Relation between the Yield of Rapes and the Weather Factors. Part I

Studies on the Relations between the Yield of the Important Crops and the Weather Factors in Japan. No.5

Abstract

The coefficients of correlation between the yield of rapes and the weather factors (month'y mean temperature, month'y amount of rainfall and monthly total hours of sunshine) have been calculated by the method previously reported in this journal, for each prefecture in Japan, for each month during the cultivating period. The correlation coefficients ca'culated are shown in tables 1, 2, 3 and the following relations are recognized.
1. The correlation between the yield and the weather factors in the months during the cultivating period is generally not so conspicuous and does not indicate a certain tendency.
2. The correlation between the yield and the temperature from autumn to spring is positive in the north-eastern provinces, and negative in the other districts. It is noteworthy that the correlation between the yield and the temperature from ripening time to harvest time is negative against expectation.
3. The correlation of the yield with the rainfall indicates that the rainless weather from ripening time to flowering time is favourable for the rapes culture.
4. The correlation of the yield with the sunshine is closer than with other weather factors, and the sunshine from flowering time to harvest time has the largest influence on the yield.