THE CORN CROP IN THE UNITED STATES. 115 



PROBLEM 



1. If the early plowed land in an experiment that was carried out, 

 yielded 59.6 bushels of corn, and the late plowed land produced but 47.4 

 bushels per acre, what was the per cent, gain by early plowing? 



Deep Plowing. The practice of subsoiling has been proven 

 to be of distinct advantage in clay soils for some of the follow- 

 ing- reasons: 



1. It loosens up the structure of the subsoil. 



2. It facilitates root penetration, and increases humus content. 



3. It increases the rate and depth of percolation. 



4. It aids in the capillarity or film movement of water. 



5. It increases the capacity of the soil to hold water. 



6. It prevents washing in a hilly region. 



Deep plowing is not advisable in some of the following in- 

 stances : 



1. Where there is not a good supply of organic matter. 



2. In a poor, light, sandy soil. 



3. Where the subsoil is too wet and becomes puddled. 



4. Where the subsoil is too dry and remains loose and lumpy. 



5. In regions that are very dry. 



Methods of Cultivation. 



An examination of the rooting system of a corn plant as 

 shown in the following figure (7) will serve to illustrate the im- 

 portance of making a careful study of the important problem of 

 corn cultivation. 



1. The Ohio Experiment Station has shown that on an average for 9 

 seasons shallow cultivation of corn, one and one-half inches deep, 

 produced on an average 4 bushels more per acre and 200 pounds 

 more stover per acre than corn cultivated 4 inches deep. At that 

 rate what would be the loss to the man who cultivated 6 acres of 

 corn in a similar manner to a depth of 4 inches, if corn is worth 50c 

 a bushel and corn stover is worth $6 a ton? 



