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INTRODUCTION The insoluble phosphates which can not be directly absorbed by plants are the mai forms of inorganic phosphate in soil. These kinds of phosphates can be solubilized by several species of bacteria which are widely spread in soil especially in rhizosphere where70% of the bacteria are capable of solubilizing inorganic phosphate.  相似文献   

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Transnational land deals are among the most contested but inadequately understood topics. In this paper, we focus on the features of large‐scale transnational land deals (LSTLDs) in the Global South through an examination of Ethiopia. We apply a mixed method (qualitative and quantitative) research design.Results indicate that in 2005–2015, the government leased nearly 2·47 million ha of the country's approximate total 114 million ha area and offered 11·5 million ha of cultivable land to domestic and transnational investors. We explore the prevalence of LSTLDs deals by companies of the Global South, particularly entrepreneurs from India. Ethiopia's example validates emerging arguments on the rise of South–South investment deals rather than the established explanation of North–South capital flows. However, 75% of the land deals show poor performance. The study shows that LSTLDs have contributed to raising domestic agricultural production but have resulted in non‐performing loans of the banks of the host country. In sum, the land deals have resulted in financial grabbing, where Ethiopian banks end up with non‐performing loans and then must chase investors to settle the approximate €791 million in loans that investors borrowed for their projects. Copyright © 2017 John Wiley & Sons, Ltd.  相似文献   

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Purpose

Black carbon (BC) refers to solid charred residues produced by the incomplete combustion of fossil fuels and biomass. The Great Hinggan Mountains are located on the margin of the East Asian monsoon region, and BC from fossil fuel sources could be deposited in this region through transport by westerlies and the monsoon. The overall objective of this study was to evaluate the sources and intensity of BC deposited during the last 150 years in the Great Hinggan Mountains, Northeast China.

Materials and methods

BC concentrations, stable carbon isotope values of BC (δ13C-BC), and charcoal counts in the Motianling (MP2) peatland were measured in this study. BC values measured via the chemical method were regarded as total BC concentrations, and the BC values measured via the microscope method (i.e., charcoal) represent BC from biomass burning.

Results and discussion

The results showed that BC in MP2 peatland was mainly produced from local fire events before the 1930s. After the 1930s, with the increase in European fossil fuel BC emissions, the BC produced by fossil fuels became the major BC sources in the MP2 peatland, and the total BC fluxes in the MP2 peatland were much higher than those before the 1930s. With the decrease in European BC emissions and increase in Chinese BC emissions after the 1970s, the BC emitted by China became the major fossil fuel BC source in the MP2 peatland. However, the implementation of environmentally friendly policies decreased the BC emissions from fire events, leading to the gradual decrease in BC depositional fluxes in recent years.

Conclusions

In recent years, fossil fuels remain the major sources of BC, but the implementation of environmentally friendly policies has decreased fossil fuel BC emissions, leading to the gradual decrease in BC depositional fluxes in the Great Hinggan Mountains.
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Eurasian Soil Science - Data on concentrations and distribution of tritium in soils of the “Atomic” Lake excavation explosion area of Semipalatinsk Nuclear Test Site (Kazakhstan, East...  相似文献   

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The IUCN is the leading authority on assessing species’ extinction risks worldwide and introduced the use of quantitative criteria for the compilation of Red Lists of threatened species. Recently, we assessed the threat status of the 483 European butterfly species, using semi-quantitative data on changes in distribution and in population sizes provided by national butterfly experts. We corrected distribution trends for the observation that coarse-scale grid cells underestimate actual population trends by 35%. To account for uncertainty, we included a 5% error margin on the distribution and population trends provided. The new Red List of European butterflies determined one species as Regionally Extinct, 37 species as threatened (Critically Endangered, Endangered or Vulnerable) and a further 44 as Near Threatened. The use of semi-quantitative data on distribution and population trends permitted us to use IUCN criteria to compile a scientifically underpinned Red List of butterflies in Europe. However, a comparison of detailed monitoring data for some grassland species showed that coarse-scale grid cell data and population trends strongly underestimate extinction risks, and the list should be taken as a conservative estimate of threat. Finally, combining the new Red List status with the data provided by the national butterfly experts, allowed us to determine simple criteria to delineate conservation priorities for butterflies in Europe, so called SPecies of European conservation Concern (SPEC’s). Using European butterflies, our approach illustrated how Red Listing can be performed when data are incomplete for some IUCN criteria or vary strongly among countries.  相似文献   

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Soil subsidence has become a critical problem since the onset of drainage of the organic soils in the Everglades Agricultural Area (EAA), which may impair current land uses in the future. The objectives of this study were to characterize soil microbial community‐level physiology profiles, extracellular enzymatic activities, microbial biomass, and nutrient pools for four land uses: sugarcane, turfgrass, pasture, and forest. Long‐term cultivation and management significantly altered the distribution and cycling of nutrients and microbial community composition and activity in the EAA, especially for sugarcane and turf fields. The least‐managed fields under pasture had the lowest microbial biomass and phosphorus (P) levels. Turf and forest had more microbial metabolic diversity than pasture or the most intensively managed sugarcane fields. Land‐use changes from sugarcane cropping to turf increased microbial activity and organic‐matter decomposition rates, indicating that changes from agricultural to urban land uses may further contribute to soil subsidence.  相似文献   

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In the course of germplasm exploratory work, a strain of a False Horn plantain cultivar was found which produced two bunches at fruiting. Cropping of the suckers of this material through three cycles showed that all the plants studied, produced two bunches of fruits. The results suggest that this plantain tentatively designated as double bunch, is of genetic origin arising probably from a mutation of the existing plantain cultivar. The implications for the identification of genetic diversity as well as for the evaluation and conservation of genetic resources are discussed.  相似文献   

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A long-term hydrological and water chemistry research was conducted in three experimental microbasins differing in land cover: (1) a purely agricultural fertilized microbasin, (2) a forested microbasin dominated by Carpinus betulus (European hornbeam), and (3) a forested microbasin dominated by Picea abies (L.) (Norway spruce). The dissolved inorganic nitrogen (DIN: NH 4 + , NO 2 ? , NO 3 ? ) budget was examined for a period of 3 years (1991–1993). Mean annual loads of DIN along with sulfate SO 4 2? and base cations Ca2+, Mg2+, Na+, K+, and HCO 3 ? were calculated from ion concentrations measured in stream water, open-area rainfall, throughfall (under tree canopy), and streamwater at the outlets from the microbasins. Comparison of the net imported/exported loads showed that the amount of NO 3 ? leached from the agricultural microbasin is ~3.7 times higher (43.57 kg ha?1?a?1) than that from the spruce dominated microbasin (11.86 kg ha?1?a?1), which is a markedly higher export of NO 3 ? compared to the hornbeam dominated site. Our analyses showed that land cover (tree species) and land use practices (fertilization in agriculture) may actively affect the retention and export of nutrients from the microbasins, and have a pronounce impact on the quality of streamwater. Sulfate export exceeded atmospheric rainfall inputs (measured as wet deposition) in all three microbasins, suggesting an additional dry depositions of SO 4 2? and geologic weathering.  相似文献   

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Land use and soil cover patterns of arable lands in Balakhna district of Nizhny Novgorod gubernia in the last quarter of the 18th century and in the middle of the 19th century were studied with the use of the General Land Survey plan of Balakhna district (scale 1 : 84000), the map of Nizhny Novgorod gubernia by Mende (scale 1 : 42000), and the State Soil Map (scale 1 : 1 M). The data obtained attested to a steady and considerable decrease in the plowed area during that period. According to the historical materials, at the end of the 18th century, plowland occupied about 1290 km2, or 32% of the entire district (4200 km2). In the middle of the 19th century, the plowed area decreased to about 990 km2 (25%). According to the modern statistical data on land use in Balakhna district (within its boundaries of the 18th–19th centuries), the area of plowed fields is less than 700 km2 (18%). This means that at least 14% of the study area is occupied by the postagrogenic soils. If we take the plowed area of the district in the 18th century for 100%, we can conclude that more than 40% of formerly plowed lands have been transformed into long-term fallows. The absolute predomination of soddy-podzolic soils (Retisols) is typical of the soil cover of Balakhna district. In the course of the reduction of the plowland area from the end of the 18th century to the middle of the 19th century, the percent of different soils composing this area did not change much. In general, the impact of soil quality on the decrease in the plowland area in that period is not observed.  相似文献   

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It has been assumed that marine habitats and resources, especially, are almost unlimited, and that if one habitat became degraded or a particular fisheries resource depleted, there always would be another to replace it. Therefore, natural resource management principals are beginning to include human motivation and responses as part of the marine and coastal systems that are being studied and managed. Managers of marine resources face the challenge of balancing conservation and development objectives in the context of the inherent uncertainty of natural systems and the political and social pressures of human systems. Natural resource managers, scientists and the general public seem to share a vision for the future as a world in which societal and economic decisions will be strongly coupled with an increasingly comprehensive understanding of the environment. This in turn will lead to both socio-economic health and ecosystem health. A paradigm shift is being seen in the evolution of the role of scientists in society from simply observers of the natural world with tenuous linkages to resource managers and the public, to partners in modern society's quest for answers to pressing questions related to sustainable use and conservation of natural resources. A US Agency for International Development supported, joint effort between the US National Oceanic and Atmospheric Administration, the Government of Israel and the Hashemite Kingdom of Jordan to conduct a comprehensive research and monitoring program directed at the new Binational Red Sea Marine Pearce Park will be a pioneering effort to employ and test this new paradigm.  相似文献   

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Agricultural land use in the area of the post-Chernobyl Plavsk radioactive hotspot (Tula region, Central Russia) has raised a problem of radioecological safety of obtained plant foodstuff. Verification of 137Cs activities and inventories in components of “soil-plant” systems of the territory has been conducted in 2014–2017 in 10 agrosystems and 2 semi-natural meadows. It was revealed that density of 137Cs contamination of arable chernozems and alluvial calcareous soils nowadays varies in a range 140–220 kBq/m2 and exceeds radiation safety standard by ˜ 3.5–6 times. Deep plowing of the arable soils up to 30-cm in 1986–1987 resulted in decreasing of 137Cs inventories in rooting zone by ≈ 70% for crops cultivated with shallow disk plowing (wheat, barley), and by ≈ 35% for crops cultivated with middle plowing (buckwheat, amaranth, white mustard). The investigated plants and their compartments can be grouped on the basis of transfer factor values as follows: maize (stems and leaves) > amaranth > bromegrass > vegetation of dry meadow, galega, sunflower (seeds), vegetation of wet meadow > maize (grain), soybean (pods), barley (grain), buckwheat (grain), potatoes (tubers) > white mustard (seeds), wheat (grain). It is noticeable that generative plant compartments are characterized by less 137Cs activities in comparison with stems and leaves; and that 137Cs root uptake is not coincide with total flux of mineral nutrients in “soil-plant” systems. In sum, 137Cs soil-to-plant transfer in the area of the Plavsk radioactive hotspot is characterized by considerable discrimination, so 137Cs activities in plants are completely in accordance with national standards.  相似文献   

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G.G. Beckmann 《Geoderma》1975,13(4):299-315
The concept of the “standard cell” of a rock, which compares numbers of cations associated with 160 oxygen ions (Barth, 1948) can be applied to the solid material of soils and saprolites as a means of tracing changes in element content at different depths in soil profiles weathered from igneous rocks. The “standard cells” can be derived readily from total silicate analyses of rock and soil materials and can be expressed as chemical formulae or in tables to facilitate comparisons. Standard cells for several layers from each of three profiles from southeast Queensland illustrate the type of information obtained. Standard cells of solum and weathered rock layers of a profile previously studied by mineralogical techniques permit a comparison of inferences about weathering which have been drawn by the two approaches.  相似文献   

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Twenty years ago, Desender and Turin (1989) analysed the changes in the composition of carabid beetles in four NW European countries between the periods <1950 and 1950-1985. Recently, a new distribution atlas of carabid beetles in Belgium was compiled using data collected during the period 1986-2008. In the light of the Countdown2010 target of halting the loss of biodiversity, we used these new data to test whether or not previously observed trends were altered. Since 1950, 46 species were no longer recorded in Belgium and seven species were added to the Belgian fauna. By relating the changes in distribution area to ecological and life history traits as well as to conservation priorities of the species, we examined which species characteristics were associated with the strongest changes in distribution. Comparing the period before 1950 with the period 1950-1985 showed that species from nutrient-poor dry biotopes and heathlands, threatened, rare and big species declined. Generalists, non-threatened species, species with a pan-European distribution range, species in the centre of their distribution range and common species, on the other hand, increased. From the period 1950-1985 to 1986-2008, mainly macropterous species, both rare and very common species and big species decreased, while generalists, dimorphic species, species with a pan-European distribution range and species that were already common in the second period increased. For the conservation of carabid beetles in a strongly industrialised and highly fragmented NW European landscape, we propose actions on two levels: first, the protection and adequate management of high quality biotopes, especially nutrient-poor grasslands and heathlands, in large core areas for specialist species and second, the creation and/or restoration of a ‘matrix’ that facilitates the exchange of individuals between core areas for the conservation of both generalist and specialist species.  相似文献   

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