1^2 ELEMENTS OF AGRICULTURE 



CHAPTER XXIII.— Cultivation of Soils 

 (Continued) 



115. Surface Cultivation of Soils. — Surface cultiva- 

 tion means the pulverizing of the surface soil prepara- 

 tory to planting seed, or else the working of the crop 

 after it has begun to grow. The preparation of the 

 soil for seed planting is usually accomplished by plow- 

 ing. Spading, while it is more efficient than plowing, 

 is too expensive to practice on a large scale, and is 

 resorted to only for gardens. 



116. Plowing. — Some form of plowing is almost the 

 universal method of cultivation, and the plow most 

 generally used in this country is the turn plow; that 

 is, a plow which turns over the first four to six inches 

 of soil. One disadvantage of this form of plow is that 

 it cuts usually to the same depth, and after many 

 plowings the soil over which the bottom of the plow 

 is dragged is apt to become packed, forming what is 

 called a hard-pan. This hardened layer of earth is 

 difficult for the roots of plants to penetrate, and also 

 interferes with the movement of water in the soil. 

 It may be broken up by changing the depth of plowing, 

 which can be most easily effected by the use of the 

 subsoil plow. The subsoil plow follows immediately 

 in the furrow of the ordinary plow, and breaks up and 

 loosens the subsoil. Subsoil plowing is of benefit when 

 the subsoil has a tendency to become hard. , 



