F °pi d ants seec * mea ^' though naturally one pound of high grade 



blood will furnish practically twice as much nitrogen as 



2 44 one pound of the others. Again, bone tankage, which 

 is quite similar to ground bone in its composition, may 

 be substituted for bone, and vice versa, the substitu- 

 tion depending upon the cost, as the availability of the 

 constituents is not materially different. In the case of 

 potash, the sulphate may be substituted for the muriate 

 without changing the percentage of actual potash in the 

 mixture; whereas if kainit is substituted for the higher 

 grades, four times the weight must be included in order 

 to obtain the same amount of potash, and the amount of 

 the mixture applied per acre must be doubled in order 

 to obtain the same number of pounds of the constituents 

 for a given area. For example, if in a mixture of 



Nitrate of Soda 100 lbs. 



Ground Bone 100 " 



Sulphate of Potash 100 " 



400 pounds of kainit is substituted for the 100 pounds of 

 sulphate of potash, the percentage composition of the 

 mixture would be just one-half the former, as the con- 

 stituents are distributed throughout twice the weight. 



Importance of Mechanical Condition. 



In the next place, care should be exercised in the 

 preparation of mixtures, in order to obtain good me- 

 chanical condition. It is sometimes a difficult matter to 

 obtain a dry mixture from the use of purely mineral 

 fertilizing materials, as superphosphates, and muriate of 

 potash, or kainit — it is apt to become pasty in the drill 

 or planter, whereas, if some dry material, as bone or 

 tankage, is added, the mixture is much improved and 

 the composition not materially affected. 



The Kinds and Amounts to Apply. 



It should also be remembered that the suggestions 

 in reference both to the particular form of the constitu- 

 ents and the amounts to be applied have reference to 

 their application under average conditions of soil and 



