SOILS. 21 



largely from the sand or gravel, are essential to furnish an 

 adequate coating for corn stalks, straw and the valuable 

 glasses. As they are exhausted they must be again supplied 

 or the crops will fail. Besides yielding an important food to the 

 crop, lime is essential to produce decomposition in the mass 

 of vegetable matter, as well as to combine with and aid in 

 furnishing to the growing plants, such of their food as the 

 atmosphere contains. Ashes are one of the best applications, 

 as they possess the silicates, lime, potash, and other inorganic 

 materials of plants in great abundance, and in a form readily 

 adapted to vegetable nutrition. Gypsum is also a valuable 

 manure for peaty soils. 



SUBSOILS AND THEIR MANAGEMENT. 



The efficiency of soils for producing good crops, depends 

 much on the subsoil. If this consists of impervious clay or 

 hard-pan, so as to oppose a ready escape to the water, it is 

 evident the accumulation of the heavy rains, will materially 

 injure the vegetation above them ; for it is certain that while 

 nothing is more essential to productive crops than an adequate 

 supply of moisture to the roots, nothing is more injurious than 

 their immersion in stagnant water. When such is the char- 

 acter of the subsoil, it should be under-drained if possible, 

 or if this be not practicable, it should be broken up and 

 loosened by the use of the subsoil plow. 



A variety of plows have been constructed for this purpose, 

 but unless it be intended to deepen the soil by an admixture 

 of manures, care should be taken to avoid bringing up the 

 subsoil to mix with that on the surface. In addition to the 

 more ready escape of water thus secured by breaking it up, 

 the air is also admitted, which enables the roots to strike 

 deeper, and draw their nourishment from a much greater 

 depth. The increased distance through which the roots 

 penetrate, furnishes them with additional moisture during 

 a season of drought, thereby securing a luxuriant crop when 

 it might otherwise be destroyed. This is frequently a great 

 item in the profit of the farmer; as besides the increase of 

 crop which follows a dry hot season when a full supply of 

 moistuie is furnished, the product is usually of better quality; 

 and the general deficiency of agricultural produce which 

 ensues from seasons of drought, makes his own more valuable. 



As a result of this practice, there is also a gradual increase 

 in the depth of the soil, as the fine and more soluble parti- 

 cles of the richer materials above are constantly working 



