98 PHILIPPINE AGRICULTURE 



maturing, and differences of 44 bushels of maize and 3.5 

 tons of fodder in the crop from i acre. An acre is 

 about five twelfths of i hektar. 



In an experiment at Ilagan, the following yields were 



obtained: 



With yellow native maize, 22.8 hi per ha. 

 With white native, 30.6 hi per ha. 

 With horse-tooth, 41.2 hi per ha. 



Horse-tooth is the commonest European starchy 

 variety. 



FIG. 74. Philippine plow 



Preparing the Soil. Before the maize is planted, the 

 ground should be made clean and reasonably fine. On 

 good maize soil very deep plowing is unprofitable. The 

 effect of plowing to different depths was tested in Illinois. 

 On a part of the field which was worked shallowly with 

 a disk-plow, but not turned over, the yield was 56.4 

 bushels an acre. 



Plowed 5 cm deep, the yield was 59.9 bushels. 



Plowed 10 cm deep, the yield was 69.4 bushels. 



Plowed 15 cm deep, the yield was 69.3 bushels. 



Plowed 20 cm deep, the yield was 71.7 bushels. 



In this case it was unprofitable to plow more than 10 cm 

 deep. But in an experiment in Cebu, very deep plowing 

 (subsoiling) almost doubled the yield. 



