CHEMICAL CORN-GROWING. 83 



alkaline salt* would be decomposed, and the base would 

 be seized upon and held by the soil as it came into contact 

 with its particles. Thus, if our solution contains sulphate of 

 ammonia and muriate of potash, tlien the soil decomposes 

 these salts, retains within its pores the ammonia and potash, 

 and allows the acids to pass through with the water, in new 

 combinations. Each soil has, however, a certain retaining 

 power, and while one might fix the ammonia or the potassa 

 within a distance of one inch of filtration, another soil, with 

 less affinity towards these bases, might allow the bases to be 

 carried down two inches or more. On account of this pecul- 

 iarity of action, we cannot feel assured that our chemicals 

 are evenly distributed throughout the layers of the soil, and 

 we know that in order to obtain a theoretically perfect crop 

 from a theoretical field, the earth of that field must contain 

 all the elements of fertility in a soluble form, distributed 

 evenly throughout the whole root pasturage. 



If a field be barren, therefore, of all the useful constituents, 

 we might apply to that soil the elements removed by a bushel 

 of corn, with its stover, and yet not receive back our bushel 

 of corn. For the bases being retained by that portion of the 

 soil in contact with them when they came into solution, are 

 not evenly distributed through the land, and there must 

 necessarily be places from which the plant would derive no 

 nutriment ; and we cannot imagine the roots of the plant in 

 contact with every particle of the soil, or coming within reach 

 of all the chemicals ; moreover, the applied salts may have 

 become in part insoluble through chemical actions originating 

 from within the soil. 



To obtain a theoretically perfect crop, the roots of our 

 plant must, at all times during the period of its growth, be in 

 contact with soluble food, and this in the quantity sufiicient 

 for its purpose. If, therefore, a soil should contain enough 

 nitrogen or potassa or phosphoric acid to yield fifty crops of 

 grain, and yet so scattered through the soil that at no time 

 would the roots be in contact with enough soluble matter to 

 satisfy the needs of the plant, then the plant is less flourish- 



* A chemical salt is the material formed by the union of an acid and a base. Thus 

 muriate of potash is a salt, and is formed by the chemical union of muriatic acid and 

 the alkaline base, potassa. 



