We studied on the relationship between the yields and temperature from 1948 to 1952 obseved in the experiments of meteorological influences, as a step in estimating the barley and wheat yields in future.
Our studies are on the statistical consideration of the temperature at 10 a.m. and 2 p.m. during years from 1925 to 1951 measured at the Yokohama meteorological Station, and the relationship between the yields and temperature observed at the Ofuna Experiment Station; and the relationship between the yields and the growing processes at the Ono Experiment Station.
The results are as fallows:
1) The crops proved to have negative relationship with the average monthly temperature from November to February; positive relationship with that from March to April; and almost perfect positive relationship with the comparative difference in the two average monthly temperatures.
So that increased yields in barley crops was the cold in the winter season and warmth in spring season and the large comparative difference in the two seasons.
2) The coefficient of variability in the temperature in the growing season of barley is larger than that in summer crop season.
It is very large from December to March, especially from January to February.
So we can prove the season for the larger variation in barley. yields and the effects of the temperature from December to March (especially January to February) on the variation.
3) The relationship is more intimate between the yields and the growing speed, the ratio of the growing quantity, ect, than between the yields and the data observed at specific periods, such as the length of plants, the weight of plant body above the ground, the weight of dried matter, the length of young heads, the number of stalks, etc.
The former relationship is more intimate in later stages than earlier stages in the growing season.
It has, therefore, a negative relationship with the “akiochi” tendency.
The same tendency is observed in the relationship between the yields and temperature: more intimate relationship is found between the yields and the comparative difference in two adjoining months or in several months, than between the yields and the observed data themselves.