Author:

Chang Zhaofeng

Title:

Value analysis of several major sand-fixing measures

Publisher:

Journal of Desert Research.

15(2):

187-190

Date:

1995

Language:

Chinese

Classification:

5, 6B, 6Cb

Region:

Gansu, China

Summary:

Agriculture and animal husbandry in the Hexi corridor of Gansu province are threatened by 3.07 million ha of sandy desert. A variety of measures, including biological measures (planting trees and grasses), mechanical measure (sand fences) and a combination of these measures have been used to fix shifting sand. Sand-fixing measures can be divided into functional types: primary and secondary. The former includes sand fixation and sand block methods; the latter, increasing soil organic matter, fine particles and nutrients. The former can be expressed by an erosion-deposition coefficient, whereas the latter can be expressed by the contents of organic matter and N as well as the percentage of sand particles finer than 0.1 mm. The cost of different sand-fixing measures are calculated in order to guide selection.

Authors:

Chen Fahu, Pan Baotian, et al. (Lanzhou University)

Title:

The discovery of Palaeoeolian sand and environmental changes during the Late Pleistocene in the Lanzhou area

Publisher:

Journal of Desert Research. 10(2)

Date:

1990

Language:

Chinese

Classification:

2B, 3C, 4Aa

Region:

Gansu, China

Summary:

Palaeoeolian sand at Qinwangchuan basin in Lanzhou area has clearly inclined bedding and cross bedding structures. It was deposited as crescent dunes composed of fine and very fine sand. The sand was best sorted; it has only one peak in the grain size frequency curve and is typical aeolian sand eroded from nearby alluvial sand and Malan loess. This occurred during the late last glacial period; the desert formed between 10 Ka B.P. and 27 Ka B.P. when vegetation decreased on desert steppe and the climate was cold and dry in Lanzhou Area. This paper also discusses environmental changes during the late Pleistocene in Lanzhou area.

Author:

Chen Guangting

Title:

Desertification development trends and countermeasures in North China

Publisher:

Journal of Natural

Disasters. (1):

110-115

Date:

1992

Language:

Chinese

Classification:

1, 3D 6Aa

Region:

North China

Summary:

In the mid-1980s desertified land in Northern China was estimated to be 201 200 km². This study shows that during the past ten years decertified lands have increased by approximately 24 800 km². Average annual growth is 2 103.2 km² and the growth ratio is 1.47 percent. Contemporary desertification-prone lands accelerated in the marginal areas of Hebei Upland, Qahar Steppe and Uian Qarb Prefecture of Inner Mongolia. During the same period 45 300 km² of desertification-prone lands were rationally utilized and 2 250 km² of decertified lands rehabilitated. Decertified lands are regions with high development potential when suitable measures for restoring ecological balance. controlling desertification and rehabilitation are adopted.

Author:

Chen Hesheng

Title:

Study of the relationship between the big-climate and shelterbelt development in Shapotou area, Southeastern Tengger Desert

Publisher:

Journal of Arid Land Resources and Environment. 7(1): 51-62

Date:

1993

Language:

Chinese

Classification:

6Cd

Region:

Ningxia, China

Summary:

Shelterbelt development in semi-desert and desert zones is closely related to the climatic condition; therefore, annual precipitation levels are important to consider in shelterbelt design. It is generally accepted that areas with precipitation of 350 to 400 mm or more are suitable for planting trees, 300 to 350 mm for shrubs and 200 to 250 mm for drought resistant shrubs. Two hundred millimetres of precipitation is the lower limit for afforestation. Chinese scientists have successfully established artificial vegetation under non irrigated conditions in Shapotou area at the southeastern margin of Tengger Desert, where the annual precipitation is less than 180 mm. Observation data showed that during the initial stages the moisture content of afforested sand dunes varied between two and four percent; eight years later the figure was reduced to between one and two percent; 20 years later, 0.59 to one percent. Artificial vegetation was entirely replaced by natural vegetation.

Author:

Chen HesLeng (Institute of Desert Research, Academia Sinica, Lanzhou)

Title:

Environmental changes and rational utilization of water resources in the Keyiya River Basin

Publisher:

Journal of Desert Research. 10(3)

Date:

1990

Language:

Chinese

Classification:

2B, 6Da

Region:

North China

Summary:

Water is an important environmental resource for in hyper-arid zones. During historical periods the natural desertification process in Keyiya River valley reduced water supplies; oases became deserts. Changes in modern desert environments are caused mainly by human economic activities. Two examples are given. One is expansion of desertification in the Yutian oasis due to agricultural development and the another is human disturbance to the natural oasis in the lower reaches of the Keyiya River. Rational utilization and development of water resources can serve as a foundation for a stable ecological environment if the river valley is managed as a territorial unit. Daheyan oasis is a landscape zone with special significance for exploring environmental change and plant succession in arid zones. A natural protective zone has been established to ensure 0.1 to 0.15 billion m³ of water. Development of Yutian oasis and establishment of a protective zone are mutually supportive. Economic and environmental benefits can only be achieved if land and water resources of the valley and related agricultural activity are managed as part of an ecological unit.

Author:

Chen Longhen

Title:

Land desertification and desertification control in the lower reaches of the Heihe River

Publisher:

Journal of Arid Land Resources and Environment. 7(3.4): 61-65

Date:

1993

Language:

Chinese

Classification:

3Be, 6Da

Region:

North China

Summary:

The lower reaches of the Heihe River, also known as the Ejina River, were known as the Ruoshui River in ancient times. In recent years land desertification in this area has developed rapidly due to increasing water consumption in the upper reaches and a subsequent reduction in water supply to the lower reaches. Gaxun Lake at the eastern end of the river dried up in 1961 and the groundwater table along the river dropped by 0.5 to 3 m due to a decreasing recharge rate. Plant species along the river banks, such as Phragmites communis and Populus euphratica, died. Swamp and meadow soil on river banks turned into salinised soil (e.g. an evolution pattern of swamp soil-saline meadow soil-meadow salty soil-mineral salty soil) Irrational land use, soil moisture deterioration, wind erosion and land sandification increased and dust storms intensified. Given water's importance to desertification control, there is an urgent need to develop a water distribution plan for the entire basin.

Authors:

Chen Longheng

Title:

Land desertification and desertification control in western Ordos area

Publisher:

Journal of Arid Land Resources and Environment. 8(1): 62-71

Date:

1994

Language:

Chinese

Classification:

3 Ab, 6Ab

Region:

Inner Mongolia, China

Summary:

Using Gongkahan Township as an example. this paper addresses the land desertification issues in the western Ordos area of Inner Mongolia. This agropastoral region is situated in the transitional zone between steppe and desert with a fragile ecological environment. Mean annual rainfall is 275 to 288.5 mm, mean annual temperature is 6.3 to 5.6 °C. Land desertification is characterized by strong water and wind erosion; the former is prevalent in the western mountainous region while the latter is dominant on the middle and eastern plateau. According to severity, decertified lands in the area can be divided into slight, medium, severe and very severe. Main measures to combat desertification include eliminating cultivation to restore pasture, closing off sandyland so that grass can grow, practicing anti-deflation tillage, protecting existing vegetation and developing irrigated agriculture.

Authors:

Chen Weinan, Dong Zhibao and Yang Zuotao (Institute Of Desert Research, Chinese Academy Of Sciences, Lanzhou 730000)

Title:

Threshold velocities of sand-driving wind in the Taklimakan Desert

Publisher:

Acta Geographical Sinica. 50(4)

Date:

1995

Language:

Chinese

Classification:

2Ca, 3Aa, 6Db

Region:

Northwest of China

Summary:

Sand-driven wind is an important factor in aeolian sand movement. Proper sand control measures depend on accurate threshold velocities for estimating sand transport rates. On the basis of field observations, this paper attempts to determine fluid and impact thresholds and adapt them to different heights and time durations so that wind data obtained from meteorological observatories can be more efficiently used to study sand movement. At two metres above ground for naturally mixed sands, the instant fluid and impact threshold velocities are six to five m/s, equivalent to one minute averages of 5.2 and 4.3 m/s. Averages for ten minute durations are: fluid and impact threshold velocities of 5.7 and 4.7 m/s, respectively. Both fluid and impact thresholds have been adjusted for the height of an anemometer tower (l 1.4 m) at which the instant velocities for the former and later are 7. 8 and 6.63 m/s respectively, equivalent to 7.4 and 5.97 m/s for ten minute averages.

Authors:

Chen Yie and Liu Kang (Northwestern Institute of Botany, Chinese Academy of Sciences, Yangling 712100)

Title:

Succession of decertified steppe vegetation in the middle eastern region of Ningxia Hui Autonomous Region

Publisher:

Journal of Desert Research. 15(1):54-59

Date:

1995

Language:

Chinese

Classification:

3Aa. 4Ba, 4Bd

Region:

Ningxia Hui Autonomous Region

Summary:

The middle eastern part of Ningxia Hui Autonomous Region is located in the transitional zone between warm steppe and desert steppe on the Loess Plateau. Under the influence of a dry and windy climate, loose sandy surface and improper human economic activities, the area has become one of the most seriously decertified region in Ningxia. Although the succession stage of decertified steppe vegetation is difficult to judge, this report successfully distinguishes vegetation into two groups and four phases using cluster analytical methods. The vegetation succession of decertified steppe is different from those of sandyland vegetation and abandoned field vegetation. Cynanchum komarovii and Peganum nigellastum are indicator plants in the beginning and developmental phases of decertified steppe vegetation succession. The key issue in converting disertified vegetation into steppe vegetation is control of human activities.

Authors:

Chen Zhuchun and Li Dingshu

Title:

Microflora variation in afforested sand dune soil in Naiman banner, Horqin Sandy Land

Publisher:

Journal of Desert Research. 12(3):16-21

Date:

1992

Language:

Chinese

Classification:

2Ec, 6Ee

Region:

Inner Mongolia, China

Summary:

This study, conducted in southwestern Horqin Sandy Land, showed that microbial populations, such as bacteria, actinomyces and fungi, as well as their physiological groups in afforested sand dunes, are greater than those in shifting sand. The number of bacteria and fungi in afforested sand dunes are two to 16 times higher than those in shifting sand. Generally, the older afforested sand dunes have more bacteria and fungi as compared to newly afforested sand dunes. Microbial numbers are higher in upper layers than in sub-soil layers. In newly afforested sand dunes actinomyces are higher in number than in shifting sand, while in the older afforested sand dunes the actinomyces number less than those in newly afforested sand dunes.

Authors:

Cheng Hesheng and Kang Yaohu

Title:

Condensed water and its role in the ecological environment in Shapotou region

Publisher:

Journal of Arid Land Resources and Environment. 6(2): 63-72

Date:

1992

Language:

Chinese

Classification:

2Eb, 6Ee

Region:

Ningxia, China

Summary:

Hygroscopically condensed water, created through molecular hygroscopic and thermodynamic processes, is an important aspect of the relationship between plant growth and water balance in arid sand dune areas. During autumn nights in Shapotou area the maximum depth affected by condensed water varied from seven to nine centimetres. As a rule water condenses in the night and releases in the daytime. Micro-climatic factors, such as wind speed, temperature and relative humidity, affect both the hygroscopic condensation and the amount of condensed water. Although the quantity of condensed water in dune fields is limited, it can nourish the native plants, cryptograms and microbes and improve the biochemical characteristics of sand-fixing plants.

Authors:

Cheng Longheng and Li Fuxing

Title:

Sandstorm hazards and countermeasures in Ningxia and Alxa League, Inner Mongolia

Publisher:

Journal of Desert Research. 13(3): 8-13

Date:

1993

Language:

Chinese

Classification:

3Aa, 3Ab, 3Ba, 4Ab

Region:

Ningxia

Summary:

On 4 and 5 April and 5 and 6 May 1993, two catastrophic sandstorm events occurred in northwest China. The authors of this report made an on-the-spot investigation immediately after these sandstorms in Ningxia and Alxa League, Inner Mongolia. According to meteorological records, the mean wind velocity in northern Yinchuan during sandstorms varied from 18-25 m/s; maximum wind velocity reached 37.9 m/s. There were 31 deaths in 16 cities and counties in Ningxia. Injured persons totalled 108; 17 were reported missing and nearly 20 000 head of livestock lost. These sandstorms destroyed 10 300 ha of grain crops, 3 100 ha of cash crops, and 5 600 ha of orchards and other trees. Direct economic loss reached 90 million yuan and indirect economic loss exceeded 270 million yuan. In the Alxa League alone, 60 percent of the 175 000 km² of grassland were affected, 2 400 ha of farmland were covered by shifting sand and numerous livestock were reported missing leading to a direct economic loss of 210 million yuan.