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一、概述据有关方面研究,到2000年世界人口达63.5亿。按照人口统计为基础估算,全世界到2000年的灌溉面积约需扩大1.1亿到1.6亿公顷。为了保证世界人口迅速增长对粮食的需求,扩大灌溉面积和改建现有的灌溉系统是带有决定性的必要条件。近年来由于世界性的能源、水资源紧张,在地面灌溉中,探索低压管道灌溉系统的建设和运用低成本的新技术和新工艺已成为一项国际性的重要研究课题。美国自50年代以来已广泛应用低压管道系统进行灌溉水的分配。特别是普遍地采用了比较经济的轻型硬塑料管作为地下埋
I. Overview According to the research of relevant parties, by the year 2000, the world’s population reaches 6.35 billion. On a demographic basis, it is estimated that there will be an increase of 110-160 million hectares of irrigated area worldwide by the year 2000. In order to ensure the rapid growth of the world’s population for food, it is a decisive requirement for the expansion of irrigation areas and the rebuilding of existing irrigation systems. In recent years, due to the worldwide energy and water resources shortage, it has become an internationally important research topic to explore the construction of low pressure pipeline irrigation system and the application of new technology and process with low cost in surface irrigation. The United States has widely used low-pressure piping systems to distribute irrigation water since the 1950s. In particular, a relatively economical, light-weight, rigid plastic pipe is commonly used as a buried underground