320 



THE IRRIGATION AGE. 



per acre. These results are the average of fifteen tests, which were 

 made under identical conditions of soil, cultivation, and fertilization. 

 The following table brings together the estimates of the duty of 

 water in the Hawaiian Islands contained in the report of Schuyler and 

 Allardt, previously referred to, and the results of experiments made 

 at the Hawaiian Experiment Station by the writer: 



DUTY OF WATER IN HAWAIIAN ISLANDS. 



In the above table the yields of sugar per acre as given are higher 

 than stated by the plantation authorities. For Spreckelsville the 

 yields as stated were "for plant cane, 5.75 tons of sugar per acre; the 

 ratoon crop, 3^ tons per acre;" for Hamakuapoko, "5.6 tons of sugar 

 per acre for plant cane and 4 tons for ratoon crops," and for ratoon 

 crops at Kekaha "5 tons of sugar per acre for seven years." These 

 figures express the amounts of sugar per acre obtained by the mills 

 and marketed, and not the full amounts produced by the soil. As a 

 correction, and to make the figures comparable with the statement of 

 experiment station yields, 20 per cent has been added to the amounts 

 given by the plantations. This may be rather too much, but it has to 

 be remembered that the mills ten years ago did not obtain as much 

 sugar from the cane as they do to-day. However, the figures of yield 

 as given are probably a little in favor of the plantation. 



In comparing the data contained in the table it is again to be re- 

 membered that the figures furnished by the plantations state what 

 was actually being done by those plantations. The experiment-station 

 data show what has been done and what it is possible to do, where 

 the irrigation is carried out according to scientific principles and 

 where the conditions are under coutrol. Upon a large plantation the 

 conditions can not be controlled to the same extent as is possible with 

 experiments on limited areas. This in no wise lessens the force of the 

 fact that plantations are wasting huge volumes of water in their 

 practice of irrigation or removes the necessity of examining into and 

 determining the location and causes of the waste. 



The figures contained in the last column of the table show the 

 pounds of water received from rainfall and irrigation per pound of 



