WEATHER AND CRANBERRY PRODUCTION 7 



The great importance of a fair, but not excessive, supply of moisture, shown 

 by these studies, suggests that too great attention can hardly be given to the 

 regulation of the water table in the cranberry bogs of Massachusetts throughout 

 the growing season. Beckwith^ found that in New Jersey the optimum for the 

 water table on unsanded bogs is about eleven inches below the bog surface. His 

 opinion that the water should be kept lower in the soil of sanded areas than in 

 that of unsanded ones seems hardly tenable in view of the relatively great capil- 

 larity of peat. It seems probable, therefore, tJmt Massachusetts cranberry growers 

 will do well, at least until more exact information is available, to keep the water 

 table during the growing season very constantly ten to twelve inches below the surface, 

 except after heavy rains when it probably will be best to drain out the ditches com- 

 pletely for a few days and then refill them to the ten-twelve inch level. This will 

 require very constant attention and, because of the fact that most bogs are not level, 

 a much more extensive use of ditch stop-waters. It appears that a lot of moisture 

 applied from below does not do the same harm to cranberry crops as excessive pre- 

 cipitation.^ 



Those using sprinkling systems should note carefully the moisture requirements 

 of cranberry bogs indicated by the effects of different amounts of monthly rainfall. 



New Jersey. — Moisture relations are evidently the great controlling influence 

 in cranberry production in New Jersey. Excessive rainfall in the growing season 

 (May, June, July, and August) of the year before that of the crop (Figures 17 

 and 18) seems to be extremely harmful and only moderately less harmful in the 

 season of the crop (Figures 19 and 20). It is impossible from the meager data 

 available concerning the character of the fruit of the New Jersey crops to reach 

 any idea as to whether the harmful effect of heavy rains is mainly physiological 

 or more largely pathological. At any rate, the findings suggest that more attention 

 to drainage might considerably improve the production of the New Jersey bogs. 

 Drouth in August (Figure 19) seems even more harmful in New Jersey than in 

 Massachusetts and its effects in other months may be largely masked by their 

 opposition to some of the effects of too much rain. 



Cranberry moisture relations seem on the whole to be decidedly more unsatis- 

 factory in New Jersey than in any of the other states in which this fruit is largely 

 grown, 



Wisconsin. — Meager precipitation in May and to a less extent in June (Fig- 

 ures 8 and 9) is evidently an important crop liability in Wisconsin. The opinion 

 of trained observers and the experience of cranberry growers indicate that this 

 is not due to the development of drouth conditions in these months. It may be 

 largely an indirect effect in which the sufficiency of water supplies for frost 

 flooding is concerned, the time of greatest frost danger following so closely the 

 long yearly period of light precipitation from late fall to mid-spring (see means at 

 end of Table 17), It also must accentuate the effect of drouth later in the growing 

 season in summers of generally light rainfall. The optimum amount of rain 

 appears to be four to five inches in May and in June and two to four inches in 

 July and in August (Figures 8 to 11). Excessive rainfall in July and August 

 seems to be nearly as harmful as it is in Massachusetts, and excessive rainfall 

 in May also has a definite effect. 



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

 1940, pp. 11-13. 



^Mass. Agr. Expt. Sta. Bui. 271, 1931, p. 250. 



