XIX 



MECHANICAL PRINCIPLES OF THE PLOW 



TILLAGE is Manure," says Jethro Tull. Kropotkin, 

 the famous Russian author exile, found that minute 

 pulverization paid so well in crop returns that he 

 could afford to lift and carry the earth from his 

 garden to a grinding machine and back again. The late Dr. 

 Seaman A. Knapp, in reviewing the gains secured by applying 

 modern methods and machinery to the primitive agriculture of 

 the South, stated that the best seedbed added 100 per cent., the 

 best cultivation 50 per cent., and the best seed only 50 per cent, 

 to the crop as compared with average practice. The profit was 

 increased tenfold where the yield became threefold. Tillage 

 all but takes the place of moisture in dry farming, and is 

 undoubtedly the cornerstone of good farming everywhere. 



Pulverization,that is,the securing of proper physical condition 

 of the soil by stirring or otherwise, is claimed by most writers 

 to be the primary object of tillage. Checking the growth of, 

 and burying, undesirable vegetation is secondary, though a 

 new school of scientists is endeavoring to show that prevent- 

 ing weed growth is even more important than securing proper 

 physical condition. Plowing is the fundamental operation 

 of our present tillage system, and the plow the most effective 

 tillage implement. 



Pulverization changes the hard soil into a deep mellow seed- 

 bed, offering little resistance to the travel of plant roots in 

 search of food and water. It enlarges the feeding area of 

 roots, by placing more plant food and moisture within easy 



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