Sustainable Agricultural Systems
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Sustainable Agricultural Systems

Clive A. Edwards

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eBook - ePub

Sustainable Agricultural Systems

Clive A. Edwards

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A unique look at how the adoption of sustainable farming methods is being pursued throughout the world. This comprehensive book provides clear insight into research and education needs and the many points of view that come to bear on the issue of sustainability. Essential for agricultural leaders in research, education, conservation, policy making, and anyone else interested in creating an economically and environmentally sustainable agriculture worldwide.

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CRC Press





Shi ming Luo and Chun ru Han

After a study of agriculture in China, Korea, and Japan in the early 1900s, F. H. King (1911) wrote Farmers of Forty Centuries. Since then, new forms of agricultural practice, such as organic farming (Oelhat, 1978), biodynamic agriculture (Koepf et al., 1976), natural farming (Masonabu, 1978), ecological agriculture (Worthington, 1981), and biological agriculture, have emerged in the West (Boeringa, 1980). Many methods proposed in these alternative agricultural systems are not strange to Chinese farmers. They are similar to the methods practiced in their homeland for generations. However, Chinese farmers today are using herbicides, plastic sheets, pelleted feed, tractors, hybrid seeds, and so on.
At this stage, an ecological agricultural concept, different from the Western concept, was proposed in China. An introduction to the historical background and present situation is important in understanding why the concept of ecological agriculture was proposed and how it relates to traditional Chinese agriculture and the modernization of Chinese agriculture.
The origin of agriculture in China can be traced back more than 7,000 years (Cheng, 1978). The development of that agriculture has been seriously shaped by nature and society. Those most widely practiced and recorded in ancient Chinese agricultural literature were ecologically reasonable and sustainable (Dang, 1988; Fan, 1985; Xia, 1979).

The Challenge to Chinese Agriculture

In the last century, especially in the past 30 years, the basic condition of China’s agriculture has changed greatly. The population has increased exponentially from about 400 million before 1900 to 1,041 million in 1985 (Figure 1). Representing about 22.2 percent of the world’s population, the Chinese rely on 9 percent of the world’s arable land. Worldwide, an average of 3.47 people have one hectare of arable land. In China, each hectare of arable land must support 7.5 people, which is a heavy burden.
Great efforts were made to increase cropland in the 1960s and early 1970s by terracing hilly areas, plowing grassland in semiarid areas, or enclosing muddy sea beaches along the coast. However, the rate of increase in cropland could not match the loss of cropland for nonagricultural usage and the increase in population. From 1957 to 1977, 26.7 million hectares of farmland were lost. The average farmland per person declined 1.9 percent each year, from 0.18 hectare in 1949 to about 0.13 hectare in 1983. Before the late 1970s, the ecosystem concept had not been established widely in China. Most efforts to increase cropland neglected the ecological consequences. This intensified the problems of soil erosion and desertification.
Today, of China’s 9.6 million square kilometers of land, about 10.3 percent is arable land, 33.0 percent is grassland, 12.0 percent is forest, 2.8 percent is inland water surface, 0.2 percent is seabeach, and the rest is desert or built-up areas. The eroded area has increased from 1.16 million square kilometers in the 1950s to 1.50 million square kilometers in the 1980s. More than 50 million tons of topsoil are lost each year. About 7 million hectares of cultivated land have saline-alkali soils. About 30.3 percent of the grassland is overgrazed and degenerating. Desertification reaches 17 million hectares; 29.4 percent of those deserts formed in the past 50 years. Only about 0.8 percent of the land is potentially arable (Agricultural Regionalization Committee of China, 1987). Total production increases in the past 30 years were due mainly to yield increases. For example, total grain production in 1985 was 2.87 times that in 1950, while the grain yield in 1985 was 2.82 times that in 1950. During this period, grain crop areas decreased from 114.41 million hectares in 1950 to 108.84 million hectares in 1985 (Figure 2).
Figure 1. Population growth in China, 1820–1986 (Berkin, 1969; HPRC, 1985).
Figure 2. China’s grain production, 1952–1986 (EBAYC, 1980–1987).
Since the 1950s, the Chinese have paid great attention to increasing crop yield by increasing inputs and improving varieties and cultural methods. For a long period, agricultural modernization in China meant “mechanization, electrification, chemicalization, and adequate irrigation.” Obviously, it was a model adapted from developed countries. The subsidized energy input of China’s agriculture has increased exponentially (Figure 3). From 1952 to 1982, large- and middle-sized tractors increased from 1,307 to 812,000, hand tractors increased from zero to 1,671,000, the rural electricity supply increased from 50 million kilowatt hours to 3,969 million kilowatt hours, and chemical fertilizer supplies increased from 0.3 million tons to 68.1 million tons. Pesticide production increased from 1,920 tons to 456,900 tons. The area irrigated by water pump increased from 0.3 million hectares to 25.1 million hectares (Editorial Board of Agricultural Yearbook of China, 1980–1987).
As a result of these efforts, food production did increase faster than the population growth. The total population in 1985 was 1.81 times that in 1952, while total grain production in 1985 was 2.31 times that in 1952. The nutrition of Chinese people has been improving continually (Human Population Research Center of the Chinese Academy of Science, 1985).
Can these high-input strategies be successful in the future? After analysis of the general situation, two main difficulties can be identified. First, it is difficult for China to reach the high-input levels common in developed countries. In China, national production per person in 1983 was only $230.6 U.S., whereas it was $2,655.1 in the Soviet Union, $13,887.0 in the United States, and $8,973.1 in Japan. Energy consumption per person in China is only about 9 percent of that in the United States. Although about 10 percent of the commercial energy in China is used in the agricultural sector, biological energy is still the main energy resource in rural China (Wu, 1983).
Second, the application rate of chemical fertilizers in China already is rather high (Table 1). Diminishing returns of input increases can be found in China’s production records (Table 2). It is certain that the ...