The western regions have a broad territory and abundant resources, so their development potential is great. However, the natural conditions there are very bad -- wind and sand damage and soil erosion are serious, and desertification, which is deteriorating year by year, has become the biggest obstacle to the sustainable development of the western regions.

According to a general survey of the country, the total area of arid, semi-arid and dry sub-humid regions vulnerable to desertification has reached 3.317 million square km, accounting for 34.6 percent of the entire territory; the region already desertified has hit 2.622 million square km, covering over 400 counties in 13 provinces and autonomous regions, including Xinjiang, the Inner Mongolia, Ningxia Hui and Tibet autonomous regions, and Qinghai, Gansu, Shaanxi and Shanxi provinces, accounting for 27.3 percent of the entire territory. The desertified land in the five northwest provinces and Inner Mongolia accounts for about 80 percent of the country's total. Desertification has become a serious problem for the ecological environment of China's western regions. Sand swallows up about 2,460 sq km of land each year (especially in dry and hot river valleys).

Desertification has severely affected industrial and agricultural production as well as people's lives. It has become an important factor restraining the sustainable economic and social development of China's western regions. Desertification covers a wide area, occurs in various types and expands rapidly.

This can be seen in the following aspects: 1) The area of usable land is decreasing, and the land quality is declining. Since the founding of the People's Republic of China in 1949, some 667,000 hectare of arable land have been engulfed by sand, as well as 2.353 million hectare of grassland. In addition,105 million hectare of grassland has degenerated due to sand encroachment. The per-unit yield of grain is low and unstable; 2) The conditions for human habitation are being destroyed. In the past 30 years, 2,200 houses and 3,300 livestock sheds have been buried by drifting sand in Otog County in Inner Mongolia, and nearly 700 families have had to move elsewhere. The Minqin Oasis, on the lower reaches of the Shiyanghe River in Gansu Province, has seen an annual drop of groundwater level, bringing drinking water difficulties to over 70,000 persons and 120,000 livestock, and leaving 20,000 hectare of farm land abandoned; 3) Poverty was exacerbated and social stability was greatly affected. In 1995, the agricultural output value per capita in the western regions endangered by desertification was only 34.2 percent of the country's average level, equal to one fifth of that of the eastern regions; 4) Infrastructure construction and economic development in big and medium-sized cities, industrial and transportation facilities and national defense bases are seriously threatened. About 1,300 km of railways and nearly 30,000 km of roads are endangered by wind and sand all year round in desertified areas. Such industrial and mineral enterprises as oil, natural gas, coal, salt and alkali are greatly affected. 5) Desertification exerts a big influence over the global climate change.

The development trend of desertification in China is expanding as a whole, slowing partly and out of control in some areas. For instance, the Bashang area to the north of Beijing has seen a drift sand area increase of 89.9 percent in the past nine years. A remote-sensing investigation of the country's grassland in 1994 showed that 46.7 million hectares of grassland had been degraded within 10 years, and this trend continues at a rate of 4.7 million hectares each year. Due to long-term over-cultivation, grazing and wood-cutting, the drift sand area in the Maowusu region increased by 47.2 percent and the forestry area decreased by 76.4 percent from the end of the 1950s to the mid-1990s.

The global climate change also has a great influence on desertification. It is estimated that by 2030, the northwest regions in the arid and semi-arid zones in middle latitudes will suffer from drought more frequently, and the total area of arid regions may increase by 188,000 square km, with an annual increase of 4,600 square km.

In recent years, severe sandstorms have been appearing more frequently, more severely and with an expanding scope. This is closely related to intense human activities and changing global climate. The northwest region covers a large area where sandstorms occur frequently and bring about disasters. The intensifying sandstorms signal expanding desertification. Strong sandstorms occur suddenly and disastrously, and often bring great losses to the national economy and to people's lives. In the past two years, especially strong sandstorms afflicted northern China several times, and even reached the lower reaches of the Yangtze River, reaching an unprecedented scope. "Muddy rain" has brought great inconvenience to the people of Beijing.

It is obvious that China is one of the countries undergoing the most serious desertification problems in the world. If desertification cannot be effectively put under control, the attempts at building the sustainable development of the western regions will come to nothing.

There are some new concepts to combat desertification and guarantee the sustainable development of the central and western regions

The new concept of preventing desertification is to follow the principle of harmonious co-existence between man and nature, and to pursue sustainable development. The causes and expansion of desertification mainly result from natural factors, but irrational human activities also play an important role. These include the inappropriate use of land, increasing pressure on the presently productive land brought about by population growth and undue expansion of urbanization, faulty government policies and poverty. In the development of the western regions, new desertification problems will arise, such as the development of large areas of land, destruction of vegetation and loss of fine plant species, intensification of urbanization and sharp increase of population; increasing shortage of water resources and intensification of sand encroachment and salinization. To prevent new desertification, resuscitate part of the degraded land and realize sustainable development, the following principles should be adhered to:

First, a comprehensive plan must be drawn up to ensure harmonious co-existence between man and nature. A lot of studies and practice have proved that the present desertified land mainly resulted from reckless land use in the past. Misled by the policy of "taking grain as the key issue" in the past, large areas of forests and grasslands were turned into farm land. Of this land, 50 percent was later abandoned or became sandy land because of water shortages, wind erosion, soil poverty or salinization. Now the policy of "returning farm land to forest or grassland and covering hills with afforestation" adopted by the Chinese government is aimed at correcting the situation and reestablishing the natural balance. Combating desertification is a complicated systematic project, which needs efforts through generations and joint construction of all related departments. The most urgent task at present is to draw up a scientific and comprehensive plan for land use and desertification control, thereby achieving comprehensive effects within the system in agricultural, forestry, husbandry, and sideline production, and the social and economic sectors, obtaining the best structure and functions of the macro system and promoting favorable circulation. To achieve continuity in sustainable development, planning must be done in a way guaranteed by legislation.

Vegetation coverage rate (including trees, shrubbery and grass) is one of the important indices in evaluating ecological engineering. A rational vegetation coverage rate must be calculated and designed through careful in accordance with the different requirements for protection of the natural conditions in different regions. In areas suffering severe desertification, a rational forest (vegetation) coverage rate and appropriate forest, grass and shrub areas must be guaranteed so that a safety coefficient in combating desertification can be achieved. At the same time, the area of the arable land to be returned to forests must be arranged scientifically. What's more, necessary farming land, animal husbandry pasture and people's lives must be taken into consideration, in line with population growth.

Northwest China has the richest reserve territory, representing 33.5 percent of China's total. This is where the hope for sustainable development lies. In planning the sustainable development of the region, the core issues to be considered include low and unstable precipitation, high rate of evaporation and uneven distribution of water resources. The most important thing is to avoid wasting limited water resources and inappropriate use of land, which might lead to irreversible degeneration of the ecological system. Besides, people should ensure the ecological use of water. Experience has proved that following the principles of water and soil balance is the fundamental guarantee for the sustainable development of the northwest regions.

Second, greater efforts must be put into key projects to establish a complete desertification prevention system. China has a large area of land subject to desertification, so the task of prevention is great. To adapt to the new development situation of the western regions and greatly improve the ecological environment, the government has increased its investment in key projects such as those at the sources of the Yellow and the Yangtze rivers, where desertification is increasing rapidly, and in the eroded areas on the middle and lower reaches of the Yellow River. Relevant policies have been carried out and the preliminary work has started. If all these policies are implemented correctly, technologies are rational and management strict, the desertification will be brought under control three to five years ahead of the scheduled 2010.

Besides the national key ecological projects, such areas as Alxa, the lower reaches of the Tarim and Shiyanghe rivers and the mountainous areas in Ulanqab prefecture in the Inner Mongolia Autonomous Region also suffer serious desertification. If these areas cannot be harnessed immediately, the development of the western regions will be greatly hampered, or even fail. They have become especially dangerous areas because many people there have lost the basic conditions for subsistence, strong sandstorms occur frequently, and precious and endangered animals and plants are on the verge of extinction. As a result, the "rescue project" must be started immediately. Since it is not an easy task, high-tech measures and large amounts of investment are also needed.

The system to protect farmland or oases against wind and sand is composed of three parts:

The Front Shelterbelt: This refers to the wide band on the windward side, formed by trees and shrubs, which aims at strengthening the cohesion of the soil and weakening he force of the wind; the Sand Prevention Shelterbelt (Transit Band): This refers to the filtering zone of wind and drift sand or the depositing zone of drifting sand, which is usually a forest of several levels comprised of trees and shrubs; and the Interior Shelterbelt: This features a "narrow forest band and small network." It is the core of the prevention area and mainly protects high-yield and high-efficiency crops. Experience shows that in areas attacked by serious sandstorms, a complete prevention system can effectively protect crops, reduce sand harm, guarantee people's livelihoods and reduce losses to the minimum, while in areas suffering minor damage, it can stop dry wind, improve the environment and increase the output of crops by 20 percent.

The system to prevent water and soil erosion must be formed according to diversified landscapes and landforms, and be based on "small watershed management." Take the Loess Plateau for example: On the high ground, a band for water conservation is marked out. This is for cultivation of forest or grassland by planting trees or shrubs; in the middle is the economic fruit tree band, mainly for the planting of economic trees; on the gentle slopes of the lower middle part, agricultural crops, economic crops and forage crops with rotation of crops and grass are developed. Along the terraces shrubs and grass are planted; in river valleys or dam area there is an intensive farming band of economic crops with high-output and high-efficiency.

Third, in combination with ecological projects, industry should be developed in sandy areas to improve the incomes of peasants and herdsmen. In the harnessed or seriously harnessed areas, while perfecting ecological projects, the local people should enhance their use and development of natural resources in sandy areas, and develop plantation, animal husbandry and related high-tech industry to create the conditions for peasants and herdsmen to become fairly well-off. Only when ecological, economic and social benefits are all achieved, can the full development of northwest China be effectively promoted. Such areas as the Maowusu and Horqin arid lands, the Zhunge'er Desert and the Yulin area all have a good basis for recovery. While harnessing these areas, full utilization of natural resources should be considered, to improve economic benefits and satisfy people's demand for getting rid of poverty and becoming fairly well-off. Experience has proved that sandy areas have great development potential, and a lot of experience for success has been accumulated.

Fourth, trees and grass must be planted in a scientific and rational way.

"Selecting tree and grass species in line with local conditions" is an important principle to follow in ecological construction projects. In drought-vulnerable areas, afforestation depends greatly on the water balance. If such basic knowledge is ignored, people will see only failure, as they did in the past. Afforestation and grass planting must be based on local conditions. Species must be selected scientifically. The density of trees, types of mixed species and width of forest band must be determined rationally. In the ecological construction projects of the western developing drive, people must take the responsibility for such measures. Seedling growing is a key link, so it is suggested that shrub gardens be set up in sandy areas as gene storehouses to provide fine species for large areas of afforestation.

Northwest China is drought-vulnerable and infertile, so it lacks plant and crop breeds. Furthermore, desertification has caused the variety of species and biological resources there to deteriorate. Therefore, people must pay more attention to the protection and cultivation of biological variety, including the protection of endangered species, selecting fine local tree seeds to expand proliferation, introducing fine tree, grass, grain and fruit varieties and economic crop seedlings suitable to a dry climate, especially attaching importance to existent fine local species.

Combating desertification is a difficult task involving many aspects. Meanwhile, China is responsible for implementing international treaties and carrying out its own Combating Desertification Action Program. Enhancing the results of the latest scientific research, therefore, is of great significance for the improvement and promotion of the project of combating desertification. At present, the major problems that scientists and technicians must find an urgent solution in combating desertification are: 1. Studying the causes of desertification and setting up an optimized pattern for ecological recovery; 2. Making ecological evaluation of desertification; 3. Establishing a desertification early-warning system, i.e., a remote sensing monitoring and network system; 4. Establishing a biological basis for desertification prevention.