首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 31 毫秒
1.
M. Y. Une 《GeoJournal》1982,6(2):129-140
Frost damage on coffee plantations in south-central Brazil is not a frequent occurrence. However, when this area is affected by a severe frost — as happened in August of 1975 — the consequences for the agricultural economy of south-central Brazil and the socio-economic condition of the rural labourers are serious.In this paper the meteorological characteristics of a frost condition are outlined and their physiological effects upon coffee bushes are stated. A differentiation is made as to the timely occurrence of frosts and their effects on crops. If the frost hits during harvest time (April through June) the beans may be burned and a qualitative loss may ensure. If the frost occurs after the harvest, only the coffee bushes are affected and they may have recovered by the following agricultural year. The most devastating frosts are those that occur late in winter (August-September) because they kill the buds and the flowers so that next year's harvest will be lost.Coffee in south-central Brazil is usually grown on plantations of 10 to 100 ha, and 100 to 1000 ha. There has been a trend to expand the coffee growing area into Mato Grosso-Rondonia, while in the state of Parana, where frosts are more severe but the soils are better, coffee growing in large estates has intensified. Moreover, the introduction of new methods of planting and mechanization of the agricultural work have brought about an intensification of coffee production. Analysis of the improvements in cultivating pratices and of agricultural mechanization that these two processes have caused a drastic reduction in the demand for agricultural labourers. Added to this, the possibilities of rural employment have also been adversely affected by the trend among many coffee growers to introduce other crops into their estates in order to minimize their losses due to frost.  相似文献   

2.
Mira Ovuka 《GeoJournal》2000,51(3):203-209
Land use changes in Kenya's central Highlands were examined with the purpose of comparing findings from Murang'a District with a new study carried out in a similar environment, Nyeri District. In addition, a generalisation of the findings was examined and methods were analysed to investigate its use in other areas. Aerial photographs were used to analyse land use and soil and water conservation in form of terraces. Furthermore, farmers were interviewed in order to obtain information about how they perceive environmental changes and how these changes have affected their livelihoods. Interpretation of aerial photographs together with field verification and interviews give information about environmental changes and their effects. Population censuses were investigated and findings were compared. Results from this study show that the two study areas have similar physical conditions with decreasing soil fertility. The main difference is the cultivated cash crops, tea and coffee in Nyeri, but only coffee in Murang'a. Also, more land is terraced in Nyeri than in Murang'a. The reason why there are adequate terraces in Nyeri is because of the multitude of cash crops that require terraces for their establishment. Compared with Murang'a, farmers in Nyeri are more satisfied with their situation, mainly due to regular payment from tea and a lower population pressure. This study shows that generalisation of the findings can be made but in order to extrapolate it further to the whole central Highlands more studies and knowledge about the whole area are required. The study also shows that methods used to examine environmental changes can be used elsewhere. Although the recommendations are to generalise with caution so that the final results are reliable and true.  相似文献   

3.
Commercial hydrocarbon production had evaded Australia for a long time. Despite a number of encouraging discoveries during the first half of the century, commercial exploitation was not achieved until 1961, when the Moonie oil field was discovered in eastern Queensland and natural gas delivered for electricity generation to the town of Roma. Additional discoveries followed in quick succession. At the beginning of the 1970ies the basic pattern of oil and gas production had been established but both, adverse political influences and sociological issues severely curtailed exploration and delayed the development of some of the fields by almost 20 years. Discovery rate was reduced but new fields have been found in the Timor Sea, both off- and onshore West Australia, in South Australia and in Queensland.Indigenous oil production amounst to about 80% of domestic requirements. Production potential of natural gas far exceeds domestic consumption. Preparations for export of LNG are well advanced. Indigenous oil production is expected to decline within the next years unless new resources are discovered. More than 50% of the Australian continent is covered by sedimentary basins and the area of offshore basins is equally vast. Potentially petroliferous strata contained within them range from the late Precambrian to the Neogene. Drilling density in these basins is generally low and their potential has barely been assessed. Assuming a favourable exploration climate these basins have sufficient potential to ensure a high level of self sufficiency for the future.  相似文献   

4.

The study analyzed the food security and dietary diversity of tea workers in Lakkatura Tea Garden and Ootterbhag Tea garden in greater Sylhet district of Bangladesh. A total of 200 respondents (100 from each tea estate) were interviewed to evaluate the food security and dietary diversity. The study found that average daily per capita calorie intake by tea workers was 2095.96 kcal. In addition, around 85.30% of the total calorie intake was received from the rice consumption. Average per capita daily intake of rice was estimated at 538.51 gm which is higher than the national average. It was also observed that 71.7 and 65.0% households were food secure in Lakkatura and Ootterbhag Tea garden, respectively. In Lakkatura Tea Garden, 61.67% tea workers have medium dietary diversity and in Ootterbhag Tea Estate 49.47% tea workers have low dietary diversity. Using the logit model analysis, this study provides food consumption patterns of tea workers and determine the factors responsible for food security. Household size, farm income and daily calorie intake were found having significant influence on households’ food security. For improving socioeconomic conditions of tea workers, educational institution should be set up to improve their educational status and government should give loans for them at a low interest rate and create alternative job opportunity in off season.

  相似文献   

5.
This paper explores the following general question: Why are Fair Trade coffee farmers in Nicaragua burdened by debt? Nearly five years from “the end” of the coffee crisis, peasant farming households committed to Fair Trade standards continue to struggle with a legacy of indebtedness caused by years of low farm-gate prices and declining productivity between 2000 and 2004. Through ethnographic observation and interviews with peasant farmers in Nicaragua, I explore how farmers experience a simple reproduction squeeze that hinders them from “bootstrapping” their own economic development. I argue that the effort to raise the Fair Trade minimum price and premium for coffee through Fair Trade Labelling Organizations International (FLO) in 2008 demonstrated a good first step toward improving farm-gate prices, however, these gains must be understood in the context of long-term indebtedness as well as rising production costs and household consumption costs.  相似文献   

6.
浙江“安吉白茶”产地地质地球化学特征   总被引:2,自引:0,他引:2  
通过对安吉白茶产地地质、地球化学特征的系统研究,认为成土母岩、土壤元素组合等对茶叶的品质均具有深刻的影响。母岩(母质)类型不同,土壤类型、质地、pH值,尤其是土壤地球化学成分就会具有很大的差异,钾、硅、铝和酸性土壤有利于茶叶生长发育,钙、镁、钠和碱性土壤不利于茶叶品质的提高。茶叶硒、锌含量高,其生化成分与土壤中钾、钼、锰、硫、磷的有效态呈显著正相关。因此,建议发展白茶基地应在安吉中部、东部低山丘陵区,选择以石英砂岩、岩屑砂岩风化残坡积物为母质的土壤。  相似文献   

7.
中国与美国同为世界煤炭生产、消费大国。作为发达国家,美国煤炭生产、消费等许多方面都有值得中国借鉴之处。本文从美国近几年煤炭生产、消费等方面的发展状况,结合中国煤炭生产、消费等形势,提出使中国煤炭持续发展所值得思考的问题。   相似文献   

8.
茶园土壤不同形态镍的含量及其影响因素   总被引:3,自引:2,他引:1  
通过自然茶园土壤采样和室内实验分析,探讨浙江、江苏和安徽13个茶园土壤镍的污染状况、形态分布规律以及不同形态镍的含量与土壤镍总量和土壤理化性质的关系。结果表明:部分茶园土壤受到不同程度的镍污染;茶园土壤镍的形态分布有一定差异,按镍的含量多少排序,一般为残渣态>交换态>铁锰氧化物结合态>有机结合态>碳酸盐结合态;除了交换态以外的所有其他形态的镍含量均随土壤镍含量的增加而显著增加;碳酸盐结合态、铁锰氧化物结合态和残渣态镍含量随土壤pH的升高呈显著增加趋势,而交换态镍则呈减少趋势,但不显著;随土壤有机质含量的增加,铁锰氧化物结合态镍显著减少,而其他形态增加或减少的趋势均不显著;碳酸盐结合态、有机结合态和残渣态的镍含量均随阳离子交换量的增加显著增加;随粘粒含量的增加所有形态中的镍呈增加趋势,但除了残渣态外增加趋势均不显著。  相似文献   

9.
稀土元素在永磁材料等新材料领域有着广泛的应用,被世界各主要国家列为战略资源.从资源、生产格局上看,近年来随着世界范围内稀土探矿热潮的出现以及中国稀土资源的大量开发,中国稀土资源优势地位正逐渐降低;美国等西方国家大力推动中国之外稀土矿山和冶炼分离项目的建设,全球稀土生产格局或将发生变化.从消费方面看,稀土消费可被归为永磁...  相似文献   

10.
The importance of obsidian from the northern Patagonian source at Las Cargas is reflected in its early use (∼8000 years B.P.) and extensive geographic diffusion but is nonetheless surprising in light of the source's high altitude (located in the Andes Cordillera), which makes it both difficult to access under ideal conditions and inaccessible for much of the year. Prehistoric use of the Las Cargas source can inform us about mobility, subsistence choices, economics of stone consumption, trade, and territoriality. Here we present the results of various lines of evidence (surface survey, X‐ray fluorescence and instrumental neutron activation analyses, artifact morphometry, and obsidian hydration dating) used to characterize obsidian from Las Cargas and its prehistoric use during the Holocene. Results indicate that Las Cargas obsidian occurs at the source as blocks and nodules, which are chemically homogeneous and of variable quality. Use of the source was nearly continuous through time, and the primary knapping activities performed there were the production of blanks and preparation of cores.  相似文献   

11.
Nagel  Anne-Hilde 《GeoJournal》1994,32(2):137-149
The growth of Norwegian mining industry was part of the modernization process that constituted the early modern period in European history. Mining introduced industrial capitalism in Norway, with machines, division of labour, wage-earning and production for profit, social classes of proletarians and capitalists. For Norway then, mining played an important part in the mercantilist economic policy of the early modern period, where growth of industry was an aim, and where statebuilding was looked upon as a mean, but also as a wanted result. Thus for Norway, the statebuilding process started before independence as a souvereign state was gained in 1814. In both these aspects, as an early industry and as an object of politics, institutions and bureaucracy, mining in Norway was heavily influenced by the Saxonian tradition.  相似文献   

12.
The Quaternary period in the Pamir and Tien-Shan is marked by a sharp increase in the intensity of uplift which followed a short tectonically calm period in the late Pliocene and the early Pleistocene. Rates of the upward movement increased from the early Pleistocene to Holocene. The structural pattern of the region was formed throughout the whole neotectonic stage but the present shape is mainly the result of the Quaternary movements. A number of large uplifts and relative depressions can be identified in the Tien-Shan and Pamir. Only some of the greatest depressions were subject to absolute downwarping in their central parts during the Quaternary time. Numerous new data on the thickness of the earth's crust of Central Asia obtained in the past few years have allowed construction of a new relief map of the Mohorovičić discontinuity in the Tien-Shan and Pamir and of the discontinuity in relationship to the character of the Quaternary tectonic movements. As a result, correspondences relating to the development of the earth's crust were established and a suggestion was made as to the current rejuvenation of the structural pattern, with both an anti-Tien-Shan and a meridional direction dominating in the Pamir. The comparison of the development of the earth's crust as a whole with the lateral heterogeneities of the upper mantle confirmed the assumption about the current rejuvenation. At the same time it made evident once again that there are significant differences in the deep processes taking place in the Pamir and Tien-Shan. Combining analyses of both the subsurface and the surface development in this part of Asia provided a better view of the characteristics of the deep fault zones. This has allowed the authors to outline the latent ruptures and establish individual blocks of the earth's crust that show different structure and development.  相似文献   

13.
D. Dragovich 《Geoforum》1980,11(2):147-156
An important proportion of Australian dairy production has been destined for export markets, where prices are below those received on the home market. This degree of dependence on international prices has adversely affected dairy farm incomes and thereby influenced both Government responses to the industry's problems and dairymen's decisions about levels of production and farm viability. Examination of the spatial impact on the now declining Australian dairy industry of Government-funded subsidies and of schemes for reconstruction of non-viable dairy farms, has indicated that withdrawal of farmers from the industry has not been areally uniform at the national level; but study of a major dairying region whose industry has undergone substantial decline suggests that this uneven pattern reflects industry and regional characteristics more than the deliberate or inadvertent results of Government intervention. Although Government policy has been broadly directed towards reducing the numbers of dairymen, and hence dependence on overseas prices for production surpluses, industry change has been greatest in regions where viable economic alternatives have been available for low-income dairymen.  相似文献   

14.
福建铁观音茶园生态地球化学特征   总被引:4,自引:2,他引:2       下载免费PDF全文
东南沿海是铅等重金属的地球化学高背景区。该地区广泛分布酸性红壤,酸雨沉降、不适当施肥导致土壤酸化以及由此引发土壤重金属生态风险令人关注。以福建省铁观音主产区为研究区,采集了79个茶园的表层和亚表层土壤样、茶叶样品,测定了重金属元素以及土壤常量元素和理化指标。研究表明,福建铁观音茶园土壤中Hg、Pb、Se、Zn高含量主要由地质背景所引起,土壤常量组分、有机质、酸碱度等理化条件对土壤元素含量有一定的影响;铁观音茶树老叶中As、Cd、Cr、Hg、Se、Pb、F等非植物营养元素含量明显高于嫩叶,显示这些元素随植物生长逐渐累积的特征,而嫩叶中植物生长必需的营养元素Cu、(Ni)、Zn则高于老叶,反映出微量营养元素在茶叶生长部位相对富集的特征;多数情况下土壤与茶叶间元素含量相关性差,说明茶树对土壤元素的吸收累积受到多种复杂因素的影响。研究表明茶叶与土壤Pb、Cr具有显著正相关性,为建立铅污染土壤生态效应预测评价模型提供了基础依据。  相似文献   

15.
We examined the effects of dredged material disposal on benthic macroinvertebrates in Galveston Bay, Texas, USA, while investigating the utility of estimating secondary production with estimation methods that have less rigorous data requirements than most classical techniques. Production estimates were compared to estimates of benthic consumption by blue crabs, shrimp, and epibenthic fish. There was no evidence that dredged material disposal had a detrimental impact on benthic production; however, production was low throughout the entire bay the year following dredged material disposal, which may have obscured an assessment of the impact of disposal. In fact, disposal sites yielded both the highest production estimates and species richness in both the upper and lower bay areas 2 yr after disposal. Of the five estimation methods used, two that incorporated environmental parameters (temperature and depth) yielded similar and moderate results, ranging from 1.1 g ash-free dry weight m2 yr1 to 26.9 g ash-free dry weight (AFDW) m?2 yr?1 over the 4 yr studied. Daily food ration estimates applied to fishery-independent trawl-survey data yielded overall benthic consumption estimates ranging from 1.1 g AFDW m?2 to 1.7 g AFDW m?2. A second method of estimating consumption, which used transfer efficiency estimates and annual fisheries statistics produced slightly lower benthic consumption estimates (0.72–1.13 g AFDW m?2). The average consumption estimate exceeded benthic production in the upper bay in one of the 4 yr for which benthic production was estimated. In years with high benthic production, the estimated benthic food requirement of epibenthic predators was roughly 10–15% of benthic production. Variation in annual benthic production estimates was two to three times greater than the variation in consumption estimates.  相似文献   

16.
天然气因其丰富的储量和清洁低碳的属性受到世界各国普遍重视。在未来30~50年内,天然气的消费量和比重还会继续上升,预计在2040年前后将成为第一大能源。科学分析天然气全球供需格局和研判其未来变化,是科学制定中国天然气发展战略的前提和基础。全球天然气的生产和消费严重分离,形成了基本的天然气供需格局。但新世纪以来,天然气领域全球出现了许多重大而影响深远的变化,美国页岩气革命改变了天然气的供应格局,2013年的俄乌争端将改变了天然气的贸易格局,固有的市场体系必不可免地随之改变。中国天然气需求的增速将大大高于产量的增速,天然气供需缺口将不断扩大。本文提出了我国天然气发展的战略思路,对我国天然气需求的供应保障和产业的可持续发展具有重要的理论和实践意义。  相似文献   

17.
塔河油田奥陶系碳酸盐岩缝洞型油藏的储层非均质性强,油水分布状况复杂。弄清其在区域尺度上(10 km×10 km)的宏观油水分布规律,对于缝洞型油藏开发过程中的控水稳油意义重大。本文以塔河油田十区西为研究区,在全方位高精度三维地震数据处理、解释和反演的基础上,对岩溶古构造和开发过程中的油水动态进行综合分析,探讨研究区碳酸盐岩缝洞型油藏的油水宏观平面分布格局的控制因素。结果表明:研究区在加里东中期第I幕岩溶发生期形成了相对均匀的古岩溶含水层,在海西早期油气充注进古岩溶含水介质以后,海西晚期发生的深部热液活动对缝洞体进行了封闭定容,造成缝洞分隔,并且奠定了目前油水在平面上的宏观分布格局。  相似文献   

18.
Lu Wang  Lucia Lo 《GeoJournal》2007,68(2-3):183-194
Acquiring consumer goods and services in the destination country signifies a different type of immigrant experience. This is especially pertinent in world cities where there is a strong presence of ethnic economies and where co-ethnic businesses and mainstream businesses compete against each other. The consumption pattern of immigrants is influenced not only by their pre-migration shopping habits, but also their post-migration transnational behaviour. In this paper, we focus on the consumption experience of Chinese immigrants in Toronto, which hosts one of the largest Chinese ethnic economies outside Asia. Based on a random survey and two focus group discussions, we explore how Chinese immigrants choose between ethnic Chinese and mainstream supermarkets, electronic stores and travel agencies. In theory, Chinese and non-Chinese stores providing similar goods and services are substitutes. The study however reveals intriguing results. Chinese and mainstream travel agencies are substitutes but Chinese and mainstream supermarkets and electronic stores are complements. Such differences reflect the importance of ethnicity and culture in immigrants’ consumption behaviour. The paper provides new evidence on immigrant integration in the domain of consumption and contributes a consumer perspective to the literature on ethnic economy and transnationalism.  相似文献   

19.
http://www.sciencedirect.com/science/article/pii/S1674987111000405   总被引:1,自引:0,他引:1  
This study has focused on the processes of soil degradation and chemical element concentration in tea-growing regions of Rwanda, Africa. Soil degradation accelerated by erosion is caused not only by topography but also by human activities. This soil degradation involves both the physical loss and reduction in the amount of topsoil associated with nutrient decline. Soil samples were collected from eleven tropical zones in Rwanda and from variable depth within each collecting site. Of these, Samples from three locations in each zone were analyzed in the laboratory, with the result that the pH of all soil samples is shown to be less than 5 (pH < 5) with a general average of 4.4. The elements such as iron (Fe), copper (Cu), manganese (Mn), and zinc (Zn) are present in high concentration levels. In contrast calcium (Ca) and sodium (Na) are present at low-level concentrations and carbon (C) was found in minimal concentrations. In addition, elements derived from fertilizers, such as nitrogen (N), phosphorous (P), and potassium (K) which is also from minerals such as feldspar, are also present in low-level concentrations. The results indicate that the soil in certain Rwandan tea plantations is acidic and that this level of pH may help explain, in addition to natural factors, the deficiency of some elements such as Ca, Mg, P and N. The use of chemical fertilizers, land use system and the location of fields relative to household plots are also considered to help explain why tea plantation soils are typically degraded.  相似文献   

20.
通过野外采样和室内测定,以日照茶树种植区3个典型茶园为研究对象,每个茶园分别取鸠坑、黄山群体、福鼎大白各3个品种。最终取得9种茶样生长地的土样,研究分析土样的pH。有机质,全N,P,K,有效N,P,K等指标的土壤养分含量状况,并以此为评价指标,运用模糊综合评判法,对3个茶园的土壤肥力质量进行了综合评价。结果表明,茶园肥力综合水平为北垛春〉碧波山庄〉北叶青i茶园土壤总体上,pH值较适中,有机质含量很缺乏,全N含量偏低,全P含量中等,全K含量较高,有效N含量很缺乏,有效P含量非常丰富,有效K含量中等,并据此提出了关于该地区3个典型茶园今后合理施肥的一些建议。  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号