Since the Pleistocene -- and especially during the recent two or three million years -- the
Himalayan Orogenic Movement has caused a rapid uplift of Qinghai-Tibetan Plateau from 2,000 meters to 5,000 meters in height. This dramatic uplift blocked northward warm and moist airflow from lower latitudes, created the cold Mongolia-Siberian Anticyclone, and formed the arid and semi-arid climate in northwest China. The high-pressure blast carried grains of sand in the porous sediment south-eastward and deposited them to shape deserts, sands and loess continuously from central to fringe areas in the northwest. In terms of loess deposition, the history of desertification in northwest China has been 2.6 million years.
According to Wang Tao, an academician of the Chinese Academy of Forestry, deserts and desertified lands cover 1.65 million square km (about 637,128 square miles) of China's total territory, of which those formed during geologic ages account for 77.6 percent, while those formed due to human activities make up 22.4 percent. Man-made destruction rather than geological forces is the main cause of desert encroachment in modern times. Respectively, the yearly expanding acreage of soil eroded land is 1,560 square km (around 616 square miles) from the 1950s to 1970s, 2,100 square km (around 810 square miles) from the mid-1970s to mid-1980s, 2,460 square km (around 950 square miles) during the first five years of the 1990s, and 3,436 square km (around 1,326 square miles) during the last five years of the 1990s.
Beginning with the building of shelter forests in the "Three North" (northwest, north and northeast) areas at the end of the 1970s, the implementation of Essentials of the National Desertification-control Programme from 1991 to 2000 marked that China's large-scale anti-desertification project was in full swing. Trials of turning cultivated land back into forest and grassland were made in 17 provinces and cities in 2000. More than twenty years' desertification-control results in the following conclusions: "Partial improvement along with entire deterioration" and "harnessing deserts lagging behind destruction." Based on reflections on previous work, we realize that there exist four misleading ideas in terms of anti-desertification.
In northwest China, prairies, wildernesses and deserts cover more than 90 percent of its total area. Therefore, xerophilous grass and thickets can survive in most areas of the northwest, while trees can only live on the mountain altitudes or in places supplied by subterranean, above-ground or artificial water resources.
Unfortunately, trees with a low survival rate make up the main body of the afforestation in the "Three North" areas including 4.76 million hectares (around 11.8 million acres) of dune-fixing forest and 370,000 hectares (around 913,900 acres) of field-protecting forest planted during the 1990s. The projects themselves were expensive and the maintenance and renewal of the forest difficult.
As a result, in the Hexi Corridor in Gansu Province, 1,200 km (about 746 miles) of the shelter belt in the "Three North" areas withered and died in vast stretches due to a reduction of the groundwater level and water supply difficulties; of the original 87,000 hectares (around 214,890 acres) of artificial forest in Minqin County, only a little more than 20,000 hectares (around 49,400 acres) survived.
"Much of the promised capital for the third phase of the Three North Shelterbelt Development Programme is not in place, while the fourth phase is near at hand. On some forestry farms, the more farmers planted trees, the more they lost. Since it is hard for farmers to reap profits after investing money, grass and labor, at present commercial benefits and farmers' initiative are big problems," according to a local report.
Drought-enduring grass and bushes are the vegetation most suitable to northwestern conditions. Compared with trees, grass and thickets consume less water and grow faster; meanwhile, the planting of xerophytes only needs shorter cycle period and much lower investment. In addition, planting grass and bushes can be combined with developing the breeding industry, favorable to the adjustment of agricultural structure and rapid increase in farmers' income. Nevertheless, despite the above advantages, victimized by the system, local policy and consensus, not only in the Three North Shelterbelt and Desertification-control projects but also in the current reclaiming forest and grassland from the cultivated land, cultivating herbage and bushes has been inferior to planting trees that is suitable in humid or semi-humid regions. Desertification-control in the arid and semi-arid northwest should rely mainly on the cultivation of grass and shrubs. Stressing the role of trees over grass and thickets was an arrogant and ill-thought out plan that not only contravened scientific and economic rules.
No matter whether it was formed by geological action or human activities, sandy wind moves in the sky to transport sand airborne rather than along the ground as dunes do. As the Great Wall might guard against the ancient foot soldiers' attacks but could do nothing against modern jet fighters and missiles, this form of sandy wind movement greatly limits the actual effects of the Three North shelter belt that works mainly on the ground and in a linear way. Steady and gradual improvement in local areas cannot change the whole deteriorating situation in the northwest. More than 200,000 hectares (around 494,000 acres) of improved lands in the past 20 years are of little avail compared with hundreds of millions of hectares of desertified lands. Similarly, the ongoing returning of the cultivated land back into forest and grassland only focuses on some hundred thousand hectares of cultivated land.
The problem does not lie in the evaluation of the project itself or comments on the way of gradual land improvement in terms of desertification-control. The movements of sandy wind as well as human overgrazing, cultivating and logging have occurred on a vast scale. Investing limited manpower and capital into desertification-control projects at localities or in a linear way will result in the situation of "partial improvement along with entire deterioration" and "harnessing deserts lagging behind destruction."
As the result of the strong wind centered on the cold anticyclone, from west to east, the northern part of China is divided into three belts: deserts, sands and loess. As Beijing is located on the fringe of the loess belt, the well-known sandy and dusty weather originates in Inner Mongolia, Gansu and the Ningxia Hui Autonomous Region . As pointed out in Causes and Control Means of the Sandy and Dusty Weather in North China issued by the Institute of Earth Sciences, Chinese Academy of Sciences, "accelerated desert expansion is the main cause of frequent sandstorms," and "sand origins of the disastrous sandstorm seriously threatening Beijing, Tianjin and their environs are desertified grasslands and farming lands that can be improved. Taking immediate measures in the desertified region can effectively control sand origins of the sandstorm." The newest studies made by Jin Hao et al attest to the truth of this statement.
Beijing, Tianjin and their environs as well as the Yan Mountains are located in the semi-humid deciduous broadleaf woods and forest-steppe range. Scattered sands can be formed by fluvial deposit of the Yongding River and others that go through Fengning, Xuanhua in Hebei Province and Guanting in Beijing. However, geographically speaking, climatic and vegetation conditions as well as limited sand sources in this area are different from the desertification and sand origins in the arid and semi-arid northwest. The confusion of geographical concepts led to the sensational reports of "the yellow dragon approaching Beijing with its head already over Guanting," "no distance between Beijing and the desert," "Beijing under a siege of desertification" and the argument of moving the capital. Misled by these reports, a large number of funds were invested in the "Development of Shelterbelt Circling Beijing and Tianjin" while control of the main sand origins in the northwest have been neglected.
Reforesting some of the poor and remote lands that bring on serious wind and water erosion should have been restoring the natural vegetation cover and improving local ecology. However, overemphasis on exploitation and investment of capital, grain and labor resulted -- after the "Three North Shelterbelt Development Programme" -- in another bigger national effort, "Project of Improving and Exploiting Reforested Lands." In terms of ecological improvement, compared with desertified lands, the acreage of the reforested land is just a drop in the bucket; in terms of exploitation, the currently cultivated land that has been neglected is much larger and more yielding than the poor and remote reforested land; in terms of the cause of reclaiming forest from the cultivated land, traditional extensive farming and management have not been stopped completely. Reforesting cultivated land is only a temporary solution to the issue of desertification. Putting any number of improvement projects aside, little has been done to curb the root cause of desert expansion, i.e. overgrazing, cultivating, logging and extensive farming.
The result of overgrazing, cultivating and logging is desertified lands all over the desolate steppe and wilderness area with an annual precipitation of around 200 mm (about 7.9 inches). Meanwhile, in some places seldom seen by people or sheep, 40 or 50 percent of the surface is covered by grass, bushes and gray calcium soil as guarantees against desertification. More excitingly, on the southern side of the Tengger Desert along the Baotou-Lanzhou Railway line, within a width of about one kilometer (about 3/5 of a mile) on both sides of the railway, after only four or five years' fencing and forbidding-grazing and logging, more than 40 percent of the ground has been covered by vegetation that can effectively curb the encroaching desert. In Liuyangpu Township, Yanchi County, with four or five years' air sowing of grass seeds and banning cultivation on the surface of 1,200 hectares (about 2964 acres) of movable or semi-movable sandy land, more than 60 percent is covered by the lush black desert wormwood. Growing of the black desert wormwood results in the formation of a soil crust on the ground that guarantees the movable sands are immune to wind erosion and desertification.
The ecosystem includes the combination of organism, climate, water, soil, etc. All these elements depend on each other and interact on each other in the relatively stable grand system with a self-repair mechanism. Human interferences may break the system's stability and balance. Once interfering forces dissipate or disappear, the disturbed ecosystem can gradually return to its original state by means of its self-repair function. Relying on investment, man-made projects focus on local environmental improvement; while the system's inherent self-repair mechanism can make improvement on a much larger scale. Unfortunately, in the past we have been deeply interested in man-made projects, neglecting the dramatic effects of natural forces as well as the potential commercial benefits they can bring in.
The reason for the above mistaken ideas lies in the concepts of extensive management and self-sufficient, small-scale farming plus the conviction of "man harnessing nature" promoted by the late Chairman Mao Zedong in the mid-1970s, disrespecting natural rules and lacking modern view of agricultural management. When in practice, local interests emphasizing the introduction of investment and launching of new projects lured the decision-makers to lend an ear to one side and make policies not in line with the local conditions. Based on a review of achievements and failure in previous desertification-control projects, three goals have to be attained in the future.
Over-cultivation, grazing and logging must be restrained in the source area of desertification. Stopping grazing aims to keep the carrying capacity of degraded grasslands below the limit allowed, while grazing will be forbidden in those seriously degenerated and desertified grasslands. By means of stopping cultivation, with the prerequisite of maintaining the main arable lands, those poor and remote lands with low yield and great ecological destruction will be protected from cultivation.
The purpose of stopping cultivation and grazing is to activate the ecosystem's self-repair function, so that vegetation cover and soil conditions can be improved on a large scale. They are effective rather than passive anti-desertification measures. Combining stopping cultivation with air sowing the seeds of grass and bushes in seriously desertified areas is a successful experiment that expends several hundred yuan (less than US$100) per hectare (2.47 acres) of the eroded land, only 1/50 to 1/100 of the investment for the improvement of a small river basin. This mature technology is incomparable and irreplaceable by any other improving projects.
Sheep make up the main body of the livestock in the northwest. Some110 million sheep are reared in pens annually while the number of cattle is only 5 million. Sheep have high commercial value and adapt very well to arid environments, extremely important for both the production and people's living in the northwest. On the other hand, with varying feeding habits and adaptation to different topographical features, sheep can be blamed for the destruction of ecological environment. Thus, improving ecological environment in the northwest relies highly on the sheep-grazing control. Furthermore, stopping grazing does not mean to restrict raising sheep, but to switch from grazing purely to grazing in combination with raising sheep in folds, so that the breeding industry can be shifted to the path of modern management benefiting the harmonious development of ecology and production.
Recently it was reported that in Pingluo County, Ningxia, a new way of living came out of half a million sheep. Another report said that in Wuqi County, Yan'an, Shaanxi Province, the number of cold-resistant sheep with small tails registered a sharp rise from 3,000 three years ago to 83,000 now. Under the guidance of Ningxia Academy of Agricultural Science, a sheep-raising system based on the construction of the breeding center and breeding ground for stud rams as well as sheepfolds and fodder bases is sweeping the Yinchuan Plain. By now there are almost 100 breeding farms for stud rams built voluntarily by farmers in Ningxia. The yield of the feeding corn per mu (mu is a Chinese unit of area equal to 1/6 of an acre) is close to 10 tons. The cultivation of herbage and planting areas of alfalfa is growing rapidly. The industry of developing and processing sheep products is on the upswing. According to Zhang Yingjie's experiments in Dingxi County, the average income for raising sheep in folds is 5.4 times as much as that of grazing. Agricultural zones can supply abundant feeding sources for raising sheep in folds, while in return the latter can create new opportunities for the readjustment of agricultural structure, industrial management and increase in farmers' income.
Switching from grazing to raising sheep in folds is a revolution in sheep breeding, and a vital measure to improve ecological environment in the northwest and harmonize relations between human and nature. As promoted by the government, stopping grazing and changing the traditional way of sheep breeding can improve ecological environment in source areas of the desertification, spur the progress of modernization in agriculture and increase in farmers' income, and eventually serve as a win-win strategy for ecology and production.
Based on research on two representative villages located respectively in the southern mountains and eastern eroded area in Ningxia, we find that with per capita cultivated area three or four times as many as the national average, investment one-quarter of the national average expenditure and yield one-third of the national average production, typical resource-consuming agriculture with low investment and low yield is practiced around here. Nevertheless, striking contrasts and potential positive factors lie in the fact that in these areas, the production of the first graded land per mu is equal to that of four to eight mus' third graded land, and the yield of one mu's land covered with plastic shelters is equal to that of 110 to 140 mus' third graded land. Obviously, the agricultural yield in these regions depends on the productivity of the land and investment of capital, technology and intellect rather than on land area. Transforming the traditional resource-consuming agriculture into modern agriculture is the only choice and fundamental way to improve agricultural and ecological conditions in the northwest.
Modern agriculture is a resource-saving and technology-intensive industry run by intensive management with the combination of planting, breeding, processing, trading, manufacturing and farming. The traditional way of extensive cultivation and management as well as the divorce of agriculture from animal husbandry must be replaced by the concept of modern agriculture. Only in this way, can the course of industrial management and adjustment of the agricultural structure be advanced, and a technology-industry system will come out of the combination of animal husbandry, cultivation of herbage, farming of fine breeds of livestock, water conservancy, processing of agricultural products, and management of agricultural energy.
Both irrigation- and rainfall-dependent agriculture can form an expanding agro-pastoral circle centered on villages or oases, which is the outcome of harmonized relations between human and nature, and an optimized man-made ecosystem suitable for natural and cultural environments in the northwest.
If switching from grazing to rearing sheep in folds is to tackle the problems of desertification and degeneration of the grassland at the root on a large scale, speeding up the construction of modern agriculture is to resolve the issues of ecological improvement and agricultural development in the northwest at a higher level. As fundamental measures to combat desertification, raising sheep in pens, stopping cultivating and grazing, and promoting the course of modern agriculture are emphases for the investment of capital and technology and deserve favorable policies. To use limited funds where they are needed most, the nation has to make an in-depth analysis of input and output, and appraise and compare different projects prudently and objectively.
(科技日報(bào)[Science and Technology Daily] translated by Shao Da for china.org.cn, May 11, 2002)