CHAPTER XXV 

 FERTILIZER PRACTICE 



THE purchase and use of commercial fertilizers in an 

 economical way requires not only specific technical 

 knowledge of the various materials, as already set forth, 

 but also a certain amount of general knowledge both 

 practical and theoretical. There are at present so many 

 fertilizing materials on the market under various trade 

 names, that the question as to the best one to buy for a 

 certain crop growing under definite soil and climatic 

 conditions becomes a difficult one. The greater the 

 general knowledge, therefore, that a person possesses 

 as to the effects of the different elements on plant growth, 

 as to fertilizer inspection and control, as to methods of 

 buying, as to home mixing, as to methods and time of 

 application, and as to mixtures for special crops, the 

 better he is able to utilize fertilizers that will result in 

 financial gain. That a fertilizer shall be profitable is 

 the ultimate desideratum. Moreover, as all fertilizers 

 exert, either directly on indirectly, a residual effect, the 

 problem necessarily broadens into a study of the systems 

 of applying fertilizers to a series of crops or to a rotation, 

 rather than a study of the effects of one particular ferti- 

 lizer application on one particular crop. 



Note. For discussions of fertilizer practice see Halligan, J. E., 

 Soil Fertility and Fertilizers, Chapters 13-17. Easton, Penn- 

 sylvania. 1912. Also, Van Slyke, L. L. Fertilizers and Crops, 

 Chapters 21-25, and 27-35. New York, 1912. Also, Fraps, 

 G. S. Principles of Agricultural Chemistry, Chapter 16. Eas- 

 ton, Pennsylvania. 1913. 



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