“从水所引出的……”这是一个极广阔的命题,因为它几乎无所不包,无处不有。地球面积的74％是水,人体的70％是水。洪水会给人类造成灾难,兴修水利又为人类带来利益;工业无水生产不出产品,风调雨顺会给农业以五谷丰登,如此等等,都是从水引出的结果。“收与不收在于水”农业是国民经济基础,是人类生存的物质保证,而水又是农业发展的物质基础。我们首先来看看农业生产对水的需求:据观测实验,从萌芽到结实,一公顷玉米需要水4000吨、大豆5500吨、棉花5000吨、小麦4200吨,而土壤中含水率一旦低于作物生长的需 “Derived from the water ...” This is a very vast proposition, because it is almost all-encompassing, ubiquitous. 74% of the earth’s surface is water and 70% of the human body is water. Floods can cause disasters to humankind, water conservation and human benefits; industrial production of anhydrous products, good weather will give agricultural bumper harvest, and so on, are derived from the water as a result. “Income and not income lies in the water” Agriculture is the foundation of the national economy, is the material guarantee of human existence, and water is the material basis for the development of agriculture. We first look at the demand for water from agricultural production: According to observational experiments, one hectare of corn requires 4,000 tons of water, 5,500 tons of soybeans, 5,000 tons of cotton and 4,200 tons of wheat, from a sprout to a strong one. However, once the water content in soil is lower than that of crops Growth needs