【摘要】 <正> 为了合理地安排农作物的布局和种植面积,有必要首先对大范围内大自然所提供的基础条件进行比较,以便做到既能较为充分地利用这些条件,又不勉强超出这些条件所规定的可能性。本文试就主要由气象和土壤条件决定的冬小麦对水分的需求量和供应量的计算方法进行了一些初步的研究,并在此基础上根据多年气象资料和各地土壤性质作更多还原

【Abstract】 This article investigates the methods of the calculation of water requirements and supplies for winter wheat, based on the observation data of the meteorological stations, in order to compare with the situations of the natural water conditions in different climate-soil regions.Maps of distributions of precipitations, field evaporative power and balance of water repuirements and supplies for winter wheat in five provinces of the north area of China were drawn based on the data from 1951 to 1960 of the 78 meteorological stations. It is shown from these maps that most area in North China the natural supplies of water are usually insufficient for winter wheat, hence the irrigation is necessary in order to win a rather good harvest. This article furtherindicates that the dynamic component of the evaporative power(determined by wind force and air humidity) in this area accounts for a large propertion to the total eveporative power during spring and winter seasons, and that is the main factor of causing drought in the area of North China. Therefore, reforestation in the concerned areas will help to reduce this adverse condition.更多还原