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排序方式: 共有910条查询结果,搜索用时 31 毫秒
101.
THE SIMULATED STORAGE CAPACITY OF FLOOD AND WATERLOGGING IN THE TYPICAL AGRICULTURAL REGION IN JIANGHAN PLAIN 总被引:2,自引:0,他引:2
1INTRODUCTIONJianghanPlainisoneoftheimportantbasesofChina′sagriculturalproductivitylocatedinthemiddleChangjiangRivervalleyofcentralChina.TheJianghanplainapproximately6.6×104km2inareaandover30millioninpopulationistherenowned“countryoffishandrice"in… 相似文献
102.
郭大本 《中国地理科学(英文版)》1991,1(2):141-153
According to practical measurement and related data, the writer discusses the main features of rivers in the Sanjiang Plain and the change of water balance with time and space, and then estimates water resources of five types, namely, runoff, ground water, soil water, and water supplied by three rivers and lakes (or reservoirs).The total volume of the above-mentioned water resources can be up to 31.5 billion m3. But they are rather unevenly distributed and the annual change is considerable, too. Up to now, only 8.3% of water resources have been utilized. According to a programme, 17.5 billion m3 will be utilized in the future in the district. Rationally exploiting water resources in the district should be combined with protection and management, and the sole criterion for judging rationality of utilization is that whether it is beneficial to economic, ecologic and social aspects. 相似文献
103.
蔡述明 《中国地理科学(英文版)》1995,5(3):242-247
THEDEVELOPMENTANDPROTECTIONOFWETLANDSINTHEFOURLAKEAREAOFJIANGHANPLAINCaiShuming(蔡述明)(InstituteofGeodesyandGeophysics,theChine... 相似文献
104.
EFFECTS OF AGRICULTURE RECLAMATION ON THE HYDROLOGIC CHARACTERISTICS IN THE SANJIANG PLAIN, CHINA 总被引:1,自引:1,他引:0
1 THE NATURAL ENVIRONMENTAL CHARACTERISTICS The Sanjiang Plain is located in the northeast of Heilongjiang Province, China. Russia borders this region in the north and east. Its total area is 1.088×107ha. The area of plain occupies 61.21%of the total land area and that of hill and mountain amounts to 38.79%of the total land area. It is not only one of the most important regions with large area of fresh water wetlands and with varieties of rare migratory waterfowls, but a… 相似文献
105.
TheestuarineplainoftheJiulongRiver,whichisthesecondlargestrivernexttotheMinjiangRiverinFujianPrc)vince,intervenesbetweenXi~enandZhangzhoucitiesinthesouthoftheprovince.'I'heplainconsistsofthreeparts:thenorthernplain,thesouthernPlainandZiniIsles.Withsoutllcrn--Subtr<)picoceanicm(>nasexinclimate,itdevelol>saregionalvegetationtypeofeveTgreen13r(Jad--lcav(3dfores[,ofwhicll,however,mosthasbeendestroyedbyhumanbeing.Nowaday-s.shruborgrasslandvegetationcanbeseenonthehillsintheviciTlily'ofthisarea… 相似文献
106.
PALEOSOLSOFSANDYLANDSANDENVIRONMENTALCHANGESINTHEWESTERNPARTOFNORTHEASTPLAINOFCHINAWESTERNDURINGHOLOCENE¥QiuShanwen(裘善文)LiQus... 相似文献
107.
黄淮海平原农区典型村庄用地扩展及其动力机制 总被引:17,自引:1,他引:16
以地处黄淮海平原农区的禹城市伦镇赵庄村为典型案例,利用高分辨率航空遥感数据为基本信息源,结合村庄逐户调查数据,通过土地利用分类与制图,定量研究典型村庄用地格局特征、扩展模式及其动力机制。结果表明:赵庄村土地利用呈"耕地—作业空间—居住空间"的圈层式空间格局。2008年村庄用地规模比1967年增加了1.26倍,主要表现为宅基地的扩展和打谷场用地增长,1985~1990年村庄用地扩展速度最快,村庄用地在空间上向西和向南方向扩展显著。村庄用地扩展主要表现为渐进式蔓延扩展、突变式非地扩展和填充式补充扩展三个阶段。农户居住需求增长与农业生产规模扩大是村庄用地扩展的内生动力,村庄内部条件与外围环境的巨大反差是村庄用地向外扩展的外部环境动力,农户收入增长为村庄用地扩展提供了经济基础,而村庄土地规划缺失与管理缺位使村庄用地扩展失去约束力,这些因素相互作用,共同驱动村庄用地扩展。最后,针对村庄用地扩展存在的问题,提出了促进村庄土地可持续利用的对策建议。 相似文献
108.
109.
TAN Yuanlong QIAO Yansong ZHAO Zhizhong WANG Yan QI Lin FU Jianli LIU Zongxiu YAO Haitao WANG Shubing JIANG Fuchu 《《地质学报》英文版》2013,87(6):1712-1723
In this study Chengdu Red Earth (CRE) from the Chengdu Plain (CP),Sichuan province,was analyzed for its elemental (major and trace elements) and isotopic (Sm-Nd) geochemistry and compared with Pleistocene loess and paleosol samples from the Chinese Loess Plateau (CLP) in Northern China.The geochemical composition of CRE is similar to north China loess,and also resembles the average UCC.This indicates that CRE,as loess deposits in Northern China,was derived from well-mixed sedimentary protoliths that have undergone numerous upper crustal recycling processes.However,obvious differences in the geochemical characteristics of CRE and the north China loess are also revealed in our results.For chemically stable elements,CRE has higher Ti,Zr,Hf and lower ΣREE,Ba contents in comparison with loess samples from the CLP.Further analysis shows that CRE has higher TiO2/Al2O3,SiO2/Al2O3,Ba/Rb and lower Ce/Yb,Eu/Yb,LaN/YbN and ΣLREE/ ΣHREE ratios.In Sm-Nd isotopic geochemistry,Sm and Nd content and the εNd(0) value in CRE are significantly higher than those in north China loess.The higher TiO2 content in CRE coincided with a high background concentration of Ti in the Sichuan Basin and the surrounding regions.The lower ΣREE and higher Sm,Nd,εNd(0) values are related to the wide distribution of basalt in the southwest Sichuan Basin.The elemental and isotopic geochemistry of CRE indicates that eolian materials in the CP predominantly come from the Sichuan Basin and the surrounding regions,which differs from loess deposits in the CLP. 相似文献
110.
东北平原土壤碳库构成具有典型特征:土壤有机碳密度(SOCD)由西部盐碱化、沙化平原向东部低山丘陵增高的趋势,由南向北显示增高趋势,无机碳密度(SICD)具有由西部盐碱化、沙化平原向东部低山丘陵降低的趋势;土壤碳库仍以有机碳为主,不同土壤类型中有机碳密度占总碳密度的56.14%~94.03%,有机碳和无机碳所占比例差别较大;有机碳与总氮呈明显的线性关系,无机碳与CaO呈较强相关性,二者与SiO2均呈较强的负相关性,表明土壤碳库受土壤组成及类型控制最为明显;土壤质地、pH值及其他土壤性质对土壤碳库也具有较大影响,有机碳及无机碳含量与pH值关系的散点图表现为“马鞍型”,但是形状存在微小差别,土壤无机碳含量受碱性条件控制更为明显. 相似文献