Authors:

Wang Zheng, Zhang Peiyuan and Liu Xiaolie (Institute Of Geography, Chinese Academy Of Sciences)

Title:

Spatial characteristics of natural disasters in China

Publisher:

Acta Geographical Sinica. 50(3)

Date:

1995

Language:

Chinese

Classification:

1, 2B

Region:

North China

Summary:

The spatial characteristics of natural disasters in China are distributed according to Disaster actions (DA) which can be divided into four DA territories: North DA territory, South DA territory, West DA territory and the Sensitive-zone DA territory. These are displayed in a figure; a table lists the most frequent disasters for each territory. Territories are further divided into DA regions; China's 14 regions are shown on a map. China's disaster distribution is concentrated near the Qinling-Huai He line (about 34° N) The Huang He-Huai He-Hai He area has experienced huge economic losses and is considered a disasters loss center; the area between Zhengzhou and Wuhan-Dong Ting Lake is also a large disaster action center. In the border zone of Yunnan-Sichuan-Guangxi, hazards produce a large number of injuries and deaths. Disasters occur most frequently in North China, which is affected by drought, floods, landslides and earthquakes in the Hu-Line zone.

Author:

Wu Shixin

Title:

Changes toward desertification in a typical region of the middle reaches of the Tarim River during the last 30 years

Publisher:

Arid Land Geography. 16(2):82-89

Date:

1993

Language:

Chinese

Classification:

3Bd, 3D, 4Ba, 4Bc, 6Db

Region:

Xinjiang, China

Summary:

The Tarim River, situated in the southern part of Xinjiang, is the longest interior river in China. In this study a typical region in. the middle reaches of the Tarim River was selected to examine desertification changes and its causes. Desertification trends during the last 30 years are due to increased population and farming and related water storage problems. It is predicted that desertification will continue to worsen until 2001. Sand and salt layers are so thick on the surface that land conditions are no longer suitable for growing vegetation. There is an extremely urgent need to strengthen environmental management and develop new water resources in South Xinjiang.

Author:

Wu Zheng (Department of Geography, South China Normal University, Guangzhou 510631)

Title:

Research on the formation and laterization of the "old red sandy sediment" along the coast of South China

Publisher:

ACTA Geographical Sinica. 49(4):298-306

Date:

1994

Language:

Chinese

Classification:

2B, 3C, 4Ab

Region:

South China

Summary:

Semi-cement, medium-fine sand sediment with red (10 R4/8) or brown-red (2.5 YR 4/8) colour, known as "Old Red Sediment", is irregularly distributed southward along the coast of South China from Pingtan Island in Fujian province. The authors conducted field investigations and laboratory analysis to confirm that "Old Red Sandy Sediment" belongs to the coastal aeolian deposit formed in the last glacial period of late Pleistocene. This finding is based on the sediment's distribution, landform pattern, deposition and age. Experimental research also showed that the red colour of the sediment contributes to a film of red clay material on the surface of uncoloured quartz sands, which is composed of clay minerals (i.e. kaolinite), mixed with ferric oxides such as hematite and goethite. These clay minerals were formed by the weathering of minerals such as feldspar in the pale-aeolian sands under wet and hot climate conditions during the high-temperature, sub-interglacial or post-glacial period. The ferric oxides are derived from oxidized ferric-silicate minerals. Development of the "Old Red Sandy Sediment" went through two stages: the coastal aeolian deposition stage in the sub-glacial period ( lower sea level) and a weathering (oxidization) stage in the sub-interglacial or post-glacial high temperature period (higher sea level). The former is the original formation process for coastal aeolian deposits and the latter is the intense subsequent oxidization (laterization) process. The time of laterization is no more than 10 000 years.

Author:

Wu Zheng (Department of Geography, South China Normal University, Guangzhou, 510631)

Title:

Comparative study of the surface texture of quartz sand in inland deserts and coastal dunes of China

Publisher:

Journal of Desert Research. 15(3)

Date:

1995

Language:

Chinese

Classification:

2Cd, 2Eb

Region:

East of China

Summary:

This paper uses a Transmission Electronic Microscopy (TEM) analysis to make a comparative study of the surface texture of quartz sand in inland deserts to that in coastal dunes. The study shows that quartz grains in both inland deserts and coastal dunes have enhanced roundness, with the characteristic features such as dished pit (D), pockmarked pit (P), and silica (SiO²) on the surface, which represent the aeolian environment. Other characteristics such as V-shaped percussion pit (V), percussion furrow reflect the origin of protosand Material. Due to environmental (especially climate) there are differences in surface textures. (1) Sand located in inland arid areas with continental climate underwent stronger aeolian mechanical action and chemical sediment action than the coastal dune sand located in humid areas with monsoon climate. The coastal dune sand shows greater evidence of chemical corrosion than the inland desert sand. (2) Even in the same coastal dune environment, the surface texture of quartz sand in the northern temperate zone shows stronger traces of mechanical action than that in the south tropical zone; yet, the latter shows more developed chemical and mechanical action.

Author:

Wu Zheng (Geography Department, South China Normal University, Guangzhou)

Title:

A superficial view of Desertification in North China

Publisher:

Acta Geographical Sinica. 46(3)

Date:

1991

Language:

Chinese

Classification:

1, 2B

Region:

North China

Summary:

This paper presents views on Desertification process of arid, semi-arid and semi-humid areas in the North China based on research. Desertification is an environmental formation or development of a sand desert-a deterioration process in which the desert is the last or terminal result. Desertification creates a distinct geographic environment. Desertification can occur not only in "unoriginal sand desert areas" but also in original sand desert areas, because of the extension and intensification of sand desert conditions. The causes of Desertification and sand deserts in North China have been changing since the Quaternary. Changes during geological periods of the Quaternary were due to global climatic change during glacial periods and were a kind of "pure" or natural processes- climate-induced geomorphic processes. Changes due to human history belong to a "natural/man-made" process, i.e. climatic and human-induced changes are ones which are mainly controlled by climatic conditions but partly influenced by human activities. The author thinks that the sand desert in the broad semi-desert and steppe areas of the eastern part of North China, existed periodically during the geological stages of Quaternary before historical times and under went several positive and negative changes, i.e. expansive and retroactive processes and naturally stable ones. Desertification occurring during the period of human history is still in a developmental stage. A one hundred year long dry period and sharp increases in population combined with the negative effects of improper economic development are causing Desertification in North China to worsen.

Authors:

Wu Zheng and Zhong Decai

Title:

Present status and future trend of desertification in northern China

Publisher:

Journal of Desert Research. 13(1):21-27

Date:

1993

Language:

Chinese

Classification:

1, 2B, 2Ea, 3D

Region:

Northern China

Summary:

Decertified areas in northern China expanded slightly during the past 30 years. This is manifested in vegetation destruction, reduced areas of fixed sand dunes, considerably increased areas of semi-fixed and mobile sand dunes and intensified desertification processes generally. The evolutionary trend of deserts will be largely controlled by future climatic change: increased concentration of greenhouse gas CO₂ caused by human activities and global climatic variations. Precipitation in the eastern part of China may increase, which will be favourable for the alleviation or reversing of the desertification process. Drought in the western desert areas may be intensified, which will promote the further development of the desertification.

Author:

Xia Ailin (Soil and Fertilizer Institute, Xinjiang Academy of Agricultural Sciences)

Title:

Irrigation techniques over pored plastic film for oasis agriculture in Xinjiang

Publisher:

Agricultural Research in the Arid Areas. 13(1):84-89

Date:

1995

Language:

Chinese

Classification:

3Aa, 6Ca

Region:

Xinjiang

Summary:

This article shows that the practice of irrigation over pored plastic film can save 30-50 percent of irrigation water with a yield increase of over ten percent. Irrigation over pored plastic film can be widely adapted; present major applications include use with open ditches, mulched ridges or in plots. The following techniques guarantee water-saving irrigation: levelling the land, applying more base fertilizer, controlling weeds and plant heights by chemicals, increasing holes by punching and treating excessive water over pored plastic film mulching.

Author:

Xia Xuncheng

Title:

A study on the mechanism of desertification

Publisher:

Arid Zone Research. 10(1):1-14

Date:

1993

Language:

Chinese

Classification:

2A, 2B, 4Aa, 4Ab, 4Ba, 4Bb, 4Bc, 4Bd, 4Be, 5A, SB, 5C, SD

Region:

Xinjiang, Inner Mongolia

Summary:

This paper discusses the effects of environmental change during the Quaternary Period using the Taklimakan Desert in Xinjiang and Horqin Sandy Land in Inner Mongolia as study areas. Factors such as climate change, source and transportation mechanisms of sand, hydrologic characteristic and utilization methods, as well as vegetation features indicate that desertification is a comprehensive geographical and physical process resulting from the influence of both natural and human environments which causes the serious disorder and collapse of ecological balance.

Author:

Xia Xuncheng, Chen Guangting, Li Chongshun, Zhou Xingjia and Pan Borong (Institute of Desert Research Chinese Academy of Sciences. Lanzhou, 730000)

Title:

Study on the engineering techniques for oil-transporting highways in Tarim Desert

Publisher:

Journal of Desert Research. 15(1):1-9

Date:

1995

Language:

Chinese

Classification:

6Ce

Region:

Xinjiang

Summary:

The Tarim oil-transporting highway passes through the hinterland of the Taklimakan Desert, which is one of the largest mobile dune fields in the world. Geological and geomorphologic conditions are quite complex along the highway line which experiences frequent sand-raising winds and higher sand transport rates. Construction of the desert highway faced two key technical problems: how to consolidate the sandy subbase and how to control wind sand damages. Both problems have been solved through cooperative research efforts of experts from different disciplines. As to the former, a sub-grade structure consisting of vibrantly compacted subbase, thin layer gravel and a beotextile structural layer was adopted. For the latter, mechanical sand barriers, chemical mulch and biological measures were used.

Author:

Xiao Honglang

Title:

Desertification of the Shiquanhe River valley in West Qing Zang plateau

Publisher:

Arid Zone Research. 11(2):41-46

Date:

1994

Language:

Chinese

Classification:

3Bd, 4Bb, 4Bc, 4Bd, 6Da

Region:

Qing Zang plateau, China

Summary:

The Shiquanhe River valley lies in western Tibet. With increasing human economic activities and over utilization of natural resources, original landscapes have been damaged, plant coverage decreased from 40-60 percent to 10-30 percent and hydrophyte and mesophyte degraded or totally destroyed. A dry-cold and windy climate combined with a ground surface of alluvial-pluvial deposits are the main causes of wind erosion and desertification. Desertification processes in the region are related to the environmental evolution of the Qingi Zang Plateau and are manifest in three ways: (1) Aridisation. The dry and cold climate in the region gradually caused the shrub meadow dominated by Mtricaria elegans to turn into decertified meadow dominated by Caragana versicolor. Vegetation communities are developing towards xerophyte types; soil and water conservation capabilities have decreased. (2) Salinisation. Evaporation of soil instead of transpiration of vegetation has resulted in the accumulation of salts, soil exposure and severe drought; meadow soil has become meadow salty soil. (3) Desertification. Abundant sand resources and wind force conditions have made desertification the most serious environmental problem in the Shiquanhe River valley. Frequent wind erosion resulted in mobile sand forming high bracken dunes on flat sandyland, while meadow soil changed into sandy soil. It is noticeable that 85 percent of the land in the region has been subjected to the degradation processes described above. Desertification control requires measures suitable to local conditions.

Author:

Xu Feng

Title:

Control and research directions for railway sand disasters

Publisher:

Journal of Desert Research. 14(2):69-74

Date:

1994

Language:

Chinese

Classification:

6Cb

Region:

Northwest of China

Summary:

Sand damage to railways manifest in many forms, such as sand deposition on roadbeds, deflation and abrasion of machine equipment, train derailment and interruption of normal traffic transport. Different sand control systems along railway lines in the Gobi and other desert areas have been adopted in accordance with sand damage conditions. In the Shapotou section of Baotou-Lanzhou Railway sand control systems include the establishment of enclosed belts, upright fences at the front side of sand dunes, straw checkerboard barriers and irrigated forest belts along both sides of the railway. In the Shixiazi section of Ganwu Railway, where there is no water source available for irrigation, sand control systems consist entirely of straw checkerboard barriers along both sides of the railway line.

Author:

Xu Qiang (Ningxia Agricultural College)

Title:

The important role of plastic sheet cover in food production in southern mountain areas of Ningxia

Publisher:

Agricultural Research in the Arid Areas. 10(3):45-50

Date:

1992

Language:

Chinese

Classification:

3Aa, 3Ab, 6Ce

Region:

Ningxia

Summary:

Experiments using plastic sheet covers in corn cultivation were conducted between 1987-1988 in Pengyang county in the arid and semi-arid area of the southern mountain area of Ningxia. The results showed that plastic sheet cover can effectively overcome natural constraints and prolong the utilization of limited natural resources such as light, heat, water and fertilizer. Yield increases were remarkable. Extension over a large area showed a 70 percent yield increase in corn when plastic sheet cover was used.

Author:

Xu Qinyun

Title:

Key measures to regenerate air-sowed shrubs and grasses on sandy land

Publisher:

Journal of Arid Land Resources and Environment. 6(2):19-26

Date:

1992

Language:

Chinese

Classification:

6Ce

Region:

North China

Summary:

Air-sowing of shrubs and grasses on shifting sandyland in steppe or desert steppe zones is an effective method for sand control and development of animal husbandry. From 1979 to 1988, air-sowed areas had reached 53 million ha of forage grasses on Mu Us Sandy Land, Horqin Sandy Land and the eastern fringe of Tengger Desert, representing 36 million ha of regenerated decertified and degraded pastureland. Serious degeneration is taking place, however, in local air-sown areas due to crust formation on sand surfaces which prevents rainfall from seeping into the subsoil layer. The key measure to resolve this situation is to keep air-sowing areas on sand surfaces in a semi-fixed condition. This can be done by proper stock grazing, which makes use of animal trampling to destroy the crust.

Author:

Xu Shuying (Institute of Geography, Academia Sinica and the State Planning Commission, Beijing)

Title:

Classification of arid climate in China and its characteristics

Publisher:

Scientia Geographical Sinica. 11(1):1-9

Date:

1991

Language:

Chinese

Classification:

2Ea

Region:

North China

Summary:

In this paper, annual aridity coefficients, annual rainfall and accumulated temperature are used as indices for the classification of arid climate. Arid areas are divided into two great types, three patterns and 15 zones. Arid areas belong to continental climates-dry with scarce rainfall. Rainfall decreases rapidly from east (500 mm) to west (10 mm), and is concentrated during summer. Heavy rain seldom occurs, but once it does, residents often experience floods and related disasters. Wind force in the arid area is great causing sandstorms. There is less lower cloud cover and longer sunshine periods in arid areas as compared to humid areas. Air temperature is low in winter and high-in summer. The range of annual and daily air temperature variation is the largest in China. During rainy season, abundant sunshine and heat are advantageous to crop growth.