Oct. 15, 1914 



Water Requirement of Plants 



41 



On the basis of the production of fruit the watermelon has proven 

 to be exceptionally efficient. The water requirement, calculated on the 

 basis of the dry matter in the melons and reduced to inclosure conditions, 

 was 915 ±39. The green fruit contained 95 per cent of water. The 

 water requirement on a green basis would therefore be 46. 



RAPE, TURNIP, CABB.^GE, AND POTATO 



Rape, turnip, cabbage, and two varieties of potato, the Irish Cobbler 

 and the McCormick (PI. VI, fig. 6), were included in the 191 3 meas- 

 urements (Table XXV). The water requirement, based on dry matter, 

 was as follows : 



Crop Water requirement 



Cabbage 539±7 



Turnip 639±3i 



Potato: 



Irish Cobbler 659±i5 



McCormick 7i7±ii 



Rape 743±7 



Cabbage and turnip are seen to have a lower water requirement than 

 potato and to rank in efficiency with oats. Of the potato varieties 

 the Irish Cobbler was the more efficient and produced the most tubers. 



The McCormick, a late-maturing variety, produced fine vines but 

 practically no tubers. The water requirement of rape was practically 

 the same as that of turnip during the same period of growth, but the 

 second crop, although not a heavy one, had a water requirement so 

 much higher than the first that the combined crop is approximately 16 

 per cent higher than for turnip. 



