THE COMPOSITION AND USE OF FERTILIZERS. 



By L. L. Van Slyke, Ph. D., Chemist, N. Y. Agricultural Experiment 



Station, Geneva, N, Y. 



Part I. — Chemistry of Plants, Plant Foods and Soils. 

 Part II. — Classification and Description of Materials Used 



as Fertilizers. 

 Part III. — Purchase and Use of Fertilizers. 

 Part IV. — Arithmetic of Fertilizers. 

 Part . V. — Average Composition and Value of Fertilizing 



Materials and of Farm Crops. 



INTKODUCTIOK 



The matter in this treatise is to be carefully studied, not merely 

 read, if one expects to obtain the greatest benefit from it. It is 

 suggested that the bulletin be taken up in small portions at a time 

 and be studied constantly, going back to parts previously studied 

 until they are clearly understood. Many may find that Part I 

 especially will need to be studied in this way and it may be well 

 to pass on to the following portions and come back to Part I from 

 time to time. In this way its importance will be more fully real- 

 ized and also its connection with the other parts. The bulletin 

 should be kept at hand for constant reference. 



Until 50 years ago, agriculture was without a scientific work- 

 ing basis. To the investigations of the illustrious German 

 chemist, Justus von Liebig, we largely owe the advances that have 

 been made in agricultural methods during the past half century. 

 The following four laws, which form the foundation of modern 

 agricultural practice, were fully established by Liebig: 



1. " A soil can be termed fertile only when it contains all 

 the materials requisite for the nutrition of plants, in the required 

 quantity, and in the proper for-m." 



2. " With every crop, a portion of these ingredients is 

 removed. A part of this portion is again added from the inex- 



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