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农作物生长的基本条件有四:卽空气、阳光、水份和土壤(肥料包括在内)。“旱灾”是指农作物缺乏水份,发育不良,收成减少使人民生活受到严重影响而言。因为农作物在生长期间缺乏水份,必然降低产量,严重者甚至棵粒不收,所以我们要想保障粮食丰产,不向旱灾作斗争是不行的。旱灾形成的原因一方面由於气候乾燥雨量稀少,或降雨季节不适合植物的需要。例如一般农作物整个生长过程约需水500公厘。而我国北方平均年降雨量仅4、5百公厘左右。南方多种水稻,约需水1,000公厘,平均年降雨量也多在1,000公厘以上,但这些雨量往往分配
There are four basic conditions for the growth of crops: air, sunlight, moisture and soil (fertilizer included). “Drought disaster” refers to the lack of water in crops, stunted growth, and the fact that people’s lives are seriously affected by the reduction in harvest. Because the lack of water during the growth of crops will inevitably reduce the output, and even serious crops will not be harvested. Therefore, we must ensure that the grain yields are high, and that it is not feasible to fight drought. The reasons for the formation of droughts are caused by the scarcity of dry weather and the fact that the rainfall season is not suitable for the needs of plants. For example, the general crop needs about 500 mm of water throughout its growth. The average annual rainfall in the north of China is only about 4, 5 hundred millimeters. Many kinds of rice in the south require about 1,000 millimeters of water, and the average annual rainfall is more than 1,000 millimeters. However, these rainfalls are often distributed.