1
The Natural Environment
China is the third largest country in the world, second only to the Soviet Union and Canada. It has a land mass of 9.6 million square kilometers, and is thus slightly larger than the United States or Western Europe. Located in East Asia, China measures over 5,500 kilometers from north to south (36 degrees of latitude) and over 5,000 kilometers from east to west (60 degrees of longitude).1
In spite of its large size, China's agricultural land is limited. More than two-thirds of the land area consists of mountains, and about 11 percent is desert. Half of the country is arid or semiarid. As a result, only 13 percent of the land area is arable. Currently no more than 11 percent of the land is cultivated, which constitutes about 7 percent of the world's total arable land.2
Topography, climate, and soil conditions are the major determinants of land utilization and agricultural cropping patterns in China, as shall be seen in this chapter. In some areas, however, human activities have modified to some extent what nature has provided.
Topography and Rivers
Topographically, China is divided into three regions, descending from the Qinghai-Tibet Plateau in the west to the eastern coastal area like a west-east staircase (see frontispiece, p. iv).
The Qinghai-Tibet Plateau, known as "the roof of the world," is the highest and largest plateau in the world. It averages 4,000 meters above sea level and covers an area of 2.2 million square kilometers, about 23 percent of China's total land area. It is sparsely populated and most of it is unsuited to agriculture.
To the north and east of the Qinghai-Tibet Plateau, the terrain drops precipitously to the second step of the staircase, which averages between 2,000 and 1,000 meters above sea level. It consists of the Junggar, the Tarim, and the Sichuan basins, and the Inner Mongolia, the Loess, and the Yunnan-Guizhou plateaus.
Further to the east, from the northern tip of Northeast China to Guangxi in the south, lies the third step of the staircase, where the altitude of the land is less than 500 meters above sea level. This is the heartland of China's agriculture and includes, from north to south, the Northeast China Plain, the North China Plain, the middle-lower Changjiang (Yangtze River) Plain, and the Zhujiang (Pearl River) Delta. These plains constitute 12 percent of the country's total land area. Scattered among them is hilly land. In addition to being China's main granary, this region also has the greatest concentration of people, with a population density ranging from 50 to more than 200 persons per square kilometer. Off the southeastern and southern coasts of this region are the two major islands of China: Taiwan to the southeast of Fujian Province and Hainan Island south of Guangdong Province and the Guangxi Zhuang Autonomous Region (AR).
Because of the west-east descending nature of China's topography, the major rivers generally flow eastward. The two major rivers—the Changjiang and the Huanghe (Yellow River)—dissect the eastern half of the country and affect agriculture profoundly but differently.
The Changjiang is the longest river in China and the third longest in the world, having a total length of 6,300 kilometers. It drains a basin of 1.8 million square kilometers, about 19 percent of China's total area. It is the major artery of water navigation in central and eastern China and provides abundant water, about 40 percent of the total surface water flow, to irrigate farmland in the middle-lower Changjiang Plain.
The Huanghe is the second longest river in China, with a total length of 5,464 kilometers and a catchment area of more than 750,000 square kilometers. It is also the most heavily silted river in the world (thus the name Yellow River) and has wrought havoc in its floodings over the centuries. As it passes through the Loess Plateau, heavy rains wash 1.6 billion metric tons of soil annnually into the river. About 400 million tons of soil are deposited along its lower reaches to raise its riverbed by about 10 centimeters each year. As a result, in some places the river is 3 to 5 meters above the surrounding land. In the 2,000 years before 1949, there were some 1,500 dike bursts and 26 violent changes in its course.3
Since the 1950s, many conservancy projects have been built to help control the river. However, because of increased soil erosion due to accelerated deforestation and clearing of grassland along its upper and middle reaches, the rate of silting in the river has increased from about 1.3 billion metric tons a year in the early 1950s to 1.6 billion tons in 1980.4 Every cubic meter of its water carries 34 kilograms of silt.5 This high silt content makes much of the water unsuitable for irrigation because the silt would clog the irrigation canals.
In the south, the Zhujiang is the longest river (2,100 kilometers). In the Zhujiang Delta it provides irrigation water, about 20 percent of China's total surface water flow, and facilitates water transport.
Climate
China's climate is characterized by great regional and seasonal variations, due to China's great range in latitude, its monsoonal winds, and its complex togography.
China's extensive territory encompasses the frigid, temperate, subtropical, and tropical zones. The southern part of Guangdong, Yunnan, and Taiwan have a tropical climate. Heilongjiang in the northeast has long and severe winters. In between, however, the bulk of China lies in the subtropical, warm-temperate, and temperate zones. The north-south temperature difference is very great in winter. For example, the January mean temperature ranges from - 30°C in the extreme northeast to above 15°C in the southern coastal areas. The summer temperature difference is much smaller because the temperature for the whole country is relatively high. For example, the July mean temperature is about 28°C in the south and 20°C in the northeast.
Precipitation amounts also vary greatly from the south to the north. From more than 2,000 millimeters in the far south, annual precipitation diminishes to about 1,000 millimeters south of the Changjiang and on the Yunnan-Guizhou Plateau, and to between 600 and 800 millimeters in the Huanghe Valley. In the northeast, annual rainfall ranges from 400 to 1,000 millimeters.
Because China is situated at the eastern side of Asia and at the western edge of the Pacific, the interaction between the continental air mass and the oceanic air mass produces the monsoons. From October to April, high air pressure develops over Siberia as cold arctic air accumulates. As a result, the prevailing winter winds blow southward from Siberia, making a large part of China, especially North China, cold and dry. Only the southeastern coastal areas receive moisture from the tropical Pacific air mass.
From April to September, the reverse takes place. As the land mass is heated up, the air over the continent becomes warmer and thinner than that over the ocean. The moist, high-pressure Pacific air mass therefore moves toward the continent, bringing humidity and precipitation. About 86 percent of the annual precipitation of the country falls between April and September. The summer rainfall is heaviest over the southeastern provinces. As the monsoonal winds penetrate the land mass toward the northwest, the precipitation gradually decreases. In addition, the further inland one travels toward the northwest, the more the annual precipitation is concentrated in the summer season. These two factors make the north and northwest more susceptible to droughts and crop failures.
Altitude and terrain also cause climatic variations. Generally, at the same latitude, the temperature drops by 5°-6°C with every increase of 1,000 meters in altitude. Thus the temperature in the Tibet Plateau stays below 10°C even in July. The Sichuan Basin has a milder winter than regions of the same latitude in the middle and lower Changjiang Valley because it is protected by surrounding mountains from cold waves. The Qinling Mountains, the watershed between the Changjiang and the Huanghe valleys, keep cold northern air from moving further south during the winter and make it difficult for the ocean air to penetrate the northwest during the summer. Consequently, the Qinling Mountains constitute the natural dividing line between China's subtropical and warm-temperate zones. They also constitute an important dividing line for China's agricultural regions.
Soils
As in topography and climate, there are also great regional variations in soils in China. However, the different types of soils can be classified into two major groups. The first group comprises the moderately to strongly leached soils (the pedalfer soils) of the south, which are acid. The second group comprises the slightly leached and unleached calcium soils of the north (pedocals), which are rich in lime (calcium carbonate) and therefore are alkaline.6 The two groups are separated roughly by a line in an east-west direction that passes through the Qinling Mountains. This line follows closely the northern boundary of the "rice region" in which rice cultivation predominates. South of the Qinling Mountains, the soils are acid. The further south one proceeds, the more acid the soil becomes due to increasing precipitation and leaching. Traveling from the southeast toward the northwest, one passes through nine major soil regions.
1. The tropical region of south Guangdong, south Guangxi, Hainan Island, and Taiwan have highly acid red and yellow lateritic soils. Because of heavy precipitation, most of the easily soluble nutrients are leached out, and constant application of fertilizer is essential for crop growth.
2. The area between the tropical region and the lower Changjiang Basin has red and yellow podzolic soils.
3. The lower Changjiang Basin is covered with yellow podzolic soils from deposits of alluvium.
4. Sichuan, east Shanxi, and Shandong have purple and brown forest soils. Leaching in this region is moderate and a balance between acidity and alkalinity is maintained.
5. The North China Plain has yellow, naturally fertile, alluvial soils from the Huanghe, Huaihe (Huai River) and Haihe (Hai River), and loess dust blown from the northwest.
6. West of the North China Plain is the Loess Plateau of Shanxi, Shaanxi, and Gansu, in which the loess soil is yellow and chestnut and very fertile.
7. In the northeast, most of the soils are podzols and brown forest soils. It is the major forest land of China.
8. From the western part of the northeast through eastern and central Inner Mongolia are the steppes of China, with chernozem, chestnut, and brown soils. Agriculture is feasible, with irrigation, in these grasslands.
9. West of the loess land and the steppes are the great expanses of mountain desert, desert, and semidesert lands. Further northwest are the dryland and mountains of Northwest China. All these lands are dry, have some salt content, and are unsuitable for agriculture except in scattered oases where irrigation is possible. Approximately one-third of China's land is in these western and northwestern regions.
Land Utilization
Topography, climate, and soils are the major geo-environmental parameters that delineate the range of possibilities for land utilization and agricultural production. Within this range, the actual patterns of land use are determined by a number of factors, such as the food needs of the population, the level of agricultural technology, and industry's need for raw materials, which all change over time. The food needs of the population change as the size of the population and the standard of living of the society increase. The level of agricultural technology improves as a result of peasants' field experience and of research conducted in response to the agricultural needs of the society. Industry's demand for raw materials increases as industry expands. Consequently, land utilization and agricultural production will change over time, affecting the environment in the long run in many cases. For example, wasteland can be reclaimed for farming, rivers can be diverted for irritation, mountain slopes can be developed for grazing, and forests can be cleared for farming. Whether or not these changes are desirable for the society in the long run depends not only on the immediate economic cost-benefits but also on the long-term environmental consequences.
Of China's total land area, no more than 11 percent, or about 100 million hectares, are cultivated. About 80 percent of the cultivated land is planted to food crops. Of the land sown to food crops, rice paddy constitutes one-third and wheat one-fifth.7 Other major food crops are maize (corn), gaoliang (sorghum), millet, and soybean. Among the industrial crops, the most important one is cotton, followed by tobacco, sugar, peanuts, and tea. China is the world's largest producer of tobacco
The percentage of land cultivated is highest in North China where it exceeds 50 percent. A total of 47 million hectares of land, about 48 percent of the cultivated land, is irrigated, giving China the largest amount of irrigated land in the world. Most of the irrigated land is located in the south, reflecting the requirement of rice cultivation as well as the abundance of water in the south. The official target is to expand irrigated land to 60 million hectares by 1985.8
Between 1949 and 1978, about 20 million hectares of land were reclaimed for farming.9 However, almost as much arable land has been lost to urban expansion, road and factory construction, and the encroachment of deserts. The prospects for sizable increases in the amount of cultivated land are not good. Although it is estimated that from 30 to 50 million hectares of wasteland, such as marshes, tideland, and hills, can still be reclaimed for farming,10 problems of salinity and irrigation make such reclamation painfully slow and costly. Thus, the official target to reclaim over 13 million hectares of wasteland in the eight years between 1978 and 1985 seems overly ambitious.11 Furthermore, the yield on the newly reclaimed land is invariably low, so that future increases in agricultural production have to come primarily from increases in yields, rather than i...