74 MASS. EXPERIMENT STATION BULLETIN 402 



station; the introduction of belt screens and the reconstruction of screenhouses 

 so as to permit cold berries to pf ss through a warm screening room so quickly as 

 to still remain cool ; the replacement of the barrel by the ventilated half-barrel or 

 quarter-barrel box; and some changes in bog management, notably the practice 

 of holding the winter flowage late on bogs which have shown a tendency toward 

 field rot. 



While there is, of course, no way of measuring these factors, their existence is 

 undoubted and it is entirely probable that a degree of unsoundness which would 

 have caused serious trouble in 1915, for example, might be in part overcome by 

 these methods in 1930. These changes are still going on. One of the most im- 

 portant recent changes is canning, which makes it possible to dispose of "tender" 

 berries safely and profitably. 



Precipitation in Relation to Keeping Quality 



With reference to the growth and maturing of its fruit, the growing season for 

 the cranberry falls naturally into three divisions. The period from the time the 

 winter flowage water is removed up to the last of June or first of July covers the 

 growth of the plant up to blossoming; July and August (and for the late varieties, 

 the first three weeks in September) cover the period of growth and ripening of the 

 fruit; harvest is confined almost exclusively to September and the early weeks of 

 October. In any stud\' of the weather relations of the cranberry plant, it is prob- 

 able that these divisions should be considered separately — as should the winter 

 rest period itself. 



The number of rainy days in the months during which the fruit is developing, 

 that is July and August, is apparently more closely correlated with the keeping 

 quality than is the amount of rain. An examination of Table 3 shows that 

 during the period under consideration, both July and August have shown more 

 than the normal number of days with .01 inch or more precipitation in 1914, 1915, 

 1919, 1922, 1927, and 1931. In all these years except 1927 the keeping quality 

 of the crop has been below the average. On the other hand, both July and August 

 have had less than the average number of days with .01 inch or more rain in 1913, 

 1918, 1923, 1924, 1925, 1929, 1932, and 1934. In all these years except 1929 

 the keeping quality of the crops has been better than average. The exceptions 

 are apparently explained by other factors which will be discussed below. 



On the other hand, 1920 and 1928, the years of the two soundest crops in the 

 period, were characterized by approximately the normal number of days with 

 rain for July and August — which suggests that an abundant and well-distributed 

 rainfall is not necessarily followed by an unusual amount of rot in the fruit, pro- 

 vided other factors are favorable. 



One surprising feature which has developed in this connection is the lack of 

 correlation between keeping quality and amount of rain in September. It has 

 long been believed that storing berries wet injures keeping quality and a rainy 

 harvest period is supposed to be dangerous to the crop. Yet three of the four 

 poorest years on record, 1914, 1922, and 1931, have had noticeably few rainy 

 days in September. In the fourth year, 1933, on the other hand, September had 

 15 days with rain and a total precipitation of 12.15 inches. 



Temperature in Relation to Keeping Quality 



Between climatic temperatures at certain periods and the keeping quality of 

 the crop there is a correlation so constant as to make it appear highly probable 

 that there is some causal connection. Temperature in Table 3 is expressed as a 



