WEATHER AND CRANBERRY PRODUCTION 9 



Frost Flooding and Cranben y Production 



The records provide some evidence that frequent flooding for frost protection 

 in the spring tends to reduce the crop of the year in which it occurs. Very Httle 

 such flooding preceded the great crops of 1937 and 1942 in Massachusetts. Frost 

 flooding, however, does not seem to be as important a factor as one might expect 

 from opinions held by cranberry growers and from the effect of excessive pre- 

 cipitation in May and June (Figures 8 and 9). The low temperatures in frost 

 periods probably reduce the harmful effect of the water considerably. This is 

 evidenced by the relatively high yields now obtained in frosty Wisconsin. It 

 probably explains partly the greater harm that is generally believed to be done 

 when frost floods are held over on bogs from day to day. 



Late-Holding of the Winter Flood and Cranberry Yields 



It is widely believed that late-holding of the winter water tends to reduce 

 cranberry crops, and this is borne out by the fact that extreme late-holding 

 eliminates the crop altogether. A peculiar situation in New Jersey is interesting 

 in this connection. Following recommendations made in 1916 and 1917, i^ most 

 of the growers in that State have held the winter flood almost yearly till May 10 

 or even later to control insects and for frost protection. Wilcox^^ has shown that 

 abnormally warm weather in April and early May while this water is being held 

 materially reduces the crop. Presumably this temperature relation is true of 

 all late-holding of the winter water or of long spring reflows on cranberry bogs 

 everywhere. It may be due to some restriction of respiration of the vines and 

 their roots from slow or occasional oxygen starvation under high temperatures 

 with reduced sunlight. 



Biennial Cropping 



It is very generally believed by cranberry men that the amount of the crop in 

 one year has an important influence on that of the following year. There seems 

 to be nothing in the general production records of any of the three cranberry- 

 growing areas under consideration to support this opinion. Successive cranberry 

 crops behave as though they were placed largely in separate compartments of 

 the plant economy. Effects of the weather — temperature, sunshine, and rain- 

 fall — in the year before that of the crop carry powerfully past the intervening 

 crop, thus suggesting that the products of plant synthesis affected by weather 

 must largely pass through a period or process of incubation before becoming 

 available for the production of fruit. Their more immediate use may be in the 

 growth and conditioning of the vines. On the whole, cranberry weather relations 

 in any year seem to be mostly constructive for the crop of the following year, but 

 more largely destructive for the crop more immediately in hand. 



Weather and Cranberry Keeping 



This subject has been very ably treated by Stevens, i* but important infor- 

 mation has been obtained since his findings were published and an attempt is 

 made in Tables 6 and 18 to present the main features of our present understanding 



^^Proceedings of the 47th Annual Convention, American Cranberry Growers' Association, 1916, 

 pp. 8-11; and U. S. Dept. Agr. Farmers' Bui. 860, 1917, pp. 8, 11, and 12. 



■^^Proceedings of the 70th Annual Meeting, American Cranberry Growers' Association, 1940, 

 pp. 18-21. 



l^Mass. Agr. Expt. Sta. Bui. 402, 1943, pp. 68-83. 



