists of developing optimal planning solutions relative to anticipated demands for energy and using these solutions as bases for evaluation of energy policies and technology assumptions. This paper briefly outlines the representation of the exploration activities in the overall model formulation and illustrates the projected energy supply patterns and related economics as developed with the model for alternative assumptions about oil resources, exploration success rates, and constraints on exploratory drilling.This paper was presented at Symposium 116.3, Quantitative Strategy for Exploration, held as part of the 25th International Geological Congress, Sydney, Australia, August 1976. 相似文献