8 



MASS. EXPERIMENT STATION BULLETIN 371 



operate, are more easily repaired, and are as reliable. Several makes 

 of propeller and reversed-turbine pumps are used (Fig. 5), and they vary 

 greatly in efficiency. Repair service is an important item to be considered 

 as well as efficiency. The pumping plants in use range in lift from 1 to 

 24 feet, averaging nearly 6 feet. Their horse power averages about 30 and 

 their capacity probably about 6000 gallons a minute. A pump delivering 

 10,000 gallons a minute will flood 14 acres in 10 hours if the bog is not 

 over a foot out of level. 



Stop-waters in bog ditches often help greatly in efficient use of limited 

 water supplies in frost flooding. 



The bog should not be shut in by high uplands and woods, for open 

 locations are less frosty, and the berries are more likely to set heavily and 

 ripen early if fully exposed to sunshine. 



Fig. 6. Cranberry Root Systems. 

 The plant to the left came from poorly drained, that to the right from well-drained land. 



The Form and Size of the Bog 



Other things being equal, small bugs pay better than large ones. Long 

 narrow bogs, after a certain size is reached, are more profitable than com- 

 pact ones. The care of large compact bogs and the harvesting of their 

 crops are disproportionatelj' costly, because it takes more time to wheel 

 sand to the center of the bog and to bring the berries from tlu- center; also, 

 most of the bog operations call for more tramping over, and consequent 

 injur}' to, the vines on large blocky areas. Another factor limiting the 

 success of large bogs is the greater prevalence of the black-headed fire- 

 worm on them. Flooding favors this insect by destroying a fungus that 

 often attacks it severely and b\' killing or driving Irom tlie bog most of its 

 enemies, such as spiders and parasites, at the same time protecting its 

 eggs from the adversities of winter. Tlie natural foes of the pest take 

 longer to reach the center of a large compact bog again in effective num- 

 bers than to reach the center of a small one. If, however, a large bog is 

 long and narrow, none of the factors mentioned are unfavorable. 



