Studies on the Affects of Soil Temperature upon the Growth of Crop Plants (II) : Effects of soil temperature upon the growth of wheat varieties (1)

Abstract

The soil temperature is one of significant factors affecting the growth of plants, but no study was intended to examine the effect of soil temperature in winter period upon the growth and yield of wheat varieties. In this study, two winter wheat varieties: Konosu No. 25 and Norin No. 17 were used and seeded in the containers at Dec. 1. 1957. The soil temperature treatments were performed by placing pots in two constant temperature water tanks at outdoors maintained at about 6°C. and 11°C. in winter period (Jan. 11.-Mar. 31.) respectively, but those temperatures were rised about 5°∼6°C. during Apr. 1. to May 31. (Fig. 1) The results were as follows: 1) The growth of both top and root were retarded by low soil temperature (ca. 6°C.) and the degree of retardation in growth by low soil temperature was larger in root. 2) As the development of ears were promoted by high soil temperature (ca. 11°C.), heading, flowering and ripening times were hastened about one week by high soil temperature treatment. 3) Grain yield was significantly increased in the high soil temperature plot in Norin No. 17, but in Konosu No. 25, there was little difference between each plots. 4) From the above results, we concluded that the soil temperature in winter and early spring affects markedly on the vegetative and reproductive growth of wheat plants and there is varietal differences in the degree of retardation of growth by low soil temperature. It is supposed that the susceptibility to low soil temperature of Norin No. 17 may be related to the cold and snow resistance of this variety.