岩手縣に於ける甘藷の收量と氣象との關係

抄録

(1) Controlling climatic factors for sweet potato yield in Iwate, are temperature in June, temperature and sun shine duration in July, and temperature, sun shine duration and amount of rainfall in September and October.
(2) The amount of rainfall in all growing period and the yield are closely related, and the regression equation by method lor least squares is as follows; y=848.4-0.34x
(3) The land temperature of every month and the yield are closely related; besids the land temperature in planting date, early or late of time which become 16.5°C, are very important.
(4) Although the single correlation coefficients are not significant, it is significant the multiple correlation coefficient of temperature with sun shine duration in planting date and fresh root differentiate date to the yield. And the-many climatic factors in the two dates constitute the organic relationes for each others.
(5) The correlation coefficient between the first. frosted day and the yield is not significant (+0.437); but the correlation of first frosted day-e to•rice yield is significant (+0.627^*)
(6) Generally, the sun shine duration in connection with the amount of rainfall and the temperature control the yield of sweet potato, and it is most abominable phenomenon for the sweet potato cultivating in this country, the Reigaigata climatic condition which usually spoken on rice cultivating in the country.