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1974年联合国粮食会议的一个报告认为,灌溉农业几乎没有发展的余地了,这是因为适宜的土地和水已几乎全部开发完了。这一结论值得置疑。因为用来估算适宜灌溉的土壤和水的标准是很保守的,而且在估算时只考虑了所灌溉作物的常规标准和生产过程。如果利用咸水,灌溉农业就能扩大。最近的研究与计算表明,以前被认为不适合用于灌溉的水常可以被成功地用来种植作物,而且对作物与土壤没有长期的危害。采用新的作物和水管理对策能够进一步促进咸水灌溉的可行性。大量的咸水是可利用的,包括灌溉工程的排水和浅层地下水,世界上许多地区有这样的咸水,如美国、苏联、巴基斯坦、印度、埃及和澳大利亚。这部分水的利
A report of the 1974 UN Food Conference concluded that there is little scope for irrigated agriculture due to the almost complete development of suitable land and water. This conclusion is questionable. Because the criteria used to estimate soil and water suitable for irrigation are conservative, and only the conventional criteria and production processes of irrigated crops have been taken into account in the estimates. Irrigated agriculture can be expanded if salt water is used. Recent research and calculations have shown that water previously considered unsuitable for irrigation can often be successfully used to grow crops without any long-term harm to crops and soils. The introduction of new crop and water management strategies can further stimulate the viability of salt water irrigation. Lots of brackish water is available, including drainage from irrigation works and shallow groundwater such as the United States, the Soviet Union, Pakistan, India, Egypt and Australia in many parts of the world. This part of the water Lee