我国的土地资源   总被引：4，自引：1，他引：3  

赵其国 《地理学报》1990,45(2):154-162

本文通过与世界土地资源的对比,详细论述了我国土地资源的数量、质量、利用问题及利用途径。随着人口数量的增长,我国土地资源与粮食需求之间的矛盾日益尖锐。目前我国地力减退,土地承载力下降,水土流失,土地沙化,土壤盐碱化及沼泽潜育化,耕地侵占等问题较为严重。为合理开发利用我国的土地资源,本文提出了一些合理化建议,并将全国分成8个土地利用区,进行扼要说明。  相似文献   

BOOK REVIEWS     

《The Professional geographer》1985,37(2):226-262

Book Reviewed in this article: The City in Cultural Context . John Agnew, John Mercer, David Sopher, eds. Soils and Geomorphology Peter W. Birkeland. Urbanization and Settlement Systems, International Perspectives . L. S. Bourne, R. Sinclair, and K. Dziewoński. eds. An Introduction to Urban Historical Geography . Harold Carter. Overshoot, The Ecological Basis of Revolutionary Change . William J. Catton, Jr. Rivers of the World . Eberhard Czaya. Jewish Communities in Frontier Societies: Argentina, Australia and South Africa . Daniel J. Elazar with Peter Medding. Color in Public Spaces: Toward a Communication-Based Theory of the Urban Built Environment. Kenneth E. Foote. Spatial Statistics and Models. Gary L. Gaile and Cort J. Willmott, eds. Mega-Geomorphology. Rita Gardner and Helen Scoging, eds. Technological Change and Regional Development. Gillespie, ed. The Arid Lands: Their Use and Abuse. R. L. Heathcote. The Location of Industry in Britain. A. G. Hoare. Groundwater as a Geomorphic Agent . R. G. LaFleur, ed. Rural Public Services: International Comparisons. Richard E. Lonsdale and Gyorgy Enyedi, eds. Saving Water in a Desert City. William E. Martin, Helen M. Ingram, Nancy K. Laney, and Adrian H. Griffin. Water Resources: Distribution, Use and Management. John R. Mather. Transnationals and the Third World: The Struggle for Culture. Armand Mattelart. South Hadley, MA: USGS Digital Cartographic Data Standards. R. B. McEwen, R. E. Witmer, and B. S. Ramey, eds. The Ecosystem Concept in Anthropology. Emilio F. Moran, ed. Boulder, CO: Women, Men, and the International Division of Labor. June Nash and Maria Patricia Fernandez-Kelly, eds. Nuclear Power: Assessing and Managing Hazardous Technology. Martin J. Pasqualetti and K. David Pijawka, eds. Mary Somerville and the Cultivation of Science 1815-1840. Elizabeth Chalmers Patterson. An Introduction to Coastal Geomorphology. John Pethick. Late Quaternary Environments of the United States , Vol. 1, The Late Pleistocene. Stephen C. Porter, ed. Planning and Ecology. R. D. Roberts and T. M. Roberts, eds. Regionalism and the Pacific Northwest. William G. Robbins, Robert J. Frank, and Richard E. Ross, eds. Environment and Health. Anthony J. Rowland and Paul Cooper. Sunbelt/Snowbelt: Urban Development and Regional Restructuring. Larry Sawers and William K. Tabb, eds. The Bad Earth. Environmental Degradation in China. Vaclav Smil. Armonk, NY: Voyage into Substance: Art, Science, Nature, and the Illustrated Travel Account, 1760–1840. Barbara Maria Stafford. The Institute of British Geographers: The First Fifty Years. Robert W. Steel. Visions of the Past. Christopher Taylor and Richard Muir. Glacial Lake Agassiz. J. T. Teller and Lee Clayton, eds. The Tule Breakers: The Story of the California Dredge. John Thompson and Edward A. Dutra. The Balkan City 1400–1900. Nikolai Todorov. Explanation, Prediction and Planning: the Lowry model. Michael J. Webber. Mercedes Reales: Hispanic Land Grants of the Upper Rio Grande Region. Victor Westphall. The World Atlas of Revolutions. Andrew J. M. Wheatcroft. The West European City, A Social Geography. Paul White. Urban Elites and Mass Transportation. J. Allen Whitt. Princeton, NJ: Urban Life In Contemporary China. Martin King Whyte and William L. Parish. The Demand for Energy in the Soviet Union. David Wilson. London and Canberra: Rethinking Geographical Inquiry. J. David Wood, ed.  相似文献   

Chemical and biological weathering of oil,from the Amoco Cadiz spillage,within the littoral zone     

Ronald M. Atlas  Paul D. Boehm  John A. Calder 《Estuarine, Coastal and Shelf Science》1981,12(5):589-608

  相似文献   

大气退化图像的处理研究   总被引：2，自引：0，他引：2  

周旋  周树道  黄峰  朱福萌 《武汉大学学报(信息科学版)》2005,30(8):720-722

大气退化图像最主要的特征是退化造成的影响和景物与相机的之间的距离相关。针对这种相关性,并结合大气退化图像的特点,提出了一种有效的处理方法,该方法对大气退化图像的处理不需要任何辅助信息。实验表明,该方法具有较好的处理效果。  相似文献   

Decolourisation of textile indigo dye by DC electric current     

M.A. Sanromn  M. Pazos  M.T. Ricart  C. Cameselle 《Engineering Geology》2005,77(3-4):253-261

The electrochemical technology has been employed for the treatment of soils and liquid medium contaminated with aromatic pollutants as indigo textile dye. In liquid medium, 76% of colour removal was obtained in 87 h, and the addition of NaCl (10 g/l) reduced the treatment time up to 45 min. In soils, two alternative methods were developed: a direct electrochemical treatment and the extraction of dye from the soil followed by electrochemical decolourisation of the liquid collected. In the latter process, 50% ethanol in water solution was selected as the best extracting agent. This extracting solution (indigo concentration of 0.5 g/l) was further decolourised electrochemically in the presence of NaCl (10g/l) for 24 h, ending in a colour removal of 70%. Using the direct electrochemical treatment, a regular decolourisation profile along the whole cell was attained. The decolourisation degree was 76% and was reached after 16 days of treatment and an electric power consumption of 61 W·h.  相似文献   

Sediment transport in a highly regulated fluvial system during two consecutive floods (lower Ebro River,NE Iberian Peninsula)     

Damia Vericat  Ramon J. Batalla 《地球表面变化过程与地形》2005,30(4):385-402

The transfer of sediment through a highly regulated large fluvial system (lower Ebro River) was analysed during two consecutive floods by means of sediment sampling. Suspended sediment and bedload transport were measured upstream and downstream of large reservoirs. The dams substantially altered flood timing, particularly the peaks, which were advanced downstream from the dams for flood control purposes. The suspended sediment yield upstream from the dams was 1 700 000 tonnes, which represented nearly 99 per cent of the total solid yield. The mean concentrations were close to 0·5 g l^?1. The sediment yield downstream from the dams was an order of magnitude lower (173 000 tonnes), showing a mean concentration of 0·05 g l^?1. The dams captured up to 95 per cent of the fine sediment carried in suspension in the river channel, preventing it from reaching the lowermost reaches of the river and the delta plain. Total bedload transport upstream from the dams was estimated to be about 25 000 tonnes, only 1·5 per cent of the total load. The median bedload rate was 100 gms^?1. Below the dams, the river carried 178 000 tonnes, around 51 per cent of the total load, at a mean rate of 250 g ms^?1. The results of sediment transport upstream and downstream from the large dams illustrate the magnitude of the sediment deficit in the lower Ebro River. The river mobilized a total of 350 000 tonnes in the downstream reaches, which were not replaced by sediment from upstream. Therefore, sediment was necessarily entrained from the riverbed and channel banks, causing a mean incision of 33 mm over the 27 km long study reach, altogether a significant step towards the long‐term degradation of the lower Ebro River. Copyright © 2005 John Wiley & Sons, Ltd.  相似文献   

The impact of land degradation on landscape in Northern Greece     

B. Anthopoulou  A. Panagopoulos  Th. Karyotis 《Landslides》2006,3(4):289-294

Large areas of Greece are seriously degraded and landscape deterioration is mainly influenced by climatic factors, geological factors, overgrazing, forest fires and urbanisation. The examined area of Saint Panteleimon is located in northern Greece on the foot-slope of Mt. Olympus and exhibits aesthetic beauty of significant value owed to specific ecological, historical and cultural conditions. Due to intensive erosion and other geological factors, the old village, which is characterised by unique architecture, was abandoned. In the study area is located the castle of Platamon, which is dated to 1222 a.d. Overgrazing, which was very common a few decades ago, has enhanced erosion and affected the surrounding landscape. Another case of degradation concerns forestland, where erosion and landslides have influenced the loss of surface soil layers resulting in vegetation decline. The erosion impact increased due to urbanisation and recreational activities. Management of degradation at a local scale is very complex and requires a multidisciplinary approach. Recent works for soil stabilisation in conjunction with efforts for maintaining and recovering the protective vegetation have increased the degree of protection. Priorities for environmental protection in the study area are proposed to focus on reforestation, rational management of rangeland and restoration of hydrologic conditions of the watersheds.  相似文献   

Analysis of soil biogeochemical characteristics in the process of karst rocky desertification     

Hongmei LU Shijie LU Yuanhua PENG 《中国地球化学学报》2006,25(B08):175-176

The sampling method of karst soil is always the one used for non-karst area. However, if the samples can represent the plot, it still needs further investigation due to high degree of spatial variability of karst soil. The study results of soil from the Maolan karst virgin forest in Guizhou Province elucidated that only the surface area-weighted samples could represent plot soils in the karst ecosystem. The remediation of karst rocky desertification has currently become a national issue, but soil degradation research on rocky desertification genesis types and processes is still insufficient. Soil physical, chemical, biological characteristics and enzymes activities from plots of different rocky desertification genesis types and grades in the Cha＇eryan catchment in the Huajiang Gorge area, Guizhou, were studied. The results showed that woodcutting and land reclamation influenced soil biogeochemical characteristics, and the influence of different disturbing ways was huge. The author suggested a soil degradation index system which could illustrate the rocky desertification genesis type and extent. The degraded modes of woodcutting and reclamation sequence were different, both had no synchronism with rocky desertification grades divided by current landscape index. Only soil of serious grade degraded evidently in wood cutting sequence. On the contrary, soils of slight, medium and serious grades degraded evidently in the reclamation sequence.  相似文献   

大小兴安岭多年冻土退化及其趋势初步评估   总被引：18，自引：19，他引：18  

金会军  于少鹏  吕兰芝  郭东信  李英武 《冰川冻土》2006,28(4):467-476

大小兴安岭多年冻土处于欧亚大陆多年冻土带南缘,地温高、厚度小、热稳定性差、对气候变暖的敏感性强.过去40 a来该区多年冻土退化主要表现为最大季节融化深度增大,厚度减薄,地温升高,融区扩大,多年冻土岛消失等.气候变暖及该区森林植被的锐减是导致多年冻土退化的普遍性和基础性因素,而多种人为活动影响起了加速促进作用.依据多年冻土南界与多年平均气温的密切相关关系,据1991—2000年平均气温-1.0~1.0℃等值线给出了现今多年冻土南界位置,并探讨了未来40~50 a后气温升高1.0~1.5℃情况下多年冻土南界的可能北移情况.  相似文献   

Aqueous reactivity of phytoliths and plant litter: Physico-chemical constraints on terrestrial biogeochemical cycle of silicon   总被引：1，自引：0，他引：1  

F. Fraysse  F. Cantais  O.S. Pokrovsky  J. Schott  J.D. Meunier 《Journal of Geochemical Exploration》2006,88(1-3):202

Quantification of silicon recycling by plants is hampered by the lack of physico-chemical data on reactivity of natural phytoliths and plant litter. In this study, we used an experimental approach for determining the silica release rates of phytoliths from tropical and temperate plants (bamboos, horsetails). Results are compared with litter degradation of horsetails and pine needles. Silica release rates suggest that the reactivity of phytolith surface does not depend on topology and geometry of local structures, and does not support the existence of preferential dissolution sites on surface. Litter degradation results suggest that the silica release rate is independent of cellulose hydrolysis that implies the presence of phytoliths in an “inorganic” pool not complexed with organic matter.  相似文献