METHODS OF SOIL MANAGEMENT 



143 



since both depth and frequency of plowing bear directly on the cost of 

 the operation. Mold-board and disk plows are used for this purpose. 

 Either of these implements turn the soil, pulverize it and cover rubbish. 

 The implement to be preferred is determined largely by the character of 

 the soil and its condition. Disk plows work best in rather dry soil. Mold- 

 board plows are much more extensively used and will work under a wider 

 range of soil conditions. The form of the mold-board plow varies con- 

 siderably, and different forms are applicable to different purposes and 

 different soils. The sod plow has the minimum curvature and inverts 



4 ' 



i 



1 Miilte^ 



A Deep Tilling Double-Disk Plow. 1 



the furrow slice with the least pulverization of the soil. The stubble or 

 breaking plow has much more curvature of the mold board, and gives 

 more thorough pulverization of the soil. The greater the curvature of 

 the mold board and the more thorough the pulverization of the soil as a 

 result of it, the heavier will be the draft. Sharpness of the share and 

 smoothness of the plow surface tend toward lightness of draft. The 

 presence of roots and stones may somewhat increase the draft of plows. 

 The texture, structure and physical condition of the soil, especially with 

 reference to its water content, greatly influence draft. The soil plows 



1 Courtesy of The Spalding Tilling Machine Company, Cleveland, Ohio. 



