4 MASS. EXPERIMENT STATION BULLETIN 450 



bogs are completely flooded during March and usually have more or less ice on 

 the water the first part of this month, it is hard to see clearly why this is so. It 

 is believed, however, that high temperatures and abundant moisture in March 

 may have the influence noted by causing an early development of the cranberry 

 fungi on the uplands around the bogs. This seems to be a more reasonable ex- 

 planation than those given tentatively at the bottom of page 23 in Bulletin 433. 

 The advancement of cranberry growth by high spring temperatures with its 

 probable effect of lengthening the period of fungus infection of the new growth 

 may also be a factor, but it seems likely that the moisture relation is most closely 

 connected with fungus development. 



The sharp difference between the effects of sunshine in February and in March 

 suggests a very fundamental change in the relation of this element from one 

 month to the other. It is believed that February sunshine is important mainly 

 as a factor in maintaining oxygen sufficiency in bog waters toward the end of the 

 winter,* while the influence of March sunshine is due to its reduction of moisture 

 from rains by increasing evaporation. The apparent effect of February sunshine 

 on cranberry production is interesting here. (See p. 7.) 



2. Injury by Heat, Sunshine, and Drouth. These factors combined in August 

 or September, with all three extreme, sometimes do immense damage to the 

 condition of the Massachusetts cranberry crop It appears from Table 1 that 

 1915, 1921, 1930, 1938, 1944, and 1947 were years in which this sort of injury 

 was severe. As none of these crops were large and half of them were very small, 

 it seems that the impairment in the condition of the fruit was accompanied by 

 considerable reductions in yield. More soft berries than usual are gathered from 

 the bogs, but generally the amount of further softening in storage as a result of 

 this injury^ is not great. Proper bog irrigation in August and September seems 

 to be the best method of prevention, for a reasonable amount of moisture in the 

 surface soil eliminates drouth and, by evaporation, lowers the temperatures tow- 

 ard the tops of the cranberry vines about 4 degrees F. under these conditions.' 

 It is believed that in New Jersey, where summer bog temperatures are consider- 

 ably higher than they are on Cape Cod, cranberries gathered from grassy areas 

 are often in definitely better condition than those grown near by without such 

 shade.'' It is easy to believe this from what has been mentioned as sometimes 

 happening on Massachusetts bogs late in the summer. The experience of cran- 

 berry growers in the State of Washington, where sprinkling systems have been 

 used on the cranberry bogs everywhere in recent j^ears, is that irrigation by 

 sprinkling on hot days prevents sun-baking of the berries and definitely im- 

 proves their storage qualities. (D. J. Crowley). 



The figures in the columns of Table 2 headed with the names of the months 

 indicate the positions relative to mican rainfall at Indian Mills, New Jersey,* 

 the precipitation of May and August being given a double weight as compared 

 with that of June, September, and October. On the whole, the summations show 

 a close enough relationship to the crop departures to be of some value in the 

 early estimation of New Jersey production. The relation of the annual rainfall 

 of the year before the crop year to the mean is also a fair though not infallible 

 index, the more rain the smaller the crop. 



* In relation to the oxygen supply, this is probably the most critical period in the long winter 



flood. 



^ When the softening is due mainly to the activity of putrefactive fungi, on the other hand, it is 

 much more likely to continue noticeably throughout the time of storage. 



« Mass. Agr. Expt. Sta. Bui. 293, p. 23, 1933. 



7 R. B. Wilcox. Proceedings of the 78th Annual Meeting of the American Cranberry Grower 

 Association. 1948, pp. 25. 28. and 32.) 



8 Mass. Agr. E.xpt. Sta. Bui. 433. p. 32, 1946. 



