WHAT FERTILIZERS TO APPLY 131 



Soil analysis, therefore, is not enough to tell us what 

 fertilizer to use. It is helpful, particularly if it shows the 

 absence of some important element ; but for the average 

 farm it is less instructive than experiments with differ- 

 ent fertilizers. Experiment stations make these experi- 

 ments on the different types of soil in their respective 

 districts. They keep careful records of the kinds and 

 quantities of fertilizers used on different fields, and on 

 sections of the same field, and they measure carefully the 

 crop yield through a period of years before and after this 

 fertilization. Then they publish the results, and suggest 

 allowances to be made for variations in rainfall or in other 

 climatic conditions. 



It is usually safe for the farmer to adopt the advice of 

 a station, based upon such experiments; but it is well for 

 him at least to confirm the experiment himself by keeping 

 records and observing carefully whether the results se- 

 cured by the station are secured also upon his land. 

 And if there are no records of satisfactory government 

 experiments in his neighborhood, or upon his kind of soil, 

 it need not cost the farmer much money or time to experi- 

 ment for himself. Two or three kinds of fertilizer added 

 to as many strips through a field will give a useful basis, 

 at the close even of one season, for comparing the results 

 of the different fertilizers with one another and with the 

 absence of any fertilizer on the rest of the field. The 

 fertilizer that brings the best returns upon a particular 

 soil and for a particular crop is the one to use for that 

 soil and that crop. It is well worth while to find out 

 what this one is. 



PRACTICAL QUESTIONS 



1. Define the four different kinds of fertilizers. 2. Discuss 

 barnyard manure as a direct and indirect fertilizer. 3. What crops 



