10 Maine Agricultural Experiment Station. 1920 



from the 8-20 of May. Owing to the cool, moist conditions 

 in Aroostook the vegetative period of wheat is rather extended 

 and the flowering which begins about the middle of July con- 

 tinues to about the end of July. August is the ripening month, 

 the wheat being harvested in the last week of August or the 

 first week of September. Referring to the figures in the last 

 column of Table 1 it will be seen that the highest precipitations 

 occur in May, 3.57 inches, but that the rainfall during the period 

 of ripening and harvest — August, — is only slightly over half an 

 inch or 18 per cent less than the maximum monthly rainfall 

 for the season. Rainy weather during the period of ripening 

 and harvest not only may have a detrimental effect upon the 

 appearance of grain but is associated with another feature of 

 climate, namely humidity which is known to have a distinct 

 effect upon the quality of wheat. High relative humidity as- 

 sociated with an overcast sky characterizes the weather in 

 Aroostook County towards the end of July and the first week 

 of August which period marks the first stages of the kernel 

 formation. This feature is rather unfortunate as dry weather 

 and a clear sky during the process of ripening are very essential 

 to the production of a strong, high grade wheat This humid 

 condition protracts the ripening period and delays the harvest. 

 The lengthened ripening period extending through August re- 

 sults in a further drawback as the formation of the wheat ker- 

 nel does not coincide under Aroostook conditions with the high- 

 est seasonal temperature, which marks the month of July. "While 

 from the seven year average given in Table 1 it appears that the 

 mean temperature in August is only 2 degrees lower than in 

 July, the actual difference is much greater since the amount of 

 sunlight and heat decreases in the shortening days of August. 

 Medium lafef wheat varieties when planted in the latter part of 

 May often do not mature until the first week of September 

 when frequently the first early frosts occur. 



While these are the natural limitations relative to the grow- 

 ing of strong wheat .in Aroostook, it must be admitted that the 

 climatic conditions prevailing there are favorable in regard to 

 other features of the wheat crop. Thus the wheat crop is prac- 

 tically free from insect pests, and is seldom affected with stem 

 rust. 



