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一、管材 荷兰排水事业有悠久的历史,全国耕地面积有一半以上具有排水设施:荷兰土地改良排水的实践证明,在开垦改良开始阶段,一般是先挖浅的明沟(深约0.5米)排除地面水及上层土壤水,进一步则要埋设较深的暗管,提高排水标准并使排水设施永久化,以满足作物生长及农业机械化要求。由于地下排水是荷兰排水的主要任务,所以暗管排水的应用已有近300年的历史,最初是用石头或柴草在沟底回填,后来采用木箱在地下作为输送管,过了一个世纪后就以粘土管为主要形式,直到1956年以从荷兰所用的暗管仍然主要是粘土瓦管。1958年荷兰瓦芬公司研制成用于农田排水的平滑塑料排水管,从
First, the pipe Netherlands has a long history of drainage, more than half of the country’s arable land with drainage facilities: the Netherlands land improvement drainage proved that the beginning of the improvement of reclamation, generally digging shallow ditch (about 0.5 m deep) to exclude the ground Water and upper soil water. Further, deeper ducts should be buried to raise drainage standards and make drainage facilities permanent so as to meet crop growth and agricultural mechanization requirements. Since underground drainage is the main task of drainage in the Netherlands, underground drainage has been used for almost 300 years. Initially, stone or firewood was used to fill the bottom of the ditch. Later, a wooden box was used underground as a delivery pipe. A century later Clay pipes were the main forms, and until 1956 the underground pipes used in the Netherlands were still mainly clay pipes. In 1958, Vaufen, the Netherlands, developed a smooth plastic drain pipe for draining farmland