【正确答案】China Experiments with Seawater-irrigated Agriculture
Chinese scientists are experimenting on irrigating crops with seawater in vast areas of coastal provinces, in an effort to help feed its huge population bothered by a shortage of land and fresh water. Since the early 1990s, almost 300, 000 hectares of alkaline land and mudflat stretching along the country's coastline, covering Shandong, Hebei, Guangdong and Hainan provinces, have been planted with either wheat, rice or oil crops, which is unprecedented around the world. Like killing two birds with one stone, developing seawater-irrigated agriculture is believed to be a way to create more farmland and lower irrigation cost.
China's population accounts for one-fifth of the world's total, but it only has about 7% of the world's arable land. If all that extra land can be used for planting crops, 150 million tons of agricultural products could be yielded, about 30 percent of China's yearly output. In another aspect, seawater irrigation can mean a lot for China whose per capita possession of fresh water equals only about one-fourth of the world's average. Water consumption for agricultural use in China accounts for 70 percent of the nation's total, and 60 percent of the cultivated land is desperately short of water supply. Compared with the technique to turn seawater into fresh water, it would cost only one-thirtieth of the cost to bring seawater directly through canals or to plant crops directly in saline soil. Since ancient times, almost all agricultural plants have to be irrigated with fresh water. However, with crossbreeding and gene techniques, Chinese scientists have cultivated a group of halophytes capable of living in a saline environment. Employing special techniques like cloning or "pollen canal technique", scientists of the Chinese Academy of Sciences successfully induced a hereditary element of halophytes into eggplants and peppers, and produced special species that can grow in a mudflat.
So far, the experiment is moving forward smoothly from the Yellow River Delta in east China to the Pearl River Delta in south China, where wheat and rice are growing in abundance. During the past five years, Chinese agriculture has witnessed marked progress, but the Chinese government still regards it as a major priority to readjust the agricultural structure, increase farmers' income and insure food safety. Science and technology, the Chinese government believed, will be the keystone for progress in the national economy including agriculture. Now that the technical bottleneck has been conquered, China is very likely to use land irrigated with seawater on a vast scale in the 21st century.