共查询到20条相似文献，搜索用时 328 毫秒
1.
Antonio Augusto Rossotto Ioris 《GeoJournal》2018,83(1):61-72
The intricacies of one of the most relevant agribusiness frontiers in the world today—the north of the State of Mato Grosso, in the southern section of the Amazon, Brazil—are considered through a critical examination of place-making. Vast areas of Amazon rainforest and savannah vegetation were converted there, since the 1970s, into places of intensive soybean farming, basically to fulfil exogenous demands for land and agriculture production. The present assessment goes beyond the configuration of new places at the agricultural frontier, and starts with a qualitative intellectual jump: from place-making on the frontier to place-making as an ontological frontier in itself. It means that, instead of merely studying the frontier as a constellation of interconnected places, we examine the politicised genesis of the emerging places and their trajectory under fierce socio-ecological disputes. The consideration of almost five decades of intense historic-geographical change reveals an intriguing dialectics of displacement (of previous socio-ecological systems, particularly affecting squatters and indigenous groups, in order to create opportunities for migrants and companies), replacement (of the majority of disadvantaged farmers and poor migrants, leading to land concentration, widespread financialisation and the decisive influence of transnational corporations) and misplacement (which is the synthesis of displacement and replacement, demonstrated by mounting risks and a pervasive sentiment of maelstrom). Overall, there was nothing inevitable in the process of rural and regional development, but the problems, conflicts and injustices that characterise its turbulent geographical trajectory were all more or less visible from the outset. 相似文献
2.
David Carr 《Geoforum》2006,37(1):94-103
Agricultural frontiers are hot spots for the most dramatic land cover change in the history of humankind: forest conversion to agriculture. They are also areas of unusually rapid population growth and acute poverty, with scant access to public services and infrastructure. Although a large body of literature explores the determinants of land cover change on the frontier, one issue that has been largely unstudied is that of frontier political and socio-economic development. This paper reports on data from 28 communities along an agricultural frontier in a core conservation zone of the Maya Biosphere Reserve (MBR), where the predominant land tenure systems at the community level appear to be related not only to land use, but also to political organization and human development indicators. 相似文献
3.
This paper explores the adjustments that residents in one part of the High Plains prefer in coping with the depletion of the Ogallala aquifer. The authors identify 31 possible adjustment policies and report on public preferences, examining differences among socioeconomic groups and also the preferred governmental agencies to administer specific programs. Adjustments involving improved water use efficiency were most favored; those entailing financial incentives were least liked. The local groundwater management district was the preferred agency overall. Most significant differences in preference were between those in agribusiness and those outside agriculture. 相似文献
4.
The main pioneer frontier considered by geographers is the Amazonian pioneer frontier. The occupation of the Brazilian territory has been carried out through successive economic cycles. Currently, the expansion of soybean crops in Amazonia is considered as the last economic cycle involving new migrations to still unexplored areas. Mapping this frontier is necessary in order to better understand its drivers and think about efficient land use policies to struggle its progress. In this paper, we propose an innovative methodology for mapping the agricultural frontier in the Amazonian state of Mato Grosso (Brazil) using satellite data acquired during the 2000–2006 period. We assume that the frontier evolves through successive land-use stages such as wildlands, non-croplands, extensive croplands and intensive croplands areas. The transitions between two stages can then be monitored through land-use change analysis. A particular emphasis is given on three land-use transitions named “deforestation”, “economic” and “intensification sub-frontiers”. In order to adapt this model for the use of remote sensing data, we defined (1) a relevant spatial scale corresponding to an agrarian locality, (2) relevant indices to qualify the land-use types and (3) rules applied on land-use types to define the frontier’s location. Our results highlight the dynamic of the agricultural frontier towards northern areas. We identified four main agricultural regions with different levels of agricultural intensification. We finally discuss these results with respect to governmental policies and economics for a better understanding of the frontier’s dynamic. 相似文献
5.
本文报道了平坝白云岩风化剖面风化前缘稀土元素超常规富集(总量达3%以上)现象及其特征,并通过主元素、稀土元素的测定,结合白云岩中“酸不溶物”的提取和代表性样品的化学淋溶实验研究,讨论了白云岩风化壳剖面稀土元素的分异特征,认为风化前缘稀土元素的富集是由3方面的因素共同作用造成的:1)对白云岩风化残积的继承;2)剖面上部一部分轻稀土淋滤聚积;3)碳酸盐岩中非均匀分布的原生含磷矿物风化产生的稀土磷酸盐矿物的聚集,后者是最重要的原因。 相似文献
6.
Hydrogeology and sustainable agriculture 总被引：3，自引：0，他引：3
C. R. Aldwell 《Environmental Geology》1997,32(2):93-99
The world's population continues to grow and to require more and more food. Attempts by modern high output agriculture to
meet this need have led to serious environmental problems. A more sustainable balance is now required and is being sought
in a variety of ways. Hydrogeologists should continue to highlight the threat posed by agriculture to groundwater, particularly
since groundwater is a hidden resource and its degradation and rehabilitation often take place slowly. But the time has come
for groundwater specialists to go further and become actively involved in helping to provide practical and sustainable solutions.
The agriculture of the future requires a holistic approach which balances the essential economics of food production with
equally valid environmental needs, including those of groundwater. Such an approach demands cross-sectoral collaboration involving
multidisciplinary research and action within an integrated policy framework. This paper reviews the current groundwater/agriculture
interface and some of the attempts being made to achieve a more truly sustainable agriculture with particular emphasis on
European experience. It aims to stimulate greater interest and involvement by hydrogeologists in helping to bring about realistic
solutions that will enable future generations to enjoy adequate good quality food and water.
Received: 9 August 1996 / Accepted: 11 November 1996 相似文献
7.
《Geoforum》2015
This article examines the dynamics of double exposure, vulnerability, and resistance to neoliberal globalization and environmental change in the Chilean agricultural region of Biobio. By using climatic models and secondary Agricultural Census data from 1997 and 2007, we assess how Chilean neoliberal reforms have, since 1974, facilitated land use changes and forestry investments. We demonstrate that policy changes which incentivize forestry investments have reduced cultivated agricultural lands and native forest, and concentrated land in the hands of global agribusiness corporations. Compounding these issues, Biobio shows a climatic trend towards aridity coupled with an increasing demand for irrigation. Analyzing these conditions, we argue that the neoliberal globalization of regional agriculture under the context of climatic changes has produced a regional space of increasing vulnerabilities and uneven geographical development in Biobio. We particularly demonstrate that the Chilean mode of agricultural neoliberalization has been conducive to land dispossession—to the detriment of traditional agriculture —and has homogenized the biophysical landscape, replacing traditional crops and native forests with exotic species like pines and eucalyptus. We also examine how local producers are using resistance movements to cope with and contest neoliberal environmental changes. We conclude by evaluating the implications of these spaces of agricultural vulnerabilities and local resistances in the context of uneven geographical development at a regional and global scale. 相似文献
8.
K. H. Stone Dr. 《GeoJournal》1979,3(6):539-554
In the world of earlier scientists a frontier was an exciting concept, term and line. It is not quite so now. Presently frontiers are zones that are partially settled and with limited transportation. They vary in size but in total area and in location they present significant potentials for population growth absorption. From about 1900 to 1940 frontier development was international and intercontinental in scope; now it is primarily national or regional in scale. Currently about as much of the total area in world frontiers is in stability as in growth and there are considerable areas of decline. The present trend is toward more stability while urbanization is dominating; until these two really change only major military causes will produce notable variations in frontier use while individual national political policies will result in local geographical pulses of minor advances and retreats. Yet, there is much potential area for new food production and settling, the world is still largely in a growth syndrome, and there are alternatives that also should be considered. 相似文献
9.
近期国内珠宝市场上出现一种产自巴西的绿欧泊,该类绿欧泊表现出的宝石矿物学特征与传统的欧泊有着明显差异。采用常规宝石学测试手段,并结合电子探针、X射线粉末衍射、扫描电子显微镜、红外吸收光谱、紫外吸收光谱等测试分析方法,就其化学成分、物相、微结构、谱学特征及颜色成因等问题展开初步研究。结果表明,巴西绿欧泊的主要矿物组成为蛋白石,含不等量的α-方石英和α-鳞石英等次要矿物,整体呈不规则胶柬状结构,局部微波纹理发育;该类欧泊主要由直径约10～30nm的SiO2球粒聚集而成;由H2O和M—OH倍频振动致近红外吸收谱带位于7000cm-1处,由H2O合频振动致近红外吸收谱带分别位于5200,5612cm叫处,由M—OH与[SiO4]合频振动致近红外吸收谱带位于4600-4100cm-1范围内。笔者还对巴西绿欧泊的呈色机理一并给予了探讨。 相似文献
10.
Poverty tourism: theoretical reflections and empirical findings regarding an extraordinary form of tourism 总被引：1，自引：0，他引：1
Manfred Rolfes 《GeoJournal》2010,75(5):421-442
During the mid-1990s, a new form of tourism was established in metropolises of several developing countries or emerging nations. This type of tourism consists in visits to the most disadvantaged parts of the respective city. Poverty tours or slum tours
are offered on a relatively large scale in the South African cities of Johannesburg and Cape Town, Rio de Janeiro in Brazil,
as well as in Indian metropolises, to name some important examples. The target group of these tours consists primarily of
international tourists. It is estimated that 40,000 such tourists visit favelas in Rio de Janeiro each year, around 300,000
the townships in Cape Town. This contribution refers to and comments on these developments and insights regarding poverty
tourism or slumming, based on empirical research and experiences in South Africa, Brazil, and India. It will be shed light
on the phenomenon from an observational-theoretical perspective. It is aimed to open a discussion on the ways poverty tours
or slumming observes and simultaneously programmatically charges poverty. And, it will be considered in which way poverty
tourism is observed. 相似文献
11.
《地学前缘(英文版)》2020,11(6):2141-2156
The rare earth elements and high-field-strength elements (REE-HFSE) exploration sector conducts most evaluations at deposit and smaller scales. It is not evident how the sector performs a preceding exploration stage—rating and prioritising REE-HFSE mineralised provinces—to determine which provinces are prospective enough to warrant investment. Here we present an objective, repeatable, low-cost method to screen any REE-HFSE province, as a foundation for district-scale investigations or asset evaluations. It is original for REE-HFSE screening, and adapted from regional scale copper, cobalt and petroleum exploration, and CO2 storage, screening methods. It is centred upon a mineralised province’s favourability for potential value creation, and to identify: (a) its main information gaps; (b) its weakest links; (c) its exploration maturity and remaining potential category; (d) how it compares against other REE-HFSE provinces; and (e) if further investigation is justified. This method incorporates geoscience, strategy, economic and socio-environmental factors in a way that is understandable and directly usable across stakeholder groups. The workflow is systematic, yet flexible enough to accommodate organisation-specific criteria, and usable for other commodities. It provides the platform to build a global REE-HFSE province map and database consistently across national boundaries and organisations. Categories for the extent of province exploration maturity and remaining mineral potential are proposed. We illustrate the applicability of these methods using the Gardar REE-HFSE Province (GRHP) of south Greenland. We conclude that it is a moderate size, frontier province that is currently of questionable favourability for value creation. To move GRHP into a positive favourability class, its current weak links need strengthening by research, government policy and industry stakeholders: evaluate the mineral system; integrate all information geospatially and place it in the public domain; help the region improve some community health and safety issues; convert some mineral resources into an Ore Reserves category; commence mining and sales production. 相似文献
12.
金刚石产地来源的确定是国际性难题,其中由于砂矿金刚石可能存在搬运过程的混合,其产地来源的确定更加具有争议性。巴西金刚石绝大部分来源于砂矿,从成矿地质背景、形貌和颜色、内部结构、矿物包裹体、微量元素、C同位素组成分布等六个要素总结分析了巴西金刚石研究的相关成果,为国际砂矿来源金刚石产地辨识提供参考。研究结果显示,巴西大部分矿区金刚石的特征与世界范围其它矿区的相似,以橄榄岩型为主,难以相互区分。但其中Juina地区和Machado河产地的金刚石具有独特的氮含量（无氮的Ⅱ型为主）和聚集状态,内部结构、矿物包裹体组合及温压环境特征均显示出深部地幔来源的特点,和巴西其它产地具有一定的区分度。与世界范围不同产地砂矿来源金刚石的基本特征对比显示,不同国家具体地区砂矿金刚石在上述不同要素的组合上存在一定的差异性,但总体上要借助现有资料进行产地来源的准确判断还非常困难,需要进行更深入细致的工作。 相似文献
13.
Portions of two Geosat-ERM altimeter tracks and corresponding suborbital shipboard gravity and bathymetry profiles in the South Atlantic Ocean were analyzed: one across the Walvis Ridge (about 1100 km long) and the other in the Brazil Basin (about 2300 km long). Together, these profiles sample those types of sea-floor topography which dominate the gravity signature at wavelengths of 20 to 300 km. The Walvis Ridge is a massive aseismic ridge and the Brazil Basin profile crosses both an old seamount (emplaced at the time the crust was young) and a very young mid-plate volcano. Both profiles cross fracture zones. After the gravity and bathymetry profiles were split into subprofiles, various cross-spectral characteristics could be determined by FFT techniques. Analysis showed that observed admittance is not well constrained by either an Airy-type or flexural compensation models across the Walvis Ridge, but those over the Brazil Basin can be readily explained by an Airy-type model with a mean crustal thickness of about 20 km.
A theoretical filter was then designed, based on a priori geological knowledge, and used to predict bathymetry from the high-passed gravity/geoid anomalies.
Not surprisingly, the predicted bathymetry shows more detailed and correct short-wavelength (20–300 km) features than those predicted from the historical data base, as represented e.g., by the DBDB5 gridded bathymetric model. For areas where historical shipboard bathymetry measurements are widely spaced (longer than about 10 km for single-beam data) but where some regional geologic information is available (such as the relative ages of mid-plate volcanoes and crust), bathymetry predicted from altimetric data can be used to upgrade regional bathymetrie data bases, on which regional geologic/geophysical understanding depends. 相似文献
14.
T. Forster-Carneiro M. D. Berni D. Lachos-Perez I. L. Dorileo M. A. Rostagno 《International Journal of Environmental Science and Technology》2017,14(10):2077-2092
For emerging countries such as Brazil, improved performance in the agricultural sector can be achieved by studies on the factors that have affected the performance and on economic perspectives relative to their internal structure and its relation with the external market. The present work aims to contribute with sustained economic expansion by studying strategies for expanding the energy supply in agribusiness. The characterization of specific energy consumption and energy indicators was performed considering a process of natural evolution, using logistic curves that describe the growth or evolution process. The specific energy consumption in agricultural activities was determined from data on the consumption of energy by machinery and equipments used in agricultural activities, as well as by establishing specific consumption indicators (ratio of energy consumed per unit produced) for each stage of production and by end-use. Nine crops and three herds were evaluated. In conclusions, the technology levels reached by the Brazilian agricultural sector have reflected on increased productivity and competitiveness in the international market with improvement in machines and equipments efficiency and operational capacity. In sugarcane culture, for example, the productivity increased 10% from 2009 to 2015. It has also been noticed a trend to reduce the use of low-power tractors and to increase the use of medium- to high-power tractors, which has also favored the productivity increase. The incorporation of new technologies tends to be more intense in the crops and herds that have an already established market. 相似文献
15.
L. Michael Trapasso 《GeoJournal》1992,26(3):311-322
During the summer of 1989 this author was afforded the opportunity to live and study in Brazil under the auspices of the Fulbright-Hays Commission. Study included extensive travel, visits to universities and research institutes, a lecture series, and interviews with social and physical scientists concerning many aspects of Brazilian life, culture, history and geography. The issue of the deforestation of the Brazilian Amazon was investigated by utilizing all available resources along with Brazilian media presentations, Brazilian publications, and personal observations. This research represents “a” Brazilian perspective. It is neither a series of excurses for the destruction, nor a condonation of the actions that have taken place, but a series of alternative perceptions as seen from within Bazil. Addressing ths complex multifaceted issue brings about a number of interesting perspectives. Those addressed here are: Brazilian government actions, Brazilian research concerning the Amazon, the Amazon as a frontier, the lure of mineral wealth, the “debt for nature” question and environmental martyrdom. Though they may be difficult for the reader to accept, good or bad, there are reasons for the destruction. 相似文献
16.
C. N. Caviedes Dr. 《GeoJournal》1982,6(2):101-109
Traditional natural hazard researchers have failed to deal with hazard occurrences in Latin America in a comprehensive and coherent fashion because of their cultural bias and lack of knowledge about the regional implications of hazard conditions.The attempt is made in this paper to point out that some of the climatic hazards that beset South America, such as El Nino phenomenon on the coasts of Peru and Chile, the frosts in south-central Brazil, and the droughts of NE Brazil, are not isolated occurrences, but meteorological anomalies whose implications encompass not only the affected areas but also distant environments and economies.Systems analysis is utilized to prove that the oceanic-climatic El Nino phenomenon is genetically linked to global climatic anomalies and that the effects of such anomalies are felt in the ecological balance of the Pacific basin, of Africa, and of S Asia. Among their economic implications are shortages of anomal protein (from fish meal) and crop failures in Africa and the Soviet Union. Political consequences of hazardous conditions are also evident at hand of the 1971–73 climatic oscillations, of which El Nino was a symptom.In order to provide natural hazard research with a coherent theory, the cusp catastrophe theory of Thom and Zeeman is applied to the understanding of the conditions that lead to the onset of an oceanic-climatic El Nino occurrence. It is suggested that — considering that such a situation arises from interdependent ocean-atmosphere feedbacks — only under very special circumstances does this interplay lead to the sudden development of an El Nino condition. Catastrophe theory is not a deterministic theory but it considers the possibility of sudden change of states within a system. 相似文献
17.
Tadeusz Stryjakiewicz 《GeoJournal》1998,44(3):203-213
The geopolitical and socio-economic changes in East-Central Europe that started at the beginning of the 1990s has brought
about a fundamental change in the status of frontier areas in this region. The paper examines the new transborder relationships
as well as the conditions, forms and dynamics of integration processes on the example of Poland. It discusses some stimuli
and barriers to cross-border co-operation, including the creation of new transborder institutional embeddedness (e.g. Euroregions).
On the other hand, the paper stresses the role of the informal economy in the current development of border zones in East-Central
Europe.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
18.
Pablo Pacheco 《Geoforum》2012,43(4):864-874
This paper analyzes frontier expansion in the Brazilian Amazon as a process that depends on multiple exogenous and endogenous factors operating at diverse scales, but whose trajectory depends on the dominant actor type (smallholders or medium- or large-scale landholders) occupying the frontier landscape. Despite the broad growing trend of pasture expansion for adoption of cattle ranching as the main land use associated with frontier expansion, some differences persist across actor types. In relative terms, medium- and large-scale landholders place most of their cleared forestland under pasture, and in absolute terms, largeholders have deforested more than smallholders because they hold larger tracts of land. Recently, however, deforestation activity has been increasing in frontiers occupied by smallholders who tend to convert a greater proportion of the forestland in their landholdings to agricultural land uses than larger-scale landholders, mainly to expand cattle ranching operations. Furthermore, smallholders tend to maintain higher cattle stocking rates than medium- and large-scale landholders, which tend to adopt extensive systems of cattle production. Both economic and human development indices in each frontier type vary according to actor type. While in absolute terms, higher per capita agricultural income levels are found in frontiers where largeholders predominate, the corresponding incomes are higher in smallholder frontiers when prorated by unit of land under crops and pasture. In addition, the Human Development Index is higher in frontiers with greater presence of large-scale landholdings. 相似文献
19.
南美洲铁矿资源丰富、分布广泛、矿床规模大、矿石品位高、类型较齐全。从南美洲大地构造格架分析,分布在克拉通地盾区或其边缘的沉积-变质型铁矿和分布在安第斯海岸造山带的火山成因型铁矿最为重要,沉积-变质型铁矿主要形成于太古宙—元古宙,火山成因型铁矿主要形成于中新生代。综合研究分析,圈出10个铁矿重要成矿区带,主要分布在委内瑞拉的玻利瓦尔州,巴西的阿马帕州、帕拉州、米纳斯吉拉斯州、北里奥格兰德州、巴拉伊巴州、巴伊亚州、南马托格罗索州,玻利维亚的圣克鲁斯州,秘鲁的伊卡—阿雷基帕海岸带和智利的卡拉马—圣地亚哥海岸带等。通过对重要成矿区带内典型矿床的剖析,并采用统计分析方法总结南美洲铁矿成矿时空分布规律,为未来在该区寻找更多的铁矿资源提供参考。 相似文献
20.
本文总结了巴西两个最重要的滑石产地,Parana和Bahia区中滑石矿床的地质特征,并探讨了这些矿床的可能成因。巴西的滑石在世界滑石储量与产量中占有十分重要的地位。巴西Parana和Bahia区的滑石矿主要产于前寒武纪地体中。尽管该区的滑石具有不同的地质产状,与变质火山岩和变质沉积岩共生的滑石最为重要。其他类型的滑石,如与镁铁质-超镁铁质岩共生的、在花岗岩与白云质大理岩接触带的、在花岗岩体中呈包体或顶垂体状的、则相对不重要。在巴西与岩浆活动有关的滑石矿化主要发生在前寒武纪(Bahia区)和白垩纪(Parana区)。滑石的成因模式主要有两类:一为与岩浆热液有关的热液交代成矿模式,另一是起源于盆地热卤水的变质流体交代成矿模式。其中后一种成因模式可用来解释巴西的大多数大型滑石矿床,同时也适用于其他地区,如中国辽宁和乌拉尔南部的滑石成矿。 相似文献