WEATHER AND CRANBERRY PRODUCTION 



41 



REPLACEABLE CALCIUM 



REPLACEABLE MAGNESIUM 



1^ MORRISON 

 EZl DURPHEE 

 ^M WILLIAMS 



Figure 1. 



Changes in Replaceable Calcium and Replaceable Magnesium in Three 

 Cranberry Soils following the Use of Alkaline Water. 



Summary of Conditions in Massachusetts 



A survey of the water being used for flooding cranberries in Massachusetts 

 was made during July and August 1945. With this were included a small num- 

 ber of ponds not now used in cranberry culture. The results of this survey are 

 presented in detail on pages 44-47. While this survey is not complete, the water 

 tested must be representative. It is obvious that in southeastern Massachusetts, 

 by far the largest cranberry producing region in the world, there is no water of 

 an alkalinity comparable to many found in Wisconsin. 



Most of the water in the clear ponds of Plymouth and Barnstable counties is 

 essentially rain water stored in hard sand, largely quartz sand. A long acquain- 

 tance with Cape Cod cranberry growers has developed a great respect for their 

 resourcefulness. I sincerely doubt, however, whether they could maintain their 

 bogs so free from weeds if they used alkaline water in flooding. 



Three facts regarding the Massachusetts situation seem, however, to warrant 

 special mention: the danger involved in the use of very acid water on Cape Cod; 

 the occurrence of at least two ponds which at times show relatively high pH; 

 and the fact that in other parts of New England, in regions apparently otherwise 

 suitable to cranberry culture, there exist waters of an alkalinity so great as to 

 make cranberry growing probably hazardous. 



Very Acid Water 



It has been known for some time^ that the water of certain reservoirs in Wis- 

 consin is so very acid and so low in carbonates and oxygen content that flooding 

 for the control of insects is extremely hazardous. On such bogs submergence 

 during July for as little as ten hours may kill 25 percent or more of the buds. A 

 few such reservoirs are also found in Massachusetts. These are usually charac- 

 terized by very low pH, 4.5 or below. In all cases the owners and managers of 



''Stevens, N. E., and Thompson, N. F. Factors influencing injury to cranberry plants during 

 flooding. Trans. Wis. Acad. Sci. 34:73-81. 1942. 



