【摘要】 <正> 近二、三十年来,北半球广大地区的气候发生了显著的寒暖变化,并对农业生产造成了影响。这就促使人们对气候变化愈来愈关心,竺可桢同志曾根据动植物变迁,冬季冰雪等现象,估算了我国近5000年来冬季温度的变化。在他的方法启示下,本文主要依据春秋季节的物候现象讨论我国历史时期以来生长季长度的变迁及其对农业生产的影响。更多还原

【Abstract】 Based on the phenological and agricultural evidences from the histoical documents and meteorological records, changes in growing season during the historical time in China is discussed. Such a long period must have effect the agricultural practice which is analysed in this paper.The lengths of growth season have undergone many vicissitudes with a time scale of centuries during the historical time in China. The warm periods occured at the epoch before 11th century B. C., 8th-3th centuries and 7th- mid 10th centuries A. C. The growing season lengthened 30, 20 and 10 days longer than that of today respectively. After that came a period of cold, and the growing season were about 10-30 days shorter than today. Our analysis also shows that the length of the growing season in general becomes shorter and shorter with time. This means that there exists another fluctuation with duration of thousands of years, and there is a general phase of cooling during the historical time in China.Since the end of 19th century, the growing season became longer, and reached its second maximum in 1940s. It declineed thereafter, for example, at Shanghai, the growing season in 1920-1974 was 10 days longer than that in 1873-1917. It is shown that the growing season during the last 20-30 years is an abnormal period of warmth.Another conclution is that the lengths of the fluctuation were sufficiently long and the fluctuations were sufficiently intense to have important consequences on agriculture. The agriculture of the Lower Yangtze Valley in the Dynasties Ming and Ching and the effect of climate is also discused in this paper.更多还原