Fertilizers for Cereals and Grasses 219 



of less importance in the past than the other elements, and 

 it frequently does not need to be included in the fertilizer, 

 while phosphoric acid is always needed. 



The results of field experiments on this plan in New Jer- 

 sey, on reasonably good, loamy soils, indicate that phos- 

 phoric acid and potash are of much more importance in 

 fertilizers for corn than nitrogen, whereas upon sandy 

 soils, nitrogen and potash are of relatively more impor- 

 tance than phosphoric acid; that is, even where "exten- 

 sive" practice is used there are conditions where one or 

 more of the elements are not required in order to secure 

 maximum crops, which eliminates the necessity for an 

 immediate outlay for those constituents that are not 

 lacking. Where experiments of this sort have not been 

 carried out and the specific needs determined, it becomes 

 necessary to assume that all of the constituents are 

 required, and to apply the amounts and proportions of 

 those which the general considerations of the soil, season, 

 climate and crop would seem to demand. 



As already pointed out, the methods of fertilization 

 here suggested, though in many instances apparently 

 positive, are not to be interpreted as absolute rules, but 

 rather used as guides, based upon the best information 

 that it has been possible to obtain, both as a result of 

 scientific inquiry and of practical experience. 



THE IMPORTANCE OF SYSTEM IN THE USE OF FERTILIZERS 



The following rotation is assumed, in order to show 

 the necessity of a definite system of work, which is quite 

 as important in this branch of farming as in many others 

 in which system is apparently more essential, though 

 in fact it is quite as necessary to observe a definite system 



