710 STATE BOARD OF AGRICULTURE. 



growiiip; nnd inatnriii<i-. Referenco to Chart IX sliows tliat the most 

 rain falls from INI ay to September, in all parts of the state, and these are 

 the months that it is most needed. Chart XVI shows the distribution 

 in Miehijj^an compared with that in other portions of the country, by 

 which it will be seen that an equally satisfactory distribution does not 

 obtain in all other sections. Occasional droughts occur in portions of 

 the state which seriously shortens yields. One of the most serious of 

 such droughts was that of Jul^^ and August, 191 G, which markedly 

 reduced the crops of corn, potatoes, beans, sugar beets and other crops 

 in most ])ortions of JMichigan. This affords a good opportunity for study- 

 ing the relationship between precipitation shortage and crop shortage, 

 and Chart XVI has been constructed to bring out this relationship. It 

 will be noted that the yields of corn and potatoes are directly propor- 

 tional to the July rainfall. With the exception of potatoes in the north- 

 ern portion of the lower peninsula the length of the lines representing 

 the crop yields are in the same proportion as the lines representing 

 rainfall in July, and this discrepancy may be accounted for by the fact 

 tliat in the heavy potato producing counties in this northern section, 

 along Lake Michigan, the rainfall was much heavier than that in the 

 interior of the state and the eastern portion. The average yield was 

 therefore enlarged in those sections thereby unduly increasing the gen- 

 eral average. In Leelanau county, for example, the rainfall for eluly 

 was about two inches and the average yield 130 bushels per acre, while 

 in Kalkaska county nearby, the rainfall in July was little over half 

 an inch, and the yield of potatoes but 20 bushels per acre. 



The yield of beans seems to be less closely related to the July rainfall 

 than the other two crops mentioned, but a closer study indicates that 

 rainfall in August is a determining factor on the yield of this crop. The 

 average July rainfall in 191G in ten counties which had the largest 

 yield of beans per acre in the state that fall, was 0.9G inches and the 

 August rainfall in the same counties 3.2G inches, while in the ten counties 

 which yielded the least the July rainfall Avas about the same as in the 

 other ten, 0.88 inches, but the August rainfall was only 2.02 inches, or 

 more than a third less than fell in the ten counties yielding the most. 

 The more or less even distribution of rain over the growing season is 

 therefore an important consideration where such a variety of crops is 

 raised. 



In at least two respects the unusual amount of cloudiness near the 

 windward shores of the lakes during the winter season, mentioned in 

 Part II, has an important bearing on agriculture. One of these is the 

 beneficial and protective influence on fruit trees over winter, as stated. 

 Were it not for this cloudy, moist atmosphere injury would more often 

 result, as it does in other sections, from drying out of the wood. Second, 

 cloudiness prevents thawing of wheat and rye fields on winter days, 

 which is injurious when followed by freezing at night. 



On the other hand the larger number of clear days over much of 

 Michigan in the summer season, as compared with adjoining states, is 

 a decided advantage to practically all crops, but especially to sugar 

 beets and fruit, producing not only larger crops but of better quality. 



The direct bearing of wind velocity and direction on crops is slight 

 and difficult to trace, but indirectly these elements play an important 

 part as they largely influence the other atmospheric conditions. 



