WEATHER AND CRANBERRY PRODUCTION 15 



Precipitation and the Size of Massachusetts Cranberries 



Franklin22 has pointed out that the amount of rainfall in July and August is 

 important to the size of berries in the following crop. 



Table 10 presents a month-by-month analysis of the relation of precipitation 

 to the size of berries for each of the twenty-one months directly preceding the 

 crop. 



Table 10. — Precipitation* and the Size of Massachusetts Cranberries. 



(Correlation coeficient and probable error for each month.) 



Year Before Year of Crop Year of Crop 



January + .0670 ± .1465 January + .1876 ± .1420 



February + .1173 + .145! February. - .2083 ± .1408 



March - .1634 + .1432 March... +.1243 ± .1449 



April - 2682 + .1366 April.. - .1837 + .1422 



May.... - .3904 + .1248 May + .1322 ± .1446 



June + .1394 + .1443 June + .0944 + .1459 



July - .1768 + .1426 July. + .3209 ± .1320 



August +.1301 +.1447 August... +.4287 +.1201 



September - .0988 ± .1457 September . + .1198 + .1450 



October - .2605 + .137'' 



November + .2974 + .1341 



December + .0155 + .1471 



* Averages of precipitation at Middleboro, Plymouth, and Hyannis. Mass. Mass. Agr. Expt. 

 Sta. Bui. 433, p. 30. 1946. 



Table 10«lists only one coefficient for the months of the year before the year of 

 the crop which is large enough to be considered significant, that of May. How- 

 ever, close inspection of the relation of May rainfall the year before the year of 

 the crop to the size of berries shows that the size ol the correlation coefficient is due 

 largely to the figures of one year, 1944. For this reason it seems unlikely that the 

 relation is important. 



Apparent!}' the rainfall in July and August of the crop year is more important 

 to the development of large berries than the rain of any other months in the 

 crop year. Since Franklin has already pointed out these relationships, further 

 discussion is unnecessary. 



Finally, Table 11 sets forth in detail the relation of sunshine, temperature, 

 and rainfall to the size of berries, and shows that the correlation coefficient for 

 this combination of weather elements is very great. 



Mass. Agr. Expt. Sta Bui. 433, p. 8, 1946. 



