Relation between the Yield of Upland Rice-Crop and the Weather Factors. Part I

Studies on the Relations between the Yield of Important Crops and the Weather Factors in Japan. No.2

Abstract

The coefficients of correlation between the yield of upland rice-crops and the weather factors (monthly mean temperature, monthly amount of rainfall and monthly total hours of sunshine) have been calculated by the method previously reported in this magazine, for each prefecture in Japan, each from April to October.
The correlation coefficients calculated are shown in tables 1, 2, 3, and they indicate that rainfall has most important influence on the yield of upland rice-crop in every prefecture, for the upland rice plant is susceptible to drought injuries.
It is noteworthy in this investigation that the coefficients of correlation between the yield and rainfall at the ear-appearing period are almost positive even in the northern parts of Japan, where summer temperature has large influence upon the yield as a limiting factor.
In a word, from the correlation coefficient calculated we see that rainy weather without wet or cold injuries is favourable for the upland ricecrop.