安徽省江淮丘陵地区干旱问题的探讨

一、前言 安徽省江淮地区耕地率较高,全区总面积有65,000平方公里,耕地面积占有3,035万亩。区内主要的地貌类型为丘陵,丘陵地区的耕地面积可占全区总耕地面积的四分之三以上,为安徽重要的农业基地之一。     

安徽省江淮丘陵地区干旱问题的探讨

一、前言 安徽省江淮地区耕地率较高,全区总面积有65,000平方公里,耕地面积占有3,035万亩。区内主要的地貌类型为丘陵,丘陵地区的耕地面积可占全区总耕地面积的四分之三以上,为安徽重要的农业基地之一。     

阿克苏地区农业生产合理布局问题初步讨论

阿克苏地区位于天山南坡和塔克拉玛干沙漠之间,包括库车、新和、沙雅、拜城、乌什、温宿、阿克苏、阿瓦提、柯坪九县,共17个农垦团场,64人民公社,43个地方国营农、林、牧、渔场。土地总面积13.6万平方公里,占自治区土地面积的8.3％。新老绿洲面积8198.4平方公里,人口142万人,其中农业人口115万,占总人口的81％,平均人口密度每平方公里9.5人,但绿洲人口密度173人。1976年全区耕地面积637.7万亩,垦殖率仅3.1％。     

论豫西黄土丘陵区的综合治理与开发

豫西黄土丘陵台地位于河南省西部,西邻陕西,北濒黄河,南与伏牛山区交错,东同黄淮平原接壤。包括三门峡、洛阳、郑州三市的大部和平顶山、许昌两市的部分地区,共计21个县、市。总土地面积约24733平方公里,总人口1128万人,分别占全省土地面积和总人口的14.8％和12.3％。区内耕地面积1392万亩,占全区土地总面积的40％,人均耕地1.23亩,同全省人均耕地数量相当。由于本区地处西部黄土高原与东部黄、淮、海平原的交接和过渡地带,在特定的环境条件下,当前已经成为河南     

内蒙古自治区土地资源可持续利用分析

<正>1内蒙古土地资源利用现状根据内蒙古自治区2008年土地详查变更数据统计,全区土地总面积为11550.92万hm2。其中农用地9541.45万hm2,建设用地149.24万hm2,未利用地1860.23     

改善生态环境 提高抗灾能力

<正> 浙江省建德市是一个“九山半水半分田”的山区市,土地总面积2327万平方公里,其中耕地面积2.42万公顷,林业用地18.49万公顷,农业人口40.80万人,农村人均耕地0.06公顷,人均宜林地0.45公顷。 建国以来,我市在国家各级林业主管部门的领导与支持下,大力发展林业事业,改善生态环境,取得了长足发展,特别是改革开放二十年来,我市两个文明程度有了翻天覆地的变化,已成为杭州一黄山黄金旅游线上的     

三明市山区的开发利用

三明市位于福建省西北部,全市辖12个县(市、区),人口221万人,其中农业人口174万人。境内的土地总面积3452万亩(2.3万平方公里),其中耕地面积256万亩,占7.4％,人均1.47亩;林地面积2716万亩,占78.7％,人均15.61亩;水域面积75万亩,占2.2％,素有“八山半水一分田半分道路和乡村”之称。全市地处武夷山与戴云山间,东部为戴云山的西坡地带,多低山,相对高度200米左右;西部为武夷山的东坡地带,地势较开阔,多低丘,相对高度100—150米,泰宁白石顶海拔最高为1858米,东     

依靠科技进步 绿化千里太行

<正> 林州市地处河南省最北部,是晋、冀、豫三省交汇接壤的中心,全市总面积20.46万公顷,耕地面积仅为5.3万公顷,林业用地面积达3.2万公顷,属典型的干旱石质山区,是我省太行山区林业用地面积最大,造林条件最为艰巨的县(市)之一。截至1997年底,全市已完成荒山绿化面积9.6万公顷,实现了     

依靠科技兴林 建设绿海甜园

<正> 北京市大兴县属平原县,地处首都南郊、永定河左岸,距京城20公里。全县辖27个镇乡,总人口54万。总土地面积10万公顷,耕地面积6万公顷,沙化土壤占全县总面积的70％以上。改革开放以来,全县经济发展迅速,1995年,全县工农业总产值达46.5亿元,财政收入2.13亿元,人均存款5597元。     

浅谈河北山区土地资源的开发利用

河北山区跨省境53个县(市),土地面积94553Km~2,占全省土地总面积的50.4％;耕地面积151.3万公顷,占全省耕地面积的22.6％;农业人口1200多万人,约占全省农业人口的1/4;山区的木材、粮食、油料、干鲜果以及蚕桑、药材等,都占全省较大比重。开发利用好山区土地资源,对发展山区经济,改善生态环境及增强农业发展后劲等有深刻影响。 一、河北山区土地资源形成的自然环境特征 (一)地质条件复杂,地貌类型多样:河北山地基本上由燕山和太行山两大山脉组成。全境构造复杂,岩性多样。山体主要由花岗岩、片麻岩、石英岩及石灰岩等组成。海拔多在2000m以下,中、高山占山区总面积的46％,相对高度多在500—800m,坡度20—40°;低山丘陵占36％,低山浑圆,河谷宽阔,丘陵区黄土普遍分布,切割     

Reconstructing the development of the geosystems of the Primorsky Range during the latter half of the Holocene

We examine the sequence of changes in the structure of the geosystems of the Primorsky Range (Baikal region) for the last 6000 years, based on a continuous recording of fluctuations of the vegetation reconstructed from spore-pollen complexes of a high peat bog. We determined the chronological timeframe of paleogeographical events. The study showed that there occurred a radical structure transformation of the geosystems in the mid-late Holocene, along with a recurrence of similar landscape transformations caused by the instability of natural conditions.     

On the origin of the seismic anisotropy of the lithosphere

Summary. It is known that flow in the mantle can produce preferred orientation in olivine crystals with seismic anisotropy as a consequence. Flow in the subcrustal lithosphere is unlikely because of the high viscosity. Lenses of high temperature and low-viscosity ( anomalous mantle ) are located under the crust in many tectonically active regions, and viscous flow can easily arise in such material resulting in seismic anisotropy. After cooling, such anomalous mantle acquires high viscosity and becomes incorporated into the lithospheric layer preserving the anisotropy produced by the flows which existed previously. The interaction of the stresses with cracks in the upper crust can be one of the causes of anisotropy in this layer.     

对沙漠化农田能转化效率及潜力的分析

我国北方东起黑龙江省嫩江地区, 吉林白城地区及辽宁西部, 包括内蒙兴安盟东南、哲里木、昭乌达、锡林郭勒、乌兰察布、伊克昭等盟的大部地区, 直至河北坝上、陕西榆林北部约26.7万平方公里的幅员范围内, 由于自然条件的特殊性(地表组成物质质地松散、沙粒成分比重很大及气候干旱、多大风, 且年内季风与周期性干旱相吻合), 加上人类不合理开发活动的影响, 成为我国目前沙漠化发展最活跃的地区, 其沙漠化土地近16.5万平方公里, 占全区总面积的61.5%。该地区有较长的经济开发史, 农、牧业相互影响, 交错分布的情况, 在历史上业已形成。据粗略统计, 该区范围内, 有旱作耕地近5, 000万亩, 多以传统的粗放的撂荒种植制进行经营, 长年遭受不同程度的风沙危害, 属于生产水平较为低下的农田类型。这些农田急待整治, 以便提高生产力。由于本区年均降水量在350-450毫米之间, 客观上具有发展旱作农业的可能性。如能合理经营、科学利用其自然资源, 将可能发展成为农、牧业结合的发达地区。从而对我国北方地区农业发展起促进作用。为了深化对沙漠化农田的认识, 揭示其生态失调的实质, 本文将就生态系统观点对其进行分析以寻求有效的整治沙漠化农田的途径。     

Direct determination of the characteristics of the currents responsible for the geomagnetic anomaly of the Rhinegraben

Summary. Previous geomagnetic measurements in the Rhinegraben have led us to assume that the responsible currents have the properties of direct currents and that they all flow in the sediments filling the graben. In order to verify these conclusions, we have performed measurements in a mine at a depth of 650 m. By comparing the field simultaneously recorded at the surface, in the mine and at the reference station, it is possible to deduce that the anomalous currents have the above mentioned properties.     

城市化的开发区模式研究

我国许多城市通过开发区建设,在短时间内完成了产业和人口的集聚,实现了城市地域空间和人口规模的跳跃性增长和产业结构的转型。由于在这种城市空间增长过程中,开发区建设起了决定作用,因此,这种以开发区带动整个地区城市化的方式可称为"开发区模式"。开发区驱动城市化的机制表现在开发区自身区域的城市化和开发区带动周围农村地区城市化两个层面,并具有快速跳跃性、外驱性和不稳定性、人为性、经济增长模式的单一性和基础设施建设的高标准性等特征。针对开发区建设中出现的问题,提出了促进其健康发展的建议。     

Chemical composition of waters and the phytoplankton of the lakes within the delta of the Selenga river

Field observations showed that the characteristics of chemical composition of waters and the development of plankton algae in the lakes within the delta of the Selenga river are determined by their flowage. The most open Lake Nekipelovskoe communicates with the Selenga outlets throughout a year, and Lake Zavernyaikha only at the period of an open channel. Lake Semenovskoe and Lake Khlystov Zaton are located in the islands and are isolated from the outlets. According to composition of main ions, the lakes under investigation refer to the hydrocarbonate class, the calcium group. The sum of ions in the water of Lake Nekipelovskoe approaches the one in the Selenga (86?221 mg/dm³), and the highest sums of ions were recorded in the wintertime in the lakes isolated from the outlets (446?743 mg/dm³). The lakes of the delta are characterized by a high trophicity. The maximum concentrations of total phosphorus in Lake Nekipelovskoe and Lake Zavernyaikha were 68 and 122 μg mg/dm³, and in Lake Semenovskoe and Lake Khlystov Zaton ?0.8 and ?0.63 μg mg/dm³, respectively. The most intense development of algae is observed in Lake Zavernyaikha, which is due to the high population of Baikal endemics. Lake Zavernyaikha showed a close negative correlation between the concentration of NO ₃ ^? , mineral phosphorus and phytoplankton biomass; the correlation coefficient was ?0.8 and ?0.63, respectively. The lakes exhibited increased contents readily hydrolysable organic matter, and a decrease in dissolved oxygen concentration in winter; hydrogen sulfide was repeatedly recorded in Lake Khlystov Zaton. The water quality in the lakes during the springtime varies from “quite clean” to “weakly polluted”; at low-water periods, especially in winters, it can drop to the category of “exceedingly dirty”. The water quality of the Selenga can be influenced by the lakes during spring floods when material accumulated during the wintertime is transported to the river outlets and further to Lake Baikal.     

Transformation of the vegetation cover in the zone of air emissions from the enterprises of the city of Norilsk

The influence of air emissions from the enterprises of the city of Norilsk on the vegetation cover of adjacent territories was revealed. The categories of resistance of some plant species and communities to technogenic loads have been ascertained. The protective role of overmoistening of habitats was observed for plants.