共查询到20条相似文献,搜索用时 15 毫秒
1.
N. D. Uri 《Environmental Geology》1999,37(1-2):9-18
The impact of energy on the adoption of conservation tillage is of special importance in addressing concerns about the effect
of agricultural production on the environment in the United States. It is the subject of this paper. After establishing that
a relationship exists between the price of energy and the adoption of conservation tillage via cointegration techniques, the
relationship is quantified. It is shown that while the real price of crude oil, the proxy used for the price of energy, does
not affect the rate of adoption of conservation tillage, it does impact the extent to which it is used. Finally, there is
no structural instability in the relationship between the relative use of conservation tillage and the real price of crude
oil over the period 1963–1997.
Received: 6 February 1998 · Accepted: 4 May 1998 相似文献
2.
Environmental considerations in the fertilizer use decision 总被引:1,自引:0,他引:1
Noel D. Uri 《Environmental Geology》1998,34(2-3):103-110
The increase in the use of fertilizer in agricultural production has been associated with a substantial increase in agricultural
productivity in the United States. This increase in fertilizer use has been driven by a variety of economic forces including
variations in the price of output and changing relative factor prices. Associated with the increase in the use of fertilizer
have been adverse environmental consequences that are not reflected in the costs and returns of agricultural production. That
is, externalities exist whose cost need to be internalized. Because the use of fertilizer has been shown to respond to market
forces, it is efficient to use the market to control the use of fertilizer. This can be done through, for example, the use
of a fertilizer tax.
Received: 31 December 1996 · Accepted: 13 May 1997 相似文献
3.
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
4.
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
5.
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
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.
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
8.
J. Pacheco Luis Marín Armando Cabrera Birgit Steinich Oscar Escolero 《Environmental Geology》2001,40(6):708-715
The nitrate concentration in 12 water-supply wells were monitored for the period April 1992 to March 1993. Each water-supply
well was sampled once a month. The nitrate concentrations in the 12 wells ranged from 7 to 156 mg/l. Two water-supply wells
(Chacsinkin and Peto) showed concentrations that reached 3.5 times the maximum permissible limit for the Drinking Water Standard
(45 mg/l). A third water-supply well (Akil) exceeds the norm for 7 out of 12 months. The use of nitrogen-rich fertilizers
are responsible for high nitrate concentrations in groundwater in the southern part of Yucatan, Mexico where intensive agricultural
practices exist.
Received: 14 December 1999 · Accepted: 2 May 2000 相似文献
9.
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
10.
M. F. Abu-Taleb 《Environmental Geology》1999,37(1-2):64-71
When using surface infiltration as a method of recharge, infiltration testing is considered an important additional data
input along with other hydrogeologic data into the recharge decision. As part of an investigation into the potential for groundwater
recharge, two desert basins in Jordan (Wadi Madoneh and Wadi Butum) were investigated to determine the possibility of recharge
using floodwater retention structures. For each area, short-duration (up to 7-h) infiltration tests were conducted to estimate
surface infiltration capacity of the upper soil layers in order to present to the authorities preliminary information which
could be used along with other factors to aid in the selection of the best site for a pilot recharge project. Given the highly
fractured rock formations that constitute the underlying aquifers in the two areas, it was assumed that the upper alluvium
layers are the limiting factors in transmitting water to target aquifers. The infiltration tests conducted to estimate the
recharge characteristics of the recharge sites yielded test results that indicated a representative infiltration rate of 0.44 m/day
for the Wadi Madoneh site and 0.197 m/day for the Wadi Butum site. The data input was used subsequently with other decision
factors to select the most promising site for the pilot project.
Received: 9 January 1998 · Accepted: 27 April 1998 相似文献
11.
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
12.
The environmental impact of agro-export production in developing countries remains an important research topic. The political economy-inspired literature on developing country agro-exports maintains that export crops are pesticide intensive – or, more generally, environmentally destructive – while local and national market crops are less pesticide intensive, or environmentally benign. If used to draw conclusions about the impact of national market versus export market expansion, this view has significant limitations, most importantly the comparison of high-commodity value export crops with low-commodity value crops for national market. To overcome this and other limitations of prior analyses, this paper addresses the question: how does market orientation influence pesticide intensity where the same crops are grown for both the national market and for export? Data from a survey of Costa Rican vegetable farmers are used to compare pesticide intensity of 27 vegetable crops, five of which are produced for both national and export markets. The general pattern that emerges is that national market vegetables are more pesticide intensive than export vegetables in the area. Yet, controlling more for the crop variable is important, and specific comparisons of the five vegetables grown for both markets – carrot, chayote, corn, green beans, and squash – illustrate that market orientation alone does not determine pesticide intensity, but that it is jointly influenced by regulatory risk, crop value, and pest susceptibility, among other factors. Continued attention to both political economy and ecological processes in “second nature” will allow political ecology to make important contributions to understanding pesticide problems and implementing agroecological solutions. 相似文献
13.
A. Pulido-Bosch S. Bensi L. Molina A. Vallejos J. M. Calaforra P. Pulido-Leboeuf 《Environmental Geology》2000,39(7):791-799
Relatively high concentrations of NO3 usually have their origin in processes of organic pollution and excessive use of inorganic fertilizers. In the case of agricultural
areas, these activities may generate great quantities of nitrates. This fact has enabled us to use the nitrate ion to characterize
an exploited aquifer unit of a very complex aquifer system, as is the case for the Campo de Dalías aquifer system (SE Spain).
The shallow boreholes, which draw water from intensively cultivated superficial formations, yield waters with a high NO3 content. When the boreholes are deeper and penetrate low-permeability formations in the superficial layers, the waters contain
little NO3; similar to what happens in areas of recharge where agricultural activities are absent. In addition, using longitudinal sections,
it is possible to demonstrate the possible existence of connections between superficial and deep aquifers using NO3 as a tracer. Similarly one can locate those sectors responsible for contamination caused by the poorly lined boreholes themselves,
when they perforate more than one aquifer in a multiple aquifer formation.
Received: 22 December 1998 · Accepted: 20 March 1999 相似文献
14.
Stephanie Pincetl 《Geoforum》2006,37(2):246-255
The United States is often considered the progenitor of conservation planning in the world, the first to establish a vast public domain, for example. But with continued population growth, conservation planning on private lands—rural and at the urban fringe—continues to be a substantial challenge due to a tradition of local home rule in land use planning and strong private property protection afforded by the US Constitution. New “bottom-up” collaborative approaches, as well as other innovative strategies seem to be emerging. How effective these will be given pressures for growth and high property values remain to be seen without a rethinking of ideas of nature, a rebalancing of the role of property in American local fiscal regimes, and of private property rights. 相似文献
15.
Cover systems are widely used to safeguard landfills and contaminated sites. The evaluation of the water balance is crucial
for the design of landfill covers. The Hydrologic Evaluation of Landfill Performance (HELP) model of the US Environmental
Protection Agency was developed for this purpose. This paper discusses some limitations of version 2 of this model and some
operational difficulties for the use of this model in Germany, which has been developed for the United States. The model results
are tested against field data of the water balance, measured on test fields on the Georgswerder landfill in Hamburg. Theoretically,
HELP considers gravitational forces as driving forces of water flow only. Therefore capillary barriers cannot be simulated.
Furthermore, the formation of and the flow through macropores are not considered, a main critical process that the diminishes
the effectiveness of compacted soil liners. In the output comparison, the matching of measured and simulated data is quite
good for lateral drainage, but failed for surface runoff and liner leakage through compacted soil liners. A further validation
study is planned for HELP version 3 using a broader range of test field data.
Received: 10 January 1995 · Accepted: 14 November 1995 相似文献
16.
Foresighted and determined local authorities, purposeful exploration (i.e. by seismic reflection) and extensive testing led
to the discovery of a substantial groundwater resource near the community of Seon (Switzerland) at a depth of 268–305 m. Production
tests revealed a hydraulic conductivity of ∼5.10–5 m/s, transmissivity of ∼5.10–4 m2/s and a storage coefficient of ∼2% in the aquifer. Pumping up to 1500 l/min is sustainable; the water quality complies chemically
and bacteriologically with drinking-water requirements. The residence time of several 103 years, determined by isotope techniques, guarantees protection from surface contamination. The elevated temperature of 19.5 °C
of the produced water enables combined use for drinking water and space heating. The environmental benefits are substantial:
the emission reduction amounts up to 780 tons/year CO2 and 1 ton/year SO2.
Received: 21 September 1998 · Accepted: 10 February 1999 相似文献
17.
Integrated use of hydrochemistry and resistivity methods in groundwater contamination caused by a recently closed solid waste site 总被引:6,自引:0,他引:6
In order to investigate the groundwater contamination by solid waste disposal using both hydrochemical and geophysical methods,
the Halkalı (I˙stanbul) solid waste disposal site which was closed in 1994 was investigated. The disposal site lies on a ridge
between two valleys filled with alluvium. A total of six boreholes were drilled on two lines across the Menekşe valley adjacent
to the Halkalı site. Groundwater samples collected from these boreholes were analyzed for various contaminant parameters.
The results indicate that TDS and chloride concentrations decrease horizontally away from the waste site whereas they increase
with depth. Electrical soundings carried out at 12 locations yielded high resistivity values at the upstream part of Menekşe
valley while lower values were obtained from the locations near the leachate seepage points.
Received: 11 November 1997 · Accepted: 23 February 1998 相似文献
18.
Humboldt, Arago, and the temperature of groundwater 总被引:1,自引:0,他引:1
Stanley N. Davis 《Hydrogeology Journal》1999,7(5):501-503
19.
Predicting New Hampshire indoor radon concentrations from geologic information and other covariates 总被引:2,自引:2,他引:0
Generalized geologic province information and data on house construction were used to predict indoor radon concentrations
in New Hampshire (NH). A mixed-effects regression model was used to predict the geometric mean (GM) short-term radon concentrations
in 259 NH towns. Bayesian methods were used to avoid over-fitting and to minimize the effects of small sample variation within
towns. Data from a random survey of short-term radon measurements, individual residence building characteristics, along with
geologic unit information, and average surface radium concentration by town, were variables used in the model. Predicted town
GM short-term indoor radon concentrations for detached houses with usable basements range from 34 Bq/m3 (1 pCi/l) to 558 Bq/m3 (15 pCi/l), with uncertainties of about 30%. A geologic province consisting of glacial deposits and marine sediments was
associated with significantly elevated radon levels, after adjustment for radium concentration and building type. Validation
and interpretation of results are discussed.
Received: 20 October 1997 · Accepted: 18 May 1998 相似文献
20.
N. F. Gray 《Environmental Geology》1997,30(1-2):62-71
Work carried out at the abandoned copper (Cu) and sulphur (S) mine at Avoca (south east Ireland) has shown acid mine drainage
(AMD) to be a multi-factor pollutant. It affects aquatic ecosystems by a number of direct and indirect pathways. Major impact
areas are rivers, lakes, estuaries and coastal waters, although AMD affects different aquatic ecosystems in different ways.
Due to its complexity, the impact of AMD is difficult to quantify and predict, especially in riverine systems. Pollutional
effects of AMD are complex but can be categorized as (a) metal toxicity, (b) sedimentation processes, (c) acidity, and (d)
salinization. Remediation of such impacts requires a systems management approach which is outlined. A number of working procedures
which have been developed to characterise AMD sites, to produce surface water quality management plans, and to remediate mine
sites and AMD are all discussed.
Received: 16 January 1996 · Accepted: 5 March 1996 相似文献