排序方式: 共有45条查询结果,搜索用时 15 毫秒
11.
Extrapolating simulations of bioenergy crop agro-ecosystems beyond data-rich sites requires biophysically accurate ecosystem models and careful estimation of model parameters not available in the literature. To increase biophysical accuracy we added C4 perennial grass functionality and agricultural practices to the Biome-BGC (BioGeochemical Cycles) ecosystem model. This new model, Agro-BGC, includes enzyme-driven C4 photosynthesis, individual live and dead leaf, stem, and root carbon and nitrogen pools, separate senescence and litter fall processes, fruit growth, optional annual seeding, flood irrigation, a growing degree day phenology with a killing frost option, and a disturbance handler that simulates nitrogen fertilization, harvest, fire, and incremental irrigation. To obtain spatially generalizable vegetation parameters we used a numerical method to optimize five unavailable parameters for Panicum virgatum (switchgrass) using biomass yield data from three sites: Mead, Nebraska, Rockspring, Pennsylvania, and Mandan, North Dakota. We then verified simulated switchgrass yields at three independent sites in Illinois (IL). Agro-BGC is more accurate than Biome-BGC in representing the physiology and dynamics of C4 grass and management practices associated with agro-ecosystems. The simulated two-year average mature yields with single-site Rockspring optimization have Root Mean Square Errors (RMSE) of 70, 152, and 162 and biases of 43, −87, 156 g carbon m−2 for Shabbona, Urbana, and Simpson IL, respectively. The simulated annual yields in June, August, October, December, and February have RMSEs of 114, 390, and 185 and biases of −19, −258, and 147 g carbon m−2 for Shabbona, Urbana, and Simpson IL, respectively. These RMSE and bias values are all within the largest 90% confidence interval around respective IL site measurements. Twenty-four of twenty-six simulated annual yields with Rockspring optimization are within 95% confidence intervals of Illinois site measurements during the mature fourth and fifth years of growth. Ten of eleven simulated two-year average mature yields with Rockspring optimization are within 65% confidence intervals of Illinois site measurements and the eleventh is within the 95% confidence interval. Rockspring optimized Agro-BGC achieves accuracies comparable to those of two previously published models: Agricultural Land Management Alternatives with Numerical Assessment Criteria (ALMANAC) and Integrated Farm System Model (IFSM). Agro-BGC suffers from static vegetation parameters that can change seasonally and as plants age. Using mature plant data for optimization mitigates this deficiency. Our results suggest that a multi-site optimization scheme using mature plant data from more sites would be adequate for generating spatially generalizable vegetation parameters for simulating mature bioenergy crop agro-ecosystems with Agro-BGC. 相似文献
12.
Vittorio Barale 《Journal of Coastal Conservation》2010,14(4):317-326
The ecosystem approach requires that all elements of an ecosystem, and their mutual interactions, be taken into consideration
in any management effort. The selection of suitable geographical units, where this approach can be taken, requires the assessment
of ecological provinces, characterized by a coherent set of environmental traits. The marine side of coastal zones, where
the interaction between atmosphere, land and sea is not bounded by evident geographic markers, represents a critical factor
in this assessment. A coastal province can be defined by physical setting, but also by its bio-geo-chemical features, ideally
on the basis of synoptic remote sensing data, collected at space/time scales not accessible by other means. Classifications
based on indicators such as temperature, wind speed and chlorophyll-like pigments, demonstrate the identification of potential
ecological provinces in the Mediterranean Sea. The results suggest remote sensing as the ideal tool to set up the basis for
an ecosystem approach to the management of each province. 相似文献
13.
The performance of different policy design strategies is a key issue in evaluating programmes for water quality improvement
under the Water Framework Directive (60/2000). This issue is emphasised by information asymmetries between regulator and agents.
Using an economic model under asymmetric information, the aim of this paper is to compare the cost-effectiveness of selected
methods of designing payments to farmers in order to reduce nitrogen pollution in agriculture. A principal-agent model is
used, based on profit functions generated through farm-level linear programming. This allows a comparison of flat rate payments
and a menu of contracts developed through mechanism design. The model is tested in an area of Emilia Romagna (Italy) in two
policy contexts: Agenda 2000 and the 2003 Common Agricultural Policy (CAP) reform. The results show that different policy
design options lead to differences in policy costs as great as 200–400%, with clear advantages for the menu of contracts.
However, different policy scenarios may strongly affect such differences. Hence, the paper calls for greater attention to
the interplay between CAP scenarios and water quality measures. 相似文献
14.
15.
Outstanding features of Mediterranean forest area are highlighted with a special reference to biodiversity and connections with forest management. The naturally originated and anthropogenic progress of the mosaic-like evolution, as well as the man-induced factors and natural constraints are described. The past and present close linkages between management and biodiversity are then analysed by means of a few, outstanding cases typical of the geographical region. The management shift on increasing economically marginal forest area (abandonment) appears to be the major force currently driving connections with inherent and associated biodiversity. The goals following the new-established environmental roles of forests have shifted towards adaptive management, namely the implementation of locally tailored rules in accordance with prominent forest functions. Key priorities to face up to the new scenarios are then discussed.Economic and policy implications are addressed with reference to multipurpose forestry and the related annual flow of outputs. It is shown the role of water-related services, as well the provision of various non-wood forest products and public goods in addition to wood and other traditional forest outputs. Reference is also made to the dualism between the Northern and the South-Eastern Mediterranean countries due to different level of economic development (and pressure of forest resources) together with very different institutional structures, i.e. public ownership in Southern and South-Eastern Mediterranean countries. Nevertheless, the situation is going to become more harmonious in the medium run by growing economic development, the affirmation of local rights on forest resources, globalisation and, above all, rural out migration and exchanges of peoples confirming the traditional role of the Mediterranean Region at cross road of South-North and Eastern-Western cultures. 相似文献
16.
Chiesa M Rigoni F Paderno M Borghetti P Gagliotti G Bertoni M Ballarin Denti A Schiavina L Goldoni A Sangaletti L 《Journal of environmental monitoring : JEM》2012,14(6):1565-1575
The present study is focused on the implementation of a novel, low cost, urban grid of nanostructured chemresistor gas sensors for ammonia concentration ([NH(3)]) monitoring, with NH(3) being one of the main precursors of secondary fine particulate. Low-cost chemresistor gas sensors based on carbon nanotubes have been developed, their response to [NH(3)] in the 0.17-5.0 ppm range has been tested, and the devices have been properly calibrated under different relative humidity conditions in the 33-63% range. In order to improve the chemresistor selectivity towards [NH(3)], an Expert System, based on fuzzy logic and genetic algorithms, has been developed to extract the atmospheric [NH(3)] (with a sensitivity of a few ppb) from the output signal of a model chemresistor gas sensor exposed to an NO(2), NO(X) and O(3) gas mixture. The concentration of these pollutants that are known to be the most significant interfering compounds during ammonia detection with carbon nanotube gas sensors has been tracked by the ARPA monitoring network in the city of Milan and the historical dataset collected over one year has been used to train the Expert System. 相似文献
17.
We used data from various space-borne sensors to monitor the marine ecosystem in the northwestern Mediterranean Sea, at the
Costa Dorada, between the City of Barcelona and the estuary of the river Ebro. The aim of this study was to demonstrate that
the combination of different remote sensing data (acquired at different electromagnetic frequencies) allows for an improved
monitoring system, in particular for a better monitoring of the marine ecosystem and, hence, a better coastal zone management.
We present remote sensing data acquired by the Synthetic Aperture Radar (SAR) and the Along-Track Scanning Radiometer (ATSR)
aboard the Second European Remote Sensing Satellite (ERS-2), and by the Sea-viewing Wide Field-of-view Sensor (Sea WiFS) on
the SeaStar satellite. By combining the different data we are able to overcome specific drawbacks of the single sensors, like
an insufficient temporal coverage, or a strong dependence on weather and daylight conditions.
Within the study area two main features have been selected as examples, which are well visible on many of the analysed images.
The first one exhibits a higher load of chlorophyll-a and surface-active compounds and a lower sea surface temperature (SST),
which is likely to be caused by the plume of the river Llobregat, southwest of Barcelona. It can clearly be seen from the
imagery how the river plume is driven along the coast by the local currents. The second feature can be related to cooling
water being released from a nuclear power plant and causing turbulence in the water body, which in turn gives rise to signatures
visible on the ERS-SAR imagery. 相似文献
18.
Maritime spatial planning: opportunities &; challenges in the framework of the EU integrated maritime policy 总被引:1,自引:0,他引:1
In recent years, maritime spatial planning (MSP) has become an internationally emerging, promising tool for the implementation
of integrated ocean management. MSP provides the appropriate framework for public authorities and stakeholders to coordinate
their action across sectors and administrative boundaries, and to optimize the use of natural resources. In November 2008
the European Commission adopted the Communication “Roadmap for Maritime Spatial Planning: Achieving Common Principles in the
EU” (COM(2008) 791 final) aiming to facilitate the development of MSP by Member States and to stimulate its implementation
at national and EU level. Core element of this Roadmap is a set of ten key principles for MSP in Europe. Although endorsed
as valid and comprehensive, further discussion and research is needed to identify challenges, measures and tools for the key
principle’s practical application. This special issue of the Journal of Coastal Conservation: Planning and Management (JCCPM)
seeks to contribute to this discussion. Its purpose is to shed light from different angles on the various aspects of the mentioned
ten key principles and provide lessons learned from experience in different maritime areas around the world. Taking a more
scientific, rather than a political point of view, the following articles will debate the different principles, their practical
handling, as well as the consequences linked to their application. 相似文献
19.
Mykhaylo Yatsyshyn Ivan Saldan Chiara Milanese Viktoriia Makogon Alberto Zeffiro Vittorio Bellani Rosadele Di Lorenzo Pacifico Cofrancesco Alessandro Girella Daniele Dondi Oleksandr Reshetnyak Sergiy Korniy 《Journal of Polymers and the Environment》2016,24(3):196-205
Hybrid composite made of glauconite and polyaniline was prepared in aqueous solution of citric acid. Scanning electron microscopy combined with energy dispersive X-ray analysis shows uniform aggregates made of glauconite microparticles and polyaniline matrix. The results of X-ray powder diffraction suggest that: (1) citric acid used for the polymerisation of aniline causes formation of emeraldine salt where macromolecular ordering in the amorphous polymer takes place; (2) no chemical interaction between glauconite and emeraldine takes place in the prepared composite. FT-IR spectra of the prepared polymer and composite show features indicating all the functional groups that are present in the diiminoquinone–diaminobenzene state of polyaniline. Thermal stability of the composite was higher than the prepared polymer suggesting the occurrence of an interphase interaction between glauconite and emeraldine. After pyrolysis in purified nitrogen the composite still remained glauconite, and ε-Fe3N together with amorphous and graphitic carbon were found as reaction products. The values of electrical conductivity and magnetization of the composite suggest that optimization of these values might be achieved based upon the relationship between glauconite and polyaniline. 相似文献
20.
Annamaria Costa Claudia Gusmara Davide Gardoni Mauro Zaninelli Fulvia Tambone Vittorio Sala Marcella Guarino 《Environmental science and pollution research international》2017,24(31):24135-24146
The aim of this experimental study was to evaluate the influence of anaerobic digestion and storage on indicator microorganisms in swine and dairy excreta. Samples were collected every 90 days for 15 months at eight farms, four pig, and four dairy farms, four of them having a biogas plant. Moreover, to evaluate storage effects on samples, 20 l of manure and slurry taken at each farm (digested manure only in farms with a biogas plant) were stored in a controlled climatic chamber at 18 °C, for 6 months. The bacterial load and the chemical-physical characteristics of excreta were evaluated at each sampling time, stored slurry, and manure were sampled and analyzed every 2 months. A high variability of the concentration of bacteria in the different excreta types was observed during the experiment, mainly depending on the type and time of treatment. No sample revealed either the presence of Escherichia coli O157:H7 or of Salmonella, usually linked to the temporary rearing of infected animals in facilities. Anaerobic digestion and storage affected in a significant way the reduction of indicator bacteria like lactobacilli, coliforms, and streptococci. Anaerobic digestion lowered coliforms in pig slurry (? 2.80 log, P < 0.05), streptococci in dairy manure (? 2.44 log, P < 0.001) and in pig slurry (? 1.43 log, P < 0.05), and lactobacilli in pig slurry (? 3.03 log, P < 0.05). Storage lowered coliforms and the other indicators counts, in particular in fresh wastes, while clostridia did not show a reduction in concentration. 相似文献