Farmyard manure acts m promotmg ,,„ ,- 



1 -^11 1 11 I ^ • ° Why Farm- plants 



plant erowth almost wholly because it con- , „ . 



^ . ° , , -^ yard Manure 



tarns these three substances; green manur- , ^,, 99 



, , , ^ , ' » , and Other 



mg IS valuable tor the same reason and t» j i. 



Products are 



largely for that only. Various refuse sub- y , , . 



stances, such as bone, wood ashes, etc., 



contain one or more of these plant food elements, and are 



valuable to the farmer and planter on that account. A 



number of crude chemicals contain Ammonia, or Potash, 



or Phosphoric Acid, or some two of these, or even all 



three of the plant food elements, and are valuable to 



agriculture accordingly. In fact, in whatever form, state 



or condition this plant food occurs, crops seem to be able 



to make a more or less ready use of it. However, the 



manufacturer, the farmer and the planter ... ^, 



must not overlook the fact that all three ,,, 



r 1 1 1 1 TVT Elements 



or these elements are needed. JNo excess t j- i-i 



r r 1 Indispensable. 



of any one, nor ot any two, can make up 



for the deficiency of any one. To illustrate, should a 

 soil be given enough Phosphoric Acid and Potash for a 

 crop of 8o bushels of corn per acre, but only enough Nitrate 

 Ammonia for 40 bushels, the yield cannot go above 40 

 bushels. The chain is no stronger than its weakest link. 



The Quality of Manures and Fertilizers. 



While plant food is always plant food, Nitrate a \ 



like all other things it possesses the limita- p j- ♦ ^ ^ 



tion of quality. Quality in plant food means Arnmon^atV 

 the readiness with which plants can make 

 use of it. In a large sense, this is dependent upon the 

 solubility of the material containing the plant food — not 

 merely solubility in water, but solubility in soil waters as 

 well. Fertilizer substances freely soluble in water are 

 generally of the highest quality, yet there are differences 

 even in this. For example, Nitrate of Soda is freely soluble 

 in soil liquids and water, and is the highest grade of plant food 

 ammoniate; sulphate of ammonia is also soluble in water, 

 but of distinctly lower quality because plants always use 

 ammonia in the Nitrated form (the form in which it occurs 

 in Nitrate of Soda), and the ammonia in sulphate of am- 

 monia must be Nitrated before plants can make use of it. 



