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农田排水是发展灌溉可资利用的一项重要资源。一个完善的灌区,仔细计算起来,农田排水也会占到灌区用水的68%。尽管在热天还会有12—15%的蒸发消耗,这项水量为灌溉利用仍是很可观的。本文论述在干旱半干旱地区,采集沟渠水,河水,湖水和井水进行化学分析的一些结果,这有助于说明水的台盐量和化学成份在一年中的变化趋势,和在不致危害作物的情况下用于灌溉的可能性。并提到了排水中含有的可利用形式的氮。鉴于目前农业生产对于稻、麦等谷类作物和棉、果、甘蔗等经济作物大量施用化肥,排水的经济效益(肥料价值)将会愈加为人们所重视。一个完整的关于土壤和农学方面应用排水的计划可以提供类似条件从事灌溉规划的参考。作物生长需要大量水分,其中大部分消耗在蒸发和叶面蒸腾。这些水量需要由降雨、灌溉来提供。罕考克试验站调查,在最好的土壤管理和施肥技术但不灌溉的情况下,谷物平均产量是每英亩48蒲式耳。每英亩灌溉361.48方水,产量便上升为102蒲式耳,灌溉826.24方水,产量上升为127蒲式耳。我们的经验和上述报导相似。在雨水不足而又不灌溉的情况下,谷物产量降低到只有正常年景的25%。世界上有大面积的缺雨区,百分之三十的大陆是干旱和半干旱地带。这些地方的绝大部分由于气侯影响不适于农业生产。地下水越来越多地被用来补充地面水的不足。这些水的水质各地有所不同。许多地方在秋季利用了含盐量较大的水进行补充灌溉。利用海水灌溉的可能性也已引起人们的注意。大量的城市和工业污水经过处理重复用于农业或其它方面。为了农业增产把所有水源充分有效地利是起来用当任之急。因此,利用排水发展灌溉,特别是在干旱和半干旱地区,便很值得考虑。从这一点出发,进行一番调查研究,就会认识到无论何地将农田排水重复用于灌溉效益是何等之大。
Farmland drainage is an important resource for the development of irrigation resources. A well-developed irrigation area, calculated carefully, farmland drainage will account for 68% of the irrigation water. Although there is still 12-15% evaporation on hot days, this amount of water is still significant for irrigation use. This article discusses some of the results of chemical analyzes of ditch, river, lake and well water collected in arid and semi-arid regions to help illustrate the changing trend of salt and chemical composition of water over the course of the year, The possibility of crop use for irrigation. Mention is made of available forms of nitrogen contained in the drainage. In view of the current agricultural production of rice, wheat and other cereals and crops such as cotton, fruit, sugar cane and other large areas of chemical fertilizers, the economic benefits of drainage (fertilizer value) will be more and more attention. A complete plan for applying drainage in soil and agronomy can provide a reference for similar irrigation planning. Crop growth requires large amounts of water, most of which is consumed by evaporation and leaf transpiration. These amounts of water need to be provided by rainfall and irrigation. The Rhenock Experimental Station survey found that with the best soil management and fertilization techniques but no irrigation, the average grain yield was 48 bushels per acre. Irrigating 361.48 cubic meters of water per acre, yields rose to 102 bushels and 826.24 square feet of water were irrigated, yielding 127 bushels. Our experience is similar to the above story. In the case of inadequate rainfall and lack of irrigation, cereal production is reduced to only 25 per cent of the normal years. There are large areas of rain-scarred areas in the world, and 30% of the continents are arid and semi-arid areas. The vast majority of these places are not suitable for agricultural production due to the impact of climate. Groundwater is increasingly being used to supplement surface water deficiencies. The water quality varies from place to place. In autumn, salt water is used for supplementary irrigation in many places. The possibility of using seawater for irrigation has also drawn attention. Large amounts of municipal and industrial wastewater are treated repeatedly for agriculture or other purposes. In order to increase agricultural production, it is imperative that all water sources be fully and effectively utilized. Therefore, the use of drainage to develop irrigation, especially in arid and semi-arid areas, is worth considering. From this point of view, conducting some investigations and studies will recognize how great it is to reuse farmland drainage for irrigation benefits everywhere.