近现代高邮湖沉积记录的环境变化

1 Introduction Gaoyou Lake is the third largest lake in Jiangsu Province. It lies in central Jiangsu Province, lower reaches of the Huaihe River, and west of the Jing–Hang (Beijing–Hangzhou) Grand Canal. Previous research on environmental changes of the…     

A Brief Report of the Investigation in the West Part of Tao-ho

(1) A General Statement.— The west part of Tao-ho which has become ourdominion since the Han Dynasty is still obscure for its geography. It containsnine districts of Kansu Province and two districts of Kokonor Province, andholds an important position in the development of the north-west China.     

The integrated risk assessment and zoning of meteorological disaster in Heilongjiang Province of China

This paper describes studies on the integrated risk assessment and zoning of meteorological disaster in Heilongjiang Province,in northeastern China,by using information-diffusion theory and cluster method with 35 years of summer temperature and precipitation data from 74 meteorological stations from 1971 through 2005.The information-diffusion theory has been used extensively in risk assessment,yet almost no one has done research about risk assessment by information-diffusion theory based on meteorological disaster standards.Some research results are as follows:the risk probability of low temperature and cold damage in the northern region is higher than that in the southern region;the risk probability of general low temperature and cold damage in the southwestern region is the highest;the risk probability of serious low temperature and cold damage in the northern region is the highest,followed by the central and southeast region;the high-risk region of arid disaster in Heilongjiang Province was primarily located in the southwestern,central,and southern parts of the province;the high-intensity arid disaster was located in the south-eastern region;the high-risk region of flood in Heilongjiang Province was primarily located from the southwest and then across the central part to the western part of Heilongjiang Province;the high-intensity flood disasters were located in almost every part of Heilongjiang Province.We can conclude from the integrated meteorological disaster risk zoning that the high-risk region of mete-orological disaster is primarily located in the southern and northern part of the province,the moderate-risk region is distributed in the central southern region and western region,the low-risk region is located in the eastern part,and the light-risk region is located in the central western part of Heilongjiang Province.     

ANIMAL HUSBANDRY IN SOUTH WESTERN KANSU PROVINCE CHIN

(1)The south-western Kansu Province may be divided,on the agriculthral stand point,into three rangcs,namely the crop-paddock and pure-pasture     

Permafrost in Qinghai Province: Characterization and impact on transportation construction

Through a long-term summary of highway construction in the permafrost regions of Qinghai Province, the formation conditions and distribution characteristics of permafrost and their impact on transporta...     

The 1st International Symposium on Transportation Soil Engineering in Cold Regions——A Joint Conference with the 10th SHAHUNIANTS Lecture

正(TRANSOILCOLD2013)Organized by: Qinghai Research Institute of Transportation (QRIT), Department of Transportation (DOT) of the Qinghai Province, China Beijing Jiaotong University, China University of Illinois at Urbana-Champaign, USA     

地理学与科学发展观:中国地理学会2004年学术年会报道(英文)

The Annual Meeting of the Geographical Society of China (GSC) and Cross-strait Symposium on Geography were held on December 3-5, 2004 in Guangzhou, Guangdong Province. A total of some 1500 geographical researchers and educators from Chinese mainland, Hong…     

The Agricultural Regions of Anhwei Province and their Population Density.

The Province Anhwei lies between the two great rivers of Yangtse andHwaiho. Along the Yangtse there is a narrow strip of alluvial land where riceis its most important crop. To the north of Hwaiho it forms the southern part     

The Agricultural Regions of Anhwei Province and their Population Density.

The Province Anhwei lies between the two great rivers of Yangtse andHwaiho. Along the Yangtse there is a narrow strip of alluvial land where riceis its most important crop. To the north of Hwaiho it forms the southern part     

中国自然资源学会2007年学术年会在西安召开

The 2007 Annual Academic Conference of China Society of Natural Resources (CSNR) was held on July 28–30 in Xi’an, Shaanxi Province of Northwest China. This conference was co-sponsored by CSNR and Shaanxi Normal University, and also supported by the In-     

Impact of land cover types on the soil characteristics in karst area of Chongqing

The 26 plots including natural forestland, secondary forestland, shrub-grassland, sloping cropland, artificial forest and abandoned field, were selected to discuss the impact of land cover on the soil characteristics in the three karst districts of Chongqing. The results showed that: (1) After the vegetation turned into secondary vegetation or artificial vegetation, or reclamation, soil physical properties would be degraded. In the surface-layer soil of sloping cropland, the contents of > 2 mm water-stable aggregates decreased obviously with apparent sandification. (2) The contents of soil organic matter and total nitrogen are controlled completely by vegetation type and land use intensity. The increasing trend is rather slow in the early days when over-reclamation is stopped and the land is converted to forest and pasture. (3) Herbaceous species increase and woody plants species decrease with the increase of land use intensity, therefore, the soil seed banks degrade more seriously. (4) The soil degradation index has been set up to describe the relative soil degradation degree under the conditions of different vegetation types. (5) Land cover has a significant effect on karst soil characteristics, land degradation in the karst ecosystem is essentially characterized by the different degradation of soil functions that serve as water banks, nutrient banks and soil seed banks.     

岩溶山区不同植被群落土壤生态系统特性研究

自然植被演替成为次生植被、人工林或人工开垦利用后,岩溶山地土壤物理性能退化;沙化现象明显;坡耕地土壤长时间持水供水性能、抗旱性能降低;土壤种子库中草本种子比例大,木本植物种子少,土壤种子库退化更严重。研究区土壤有机质和全N受植被类型和土地利用强度影响明显,坡耕地土壤有机质较林草地系统低,退耕还林还草后,土壤有机质含量稳定增加。与自然植被相比,人工林、次生林系统土壤有机质含量仍较低。从弃耕地→灌草坡→次生林地的演替过程中,土壤种子库生态优势度呈降低趋势,物种丰富度和多样性增加。研究结果认为,岩溶生态系统土地退化的实质是土壤作为水库、养分库和土壤种子库功能的差异退化。     

土地覆盖类型对科尔沁沙地南缘土壤有机碳储量的影响

研究了科尔沁沙地南缘土地覆盖由流动沙地向人工林地、农田及固定沙地等转变后,0~60 cm土层有机碳储量的变化。结果表明：农田土壤有机碳含量增加最明显,为流动沙地的3.97倍且相同层间差异均显著;樟子松（Pinus sylvestris var. mongolica）林地、新疆杨（Populus alba var. pyramidalis）林地、小叶锦鸡儿（Caragana microphylla）群落土壤有机碳含量较流动沙地分别增加79.78%、138.20%、73.07%,差异主要在0~20 cm土层;围封草地和中度放牧草地分别增加116.85%和133.71%,差异主要在0~40 cm土层;固定沙地比流动沙地增加49.44%,差异主要在0~20 cm土层。土地覆盖类型转变后,由于受到土壤容重的影响,土壤有机碳密度在0~20 cm土层变化较明显。8种土地覆盖类型可分为4组：CL1（农田）、CL2（新疆杨林地、围封草地、中度放牧草地）、CL3（樟子松林地、小叶锦鸡儿群落、固定沙地）和CL4（流动沙地）。另外,土壤有机碳含量和密度在土壤剖面上的分布也随着土地覆盖类型的变化而不同。     

土地利用方式对岩溶山地土壤种子库的影响

本文从种类组成、种子数量、生态优势度、物种多样性、种子分布规律和物种相似性等方面比较了重庆市岩溶低山10种不同土地利用系统的土壤种子库特点，10种土地利用类型包括耕地、弃耕地、果园、灌草坡、人工林和次生林。结果表明，研究区种子以草本为主，随土利用强度增加，种子类和数量减少，与地面农田杂草相似性增加，土壤种子库出质和量方面的锐减。从土壤种子角度说明研究区生态退化严重。     

半干旱黄土丘陵区人工植被深层土壤干化效应

科学评估不同植被恢复模式的土壤干化效应是目前黄土高原生态恢复一个亟需解决的关键问题。本文以半干旱黄土丘陵区14种典型人工植被为例,通过构建土壤水分相对亏缺指数CSWDI和样地土壤水分相对亏缺指数PCSWDI,定量评估了不同植被深层土壤干化效应。研究发现:除农地和撂荒草地外,各植被深层土壤水分均随土层深度的增加而升高,深层土壤水分含量同土层深度之间呈一元线性关系。不同人工植被深层土壤相对干化程度存在差异,以油松林地最高,杨树侧柏混交林地最低。不同植被类型受其自身蒸腾耗水、根系特征和耕作等影响,土壤干化的程度在剖面上存在差异,但总体趋势为随深度增加而降低。针阔叶植被配置模式土壤水分状况要稍好于阔叶纯林的配置模式。     

Impact of land cover changes and topography on soil quality in the Kasso catchment,Bale Mountains of southeastern Ethiopia

This study assessed land cover change and topographic elevation on selected soil quality parameters in the Kasso catchment, southeastern Ethiopia. Twenty‐seven soil samples collected from 0–30cm depth under four land cover types across three elevation gradients were analysed for selected soil quality parameters. Results indicated that soil particle size distribution is different (p<0.001) in the catchment because of the effect of land cover change and elevation. Most cultivated lands occupy lower elevations where clay accumulates as a result of its movement from higher to lower elevations. Ploughing accentuates weathering, making cultivated lands richer in finer materials. Cation exchange capacity and exchangeable magnesium and potassium negatively correlated with elevation, total nitrogen and available phosphorous. Conversion of natural vegetation to cropland contributed to changes in pH (p<0.05), exchangeable calcium (p<0.01), potassium (p<0.001), available phosphorous (p<0.01) and nitrogen (p<0.01) contents. Parameter soil degradation index results showed that soil organic carbon, nitrogen, available phosphorous and exchangeable potassium contents declined and bulk density increased because of the land cover change. This negative effect on agricultural development and environmental health of the catchment makes an integrated land resource management approach indispensable for sustaining agricultural productivity and the environmental health of the Kasso catchment.     

典型岩溶农业区土地利用变化对土壤性质的影响——以云南小江流域为例

以云南省泸西县小江典型岩溶农业流域为研究单元,分析了流域1982~2003年土地利用的变化及定点对比分析不同土地利用变化下土壤性质的变化,结果表明：小江流域1982~2003年610.12 km²的土地利用发生了变化,变化类型主要是由未利用地向耕地、林地以及林地向耕地的转变,人口的增加、社会、经济的发展和理智的生态决策是流域土地利用变化的主要原因;林地、未利用地转变为耕地后,土壤有机质、全氮、全磷含量大幅度降低,土壤pH明显升高,全钾、速效钾含量增加;短时间的退耕还林,土壤性质变化不明显;耕地转变为园地后,土壤性质得到明显的改善;而耕地转变为石漠化土地后,土壤性质发生显著变化,土壤有机质、全氮、全磷、碱解氮、速效磷含量大幅度降低,土壤pH明显升高;同时,研究表明土地利用变化对碳酸盐岩地层中发育的土壤性质的影响强度明显大于砂页岩地层中发育的土壤,表明碳酸盐岩地层中发育的土壤十分脆弱。     

卧龙自然保护区土地利用变化对土壤性质的影响

森林景观受干扰后的次生演替、人工林种植与农业耕作等在许多方面影响着土壤性质的变化。研究选取了四川卧龙自然保护区作为研究地点 ,阐述湿润高山区的土地利用方式与土壤性质之间的关系。选择了六种典型的土地利用方式加以比较 ,方差分析结果表明 ,不同土地利用之间土壤容重、全氮、有机碳、速效磷、速效钾的含量差异显著。相比之下 ,农田土壤养分含量偏低 ,而灌丛有着较高的有机碳、总氮与有效氮含量。 0～ 4 0cm土壤碳的储量变化幅度不大。综合土壤退化指数表明 ,坡耕地 ,撂荒地与人工林有土壤退化的趋势 ,而灌丛与次生林对土壤的性质有着改善的作用。人工林年龄与土壤有机碳、有机氮的含量正相关。     

塔里木河下游荒漠化过程土壤种子库特征

沿塔里木河下游荒漠河岸林,选择了荒漠化程度依次加重的5个断面,进行了土壤种子库野外萌发试验。结果表明:①在中度荒漠化区土壤种子库的物种相对丰富(11种),密度较高(892.6粒\5m-2);随着荒漠化程度的加剧,土壤种子库物种丰富度、总密度以及多样性指数呈现出明显下降的趋势;②与重度荒漠化区和中度荒漠化区相比,极度荒漠化区土壤种子库中的多年生草本和灌木密度占总密度的百分比有所增加,一年生草本百分比明显降低;③不同荒漠化程度对种子库密度的垂直分布影响不大,70%以上的种子集中在土壤表层0～2 cm深度。综合来看,随着荒漠化程度的加剧,土壤种子库的恢复潜力有所下降。     

塔里木河下游退化荒漠河岸林地上植被与土壤种子库关系初探

以塔里木河下游为研究区,选择退化程度不同的4个典型断面19个样地,利用种子萌发法进行了两年的种子库土壤萌发实验,试图就生态严重退化区的土壤种子库与地上植被的关系以及退化程度的差异对种子库特征的影响开展针对性的研究。结果显示: ①塔里木河下游土壤种子库的基本特征是:种子库密度小、物种种类组成较单一、物种的多样性低和地上植被与种子库的相似性较低;②随退化程度的加剧,土壤种子库密度明显下降、表层种子库比例升高、一年生草本占优势逐渐向多年生草本和灌木转变、地上植被与土壤种子库物种组成上差异显著;③退化过程中种子库多样性的变化比地上植被变化要迟缓,但是在植被退化演替的末期,土壤种子库的物种多样性指数衰减的幅度又明显快于地上植被的衰减幅度;④受干旱环境和严重退化的双重影响塔里木河下游土壤种子库与地上植被的关系表现出退化演替末期共有物种数的减少和相似性明显递减的特点。