ISSUES CONCERNING THE MANAGEMENT AND THE DEVELOPMENT OF ARID AND SEMIARID LAND IN CHINA

<正> The arid and semiarid land in China covers a vast area, about 3.5 million km~2(not coun-ting the Tibet Plateau),where natural resources are very aboundant. In this area, the totalsolar radiation is as high as 140--160 kilocalorie / cm~2. a. There are about 167 million ha ofvarious grasslands, accounting for nearly 60% of the national grassland area. Arable     

WATER BALANCE AND WATER LEVEL CHANGE IN QINGHAI LAKE

<正> The Qinghai Lake, the largest closed interior saline lake in China with the area of296611 km~2 and the altitude of 3000m, is located in the northeast of Tibet Plateau. It is sofar from industrial area that it is in the natural to semi-naturnal state. This means it isweakly influenced by human activities. So, the lake is a good place to investigateenvironmental and climatic changes. In fact, during last hundreds of years the water level     

THE ECOLOGICAL DISASTERS IN NINGXIA AND THE COUNTERMEASURES

<正> Ningxia lies in the midland of China, along the upper and middle of the Yellow River.The south of the region belongs to the Loess Plateau and the north of it is Part of theMongolian plateau. The main feature of the climate in the whole region is dry or half dry.The ecological enviroment is in a very delicate state and human activities have made itworse. The severe consequences are widely-spread various types of ecological disasters. All     

BASIC IDEA OF TOURIST''''S ITINERARIES IN THE ARID AREA OF CHINA——Discussion of the Methodology for Designing the Itineraries in the Arid Area

<正> The aspect discussed in the present paper should ont be identified strictly with the natu-ral and geogrophical arid areas in the whole China, but only referred to the seven provincesas Shaanxi, Gansu, Qinhai, Xinjiang and Inner Mongolia. According to the real conditions of the development of tourism which was formedobjectively in the arid areas, it is necessary to consider comprehensively the influence by the     

Hydrogen isotopic composition of plant leaf wax in response to soil moisture in an arid ecosystem of the northeast Qinghai-Tibetan Plateau,China

The hydrogen isotopic composition of plant leaf wax(δDwax) is used as an important tool for paleohydrologic reconstruction. However, the understanding of the relative importance of environmental and biological factors in determining δDwax values still remains incomplete. To identify the effects of soil moisture and plant physiology on δDwax values in an arid ecosystem, and to explore the implication of these values for paleoclimatic reconstruction, we measured δD values of soil water(δDwater) and δDwax values in surface soils along two distance transects extending from the lakeshore to wetland to dryland around Lake Qinghai and Lake Gahai on the northeast Qinghai-Tibetan Plateau. The results showed that the δDwater values were negatively correlated with soil water content(SWC)(R2=0.9166), and ranged from –67‰ to –46‰ with changes in SWC from 6.2% to 42.1% in the arid areas of the Gangcha(GCh) and Gahai(GH) transects. This indicated that evaporative D-enrichment in soil water was sensitive to soil moisture in an arid ecosystem. Although the shift from grasses to shrubs with increasing aridity occurred in the arid area of the GH transect, the δDwax values in surface soils from the arid areas of the two transects still showed a negative correlation with SWC(R2=0.6835), which may be due to the controls of primary evaporative D-enrichment in the soil water and additional transpirational D-enrichment in the leaf water on the δDwaxvalues. Our preliminary research suggested that δDwax values can potentially be applied as a paleo-humidity indicator on the northeast Qinghai-Tibetan Plateau.     

The formation age and evolution of Kumtagh Desert

The ancient aeolian sand has been regarded as an indicator for the formation and evolution of a desert in the past.Kumtagh Desert is located at the northern fringe of Qinghai-Tibet Plateau.The first integrated scientific investigation to the desert was carried out during the period of 2004-2006.Kumtagh Desert is an ideal natural model for studying the formation and evolution of the desert because the Quaternary strata containing ancient aeolian sands are widely distributed.The integrated field investigation and studies on sedimentary,chronology and palynology of typical profiles named Suosuo gully,Xiaoquan gully and gravel body with ancient aeolian sand layers showed that Kumtagh Desert was probably formed as early as 2,097.7±314.7 ka BP.During the period of 386.9±58.0 ka BP to 285.9±42.9 ka BP,the desert largely expanded and formed its modern distribution pattern.The desert was originally developed in the southwest,subsequently,expanded to the north and northeast.The sedimentary facies of Suosuo gully profile revealed that the desert experienced at least 19 cycles of advance and inverse processes of desertification with an average period of 110 ka in the Quaternary.The neotectonic movements played an important role in the formation,development and geomorphology of the desert.On one hand,the movements caused the formation of intermontane fault basin,which was further developed towards the closed drought basin,and caused the formation of natural environment.On the other hand,under the control of surrounding faults,the unique broom-shaped desert landscape was formed,and the gullies and sand ridges in this region experienced an abrupt directional change from north by west to north by east at the location of 39°45'-39°55'N.The unique landscape of gravel body that occurred widely in the northern desert was formed after 285.9±42.9 ka BP.The results in this paper provide the scientific basis for studying the formation age and evolutionary process under the dry climate and environment in the northwestern China,and the uplifting of Qinghai-Tibet Plateau as well as its responses to the global climate changes.     

ANALYSES OF THE DIFFERENCE BETWEEN IRRIGATED AND NONIRRIGATED AREA FOR LUMINOUS ENERGY UTILIZATION RATIO AND PRODUCTIVE POTENTIALITIES IN NINGXIA

<正> Situated in arid and semi-arid lands, the Ningxia Hui Autonomous Region is locatedat the middle reaches of the Yellow River. An adequate system of gravity irrigation was es-tablished in the north of Ningxia. Adding to abundant sunshine, strong solar radiation andmoderate heat, the agriculture is very developed. The south mountainous area of Ningxia, including both Yanchi and Tongxin counties,is short of rain, The vast lands cannot be irrigated. Nonirrigated agriculture and serious     

IRRIGATING WARPED SOILS——ANTHROPOGENIC SOIL IN ARID AND SEMI-ARID REGIONS OF CHINA

<正> The irrigating warped soils occur in the old irrigation areas of arid and semi-arid re-gions of China, and distributed from Zhangjiakou of Hebei province, through InnerMongolia Autonomous Region, Ningxia Hui Autonomous Region, Gansu province,Qinhai Province, down to Xinjiang Autonomous Region, including the arid subalpine rivervalleys in the western part of Tibet.     

A look into the past,present and future potential distributions of Talinopsis frutescens,a North American endemic lineage closely related to Cactaceae

Talinopsis frutescens(Anacampserotaceae,a family that is close related to Cactaceae)is a succulent species endemic to North America.The aim of this study was to explore,using Ecological Niche Modeling(ENM),changes in potential distribution ranges considering different climate scenarios:past conditions during the Last Inter Glacial(LIG)and the Last Glacial Maximum(LGM),the present and projections for 2070(RCP 2.6 to 8.5).A pattern of contraction is observed during the LIG,which agrees with other studies focused in species from arid environments.This pattern was followed by a migration towards the south during the LGM and a possible recent expansion to the north as is observed in the present scenario.All future projections show the same contraction and fragmentation patterns,resulting in three discontinuous areas:the northern part of the Chihuahuan Desert,the southern-central part of the Mexican Plateau,and the smallest one in the Tehuacán-Cuicatlán Valley.Our projections for future scenarios agree with other studies and support that global climate change tends to alter the current distribution of arid environment species.     

REGULATING THE INDUSTRIAL STRUCTURE IS AN PRINCIPAL APPROACH TO THE ENVIONMENT ADMINISTRATION IN ARID AND SEMI-ARID AREAS

<正> 1. The crux of the environment administration problem is theeconomic development As we Know that the evolution of environment is not only due to Nature itself, but al-so to human being particularly. In the course of history, the Loess Plateau in China, oncewoody and rich in plants has now become a serious soil-erosion area on which lies thou-     

STUDY ON THE INTRODUCTION OF LAWN PLANTS AND THE TECHNOLOGY OF PLANTING THEM IN NINGXIA''''S ARID AREA

<正> Ningxia lies inland in China. Its annual rainfall is from 130 mm to 380 mm. It lies inthe arid and semiarid areas of the midtemperate zone. Dry climate, sand blown by thewind, common salinization and scattered plants are the main climatic characteristics. So itis very important for the afforestation, environmental protection and management of cities     

LAND RESOURCE CHARACTERISTICS AND RATIONAL LAND-USE ARRANGEMENT FOR FARMING,FORESTRY AND ANIMAL HUSBANDRY IN “THREE NORTHS” SHELTER FOREST AREA

<正> The "Three Norths" (Northeastern China, Northern China, and Northwestern China)Shelter forest area is located in the north part of china. The area of this region occupies41% of the total area of China. This region is eager for being managed because of its fragileecological conditions. Therefore, the basic approach to realize the harmonious developmentof ecological and economic benefits is the rational arrangement of farming, forestry and pas-ure land according to the characteristics of land resources of this region.     

EVAPORATION AND WATER BALANCE IN ARID LAND——AN EXAMPIE IN TURPAN,XINJIANG,CHINA

<正> This paper discussed some observation and calculation methods of evaporation and itscharacteristics in arid land taken an example in Turpan, Xinjiang, China by using the dataobtained from July 1, 1991 to June 30, 1992 in the observation station which was settled forthe Japan-China cooperation study in the marginal area of an oasis in Turpan, Xinjiang,China. It is pointed out that due to very low water content in arid land, real evaporation de-     

Uncertainty assessment of potential evapotranspiration in arid areas,as estimated by the Penman-Monteith method

The Penman-Monteith(PM)method is the most widely used technique to estimate potential worldwide evapotranspiration.However,current research shows that there may be significant errors in the application of this method in arid areas,although questions remain as to the degree of this estimation error and how different surface conditions may affect the estimation error.To address these issues,we evaluated the uncertainty of the PM method under different underlying conditions in an arid area of Northwest China by analyzing data from 84 meteorological stations and various Moderate Resolution Imaging Spectroradiometer(MODIS)products,including land surface temperature and surface albedo.First,we found that when the PM method used air temperature to calculate the slope of the saturation vapor pressure curve,it significantly overestimated the potential evapotranspiration;the mean annual and July–August overestimation was 83.9 and 36.7 mm,respectively.Second,the PM method usually set the surface albedo to a fixed value,which led to the potential evapotranspiration being underestimated;the mean annual underestimation was 27.5 mm,while the overestimation for July to August was 5.3 mm.Third,the PM method significantly overestimated the potential evapotranspiration in the arid area.This difference in estimation was closely related to the underlying surface conditions.For the entire arid zone,the PM method overestimated the potential evapotranspiration by 33.7 mm per year,with an overestimation of 29.0 mm from July to August.The most significant overestimation was evident in the mountainous and plain nonvegetation areas,in which the annual mean overestimation reached 5%and 10%,respectively;during July,there was an estimation of 10%and 20%,respectively.Although the annual evapotranspiration of the plains with better vegetation coverage was slightly underestimated,overestimation still occurred in July and August,with a mean overestimation of approximately 5%.In order to estimate potential evapotranspiration in the arid zone,it is important that we identify a reasonable parameter with which to calibrate the PM formula,such as the slope of the saturation vapor pressure curve,and the surface albedo.We recommend that some parameters must be corrected when using PM in order to estimate potential evapotranspiration in arid regions.     

PHENOMENON OF ESTABLISHING COENOSIUM IN DESERT AND THE ECOLOGICAL RESTORATION IN THE AREA AROUND THE OASIS

<正> The area around the oasis, lying between the oasis and the natural desert and encirclesthe oasis is different from ecotone of the oasis and the desert, because it is not the trans-forming area betwen them, but it is ecological rift valley or ecological burst zone. The oasisbase will be shaked and the nature desert will be degenerative too. It is the crux of the envi-     

TOWARD THE ESTABLISHMENT OF HERBS AND CROPS ON THE LOESS PLATEAU IN CHINA

<正> 1. Introduction. The Loess Plateau is covered by the largest (580,000 km~2) and thickest (50-100m)loess deposit on earth. Before the dawn of history, abundant vegetation grew on theplateau. Traditionally, the Loess Plateau is said to be the cradle of the Chinese culture andagriculture. However, due to human impact, especially irrational activities of agricultural     

Effects of grazing intensity on seed production of Caragana stenophylla along a climatic aridity gradient in the Inner Mongolia Steppe,China

As the increases of climatic aridity and grazing intensity,shrubs play an increasingly important role in grassland ecosystem in arid and semi-arid regions,and its abundance also generally increases.However,the effects of climatic aridity and grazing intensity on sexual reproduction of shrubs in grassland remain largely unclear.In order to understand the effects of grazing intensity and climatic drought stress,and their interaction on seed production of shrub species,we examined the seed number,seed weight and seed yield of Caragana stenophylla under three grazing intensities(fenced,mild grazing and severe grazing) across a climatic aridity gradient(semi-arid,arid,very arid and intensively arid zones) in the Inner Mongolia Steppe,northern China during 2012–2013.The seed number,seed weight and seed yield gradually increased from the semi-arid to the very arid zones,but decreased from the very arid to the intensively arid zones in fenced plots.The seed number and seed yield decreased from the semi-arid to the intensively arid zones in mild and severe grazing treatment plots,therefore,grazing enhanced the suppression effect of climatic aridity on seed production of C.stenophylla.The seed number and seed yield gradually decreased as grazing intensity increased.The seed weight was highest in severe grazing plots,followed by the mild grazing plots and then the fenced plots.Precipitation varied interannually during the study period.We observed that the seed number,seed weight and seed yield were lower in the low precipitation year(2013) than in the high precipitation year(2012).As climatic drought stress increased,the negative effects of grazing on seed production of C.stenophylla also gradually increased.Our results indicated that climatic drought stress may contribute to the encroachment of C.stenophylla shrub in arid zones by promoting its seed production.However,grazing had negative effects on sexual reproduction of C.stenophylla,and the combined effects of drought stress and grazing seriously suppressed sexual reproduction of C.stenophylla in the intensively arid zone.     

Development of a large-scale remote sensing ecological index in arid areas and its application in the Aral Sea Basin

The Aral Sea Basin in Central Asia is an important geographical environment unit in the center of Eurasia.It is of great significance to the ecological protection and sustainable development of Central Asia to carry out dynamic monitoring and effective evaluation of the eco-environmental quality of the Aral Sea Basin.In this study,the arid remote sensing ecological index(ARSEI)for large-scale arid areas was developed,which coupled the information of the greenness index,the salinity index,the humidity index,the heat index,and the land degradation index of arid areas.The ARSEI was used to monitor and evaluate the eco-environmental quality of the Aral Sea Basin from 2000 to 2019.The results show that the greenness index,the humidity index and the land degradation index had a positive impact on the quality of the ecological environment in the Aral Sea Basin,while the salinity index and the heat index exerted a negative impact on the quality of the ecological environment.The eco-environmental quality of the Aral Sea Basin demonstrated a trend of initial improvement,followed by deterioration,and finally further improvement.The spatial variation of these changes was significant.From 2000 to 2019,grassland and wasteland(saline alkali land and sandy land)in the central and western parts of the basin had the worst ecological environment quality.The areas with poor ecological environment quality are mainly distributed in rivers,wetlands,and cultivated land around lakes.During the period from 2000 to 2019,except for the surrounding areas of the Aral Sea,the ecological environment quality in other areas of the Aral Sea Basin has been improved in general.The correlation coefficients between the change in the eco-environmental quality and the heat index and between the change in the eco-environmental quality and the humidity index were–0.593 and 0.524,respectively.Climate conditions and human activities have led to different combinations of heat and humidity changes in the eco-environmental quality of the Aral Sea Basin.However,human activities had a greater impact.The ARSEI can quantitatively and intuitively reflect the scale and causes of large-scale and long-time period changes of the eco-environmental quality in arid areas;it is very suitable for the study of the eco-environmental quality in arid areas.     

Changes in terrestrial surface dry and wet conditions on the Loess Plateau(China) during the last half century

This paper,using a revised Penman-Monteith model,computed the terrestrial surface humidity index of the Loess Plateau(China) based on climatic factors of monthly mean temperature,maximum temperature,minimum temperature,relative humidity,precipitation,wind speed and sunshine duration observed on the plateau from 1961 to 2008.The temporal-spatial distribution,anomaly distribution and sub-regional temporal variations of the terrestrial surface dry and wet conditions were analyzed as well.The results showed a decreasing trend in the annual average surface humidity from the southeast to the northwest in the research area.Over the period of 1961-2008,an aridification tendency appeared sharply in the central interior region of the Loess Plateau,and less sharply in the middle part of the region.The border region showed the weakest tendency of aridification.It is clear that aridification diffused in all directions from the interior region.The spatial anomaly distribution of the terrestrial surface dry and wet conditions on the Loess Plateau can be divided into three key areas:the southern,western and eastern regions.The terrestrial annual humidity index displayed a significantly descending trend and showed remarkable abrupt changes from wet to dry in the years 1967,1977 and 1979.In the above mentioned three key areas for dry and wet conditions,the terrestrial annual humidity index exhibited a fluctuation period of 3-4 years,while in the southern region,a fluctuation period of 7-8 years existed at the same time.     

THE ENVIRONMENTAL QUALITY AND RENOVATING PLAN OF THE LOESS PLATEAU AND LIUPANSHAN MOUNTAINOUS AREA IN NINGXIA

<正> 1. The environmental quality of the Loess Plateau and Liupanshan mountainous area in Ningxia The landuse structure in the studied region was very irrational in 1970s, the propor-tions covered by farming, forestry and animal husbandry are separately 50.91%, 6.32% and33.3%. Since 1980s, the farmland has been returned back to forestry and pasture so that the