164 



ELEMENTS OF AGRICULTURE 



Early plowing enables the soil to take up and retain more 

 moisture, and also increases the activity of the soil organ- 

 isms, so that more plant-food is made available. The 

 difference between early and late spring plowing is usually 



more than the difference 



between fall and spring 



plowing. 



Quiroga found that the 



surface two feet of soil on 

 early-plowed land con- 

 no. 71. A good plow tained an average of 21.49 

 per cent of moisture for the season, while on late-plowed 

 land the average was 20.27 per cent. The soluble nitrogen 

 in parts per million of dry soil averaged 4.51 for the early- 

 plowed land and 2.83 for the late-plowed. The yields 

 of corn were 59.6 bushels and 47.4 bushels. 1 The early- 

 plowed land had more 

 moisture, more soluble 

 nitrogen, and produced 

 more grain. 



Early plowing usu- 

 ally requires more labor 

 in subsequent fitting of 

 the land. If one is 

 turning under clover, 

 or other green-manure 

 crop, the early-plowed 

 land will also receive less additional humus. 



The proper depth for plowing varies with different 

 conditions. Experiments have not yet shown the exact 



AQhio State University Bulletin, Series 8, No. 28 



FIG. 72. A four-horse gang plow. One man 

 can plow nearly as fast as two men with two- 

 horse plows. 



