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China Pest Control
In 1987 the main method of weed and insect control continued to
be labor-intensive cultivation. Fields were carefully tended, and
a variety of biological controls, such as breeding natural enemies
of crop pests, were used. Production and use of chemical herbicides
and pesticides increased rapidly from the mid-1950s to the mid1970s , but output fell subsequently by more than half (to about
200,000 tons) because the products were relatively ineffective,
expensive, and highly toxic. Chemical pesticide use, therefore, was
low compared with use in other countries.
Seed Varieties
Improved seed varieties have contributed significantly to
improving crop yields. Highly fertilizer-responsive varieties came
into use beginning in the mid-1960s. These were comparable to those
developed outside China but were adapted to the shorter growing
season imposed by multiple cropping. Their extensive use has
complemented the large increases in fertilizer use and the increase
in irrigated area. In the mid-1970s farmers began to plant hybrid
rice, claiming yield increases of more than 20 percent. Hybrid rice
is not used elsewhere because of the amount of labor it requires,
but more than 6 million hectares of it were planted in the mid1980s , accounting for 20 percent of total rice area. The China
National Seed Company was established in 1978 to popularize
improved seed varieties; it exported Chinese vegetable seeds and
imported improved grain, cotton, forage, and oil seeds. About 5
percent of China's arable land was being used to raise seed in the
mid-1980s, and the company operated more than 2,000 seed companies
at provincial, prefectural, and county levels.
Data as of July 1987
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