162 THE CULTURE OF FARM CROPS. 



ingly effective for the purpose of breaking up the ground. 

 But for the improvement of the land and for increasing its 

 fertility one plowing alone is quite insufficient. The soil 

 should be broken up and pulverized thoroughly all over 

 the field, and the sub-surface over which the horses have 

 trodden and which the sole of the plow has rubbed and 

 hardened and made solid and impermeable, should be 

 broken up and opened to the admission of water and air. 

 Several plowings should be given. A wheat crop should 

 never be put in without at least two plowings and the land 

 for a corn crop should be thoroughly well and deeply 

 plowed in the fall. Plowing at this season for a spring 

 crop is a most effective way of improving the land. The 

 land roughly throw r n up in ridges is left with as much sur- 

 face as possible exposed to the frost, that the soil may be 

 pulverized and made fine and mellow. A winters expo- 

 sure in this way will liberate much mineral plant food by 

 disintegrating the soil and bringing it in larger part into a 

 soluble condition. The newer soil brought up by the fall 

 plowing is thus brought under the free action of the atmos- 

 phere, and aided by the effects of the frost, this develops 

 the plant food in it and makes it available for the crops. A 

 consideration of the principles discussed in previous chap- 

 ters which relate to the relation of the atmosphere, w r ater, 

 and heat and cold, to the soil ; with a knowledge of the 

 precise purposes for which the plow is intended ; will en- 

 able any thoughtful farmer to work out the requisite 

 methods for improving his land by plowing, for himself. 



Subsoil plowing, has been a bugbear to many farmers be- 

 cause the practice of it has been mistaken. It is commonly 

 supposed that this term, means the use of one plow behind 

 another in the same furrow, for the purpose of turning up 

 8 or 10 inches more soil on the top of the first turned over. 

 This is not intended and would result in a permanent injury 

 to the land. All that the subsoil-plow should do, is to fol- 

 low the first plow and break up the sub-surface and the 

 hard crust left by previous surface plowings. This hard 

 crust seals the lower soil against the entrance of air and 



