CHAPTER XVII 



FERTILIZERS 



THE object of fertilizing is to have available 

 in the soil a sufficient quantity of all the 

 elements the plant needs for making a max- 

 imum crop. 



It is also necessary that the soil be in such per- 

 fect mechanical condition that plant food may be 

 made available, and that the roots and rootlets 

 of the plant may be able to easily and readily take 

 up this available plant food. 



Theoretically, in order to determine the amount 

 of fertilizer a crop should require, it would only be 

 necessary to have a chemical analysis and know the 

 tonnage of the crop, and have an analysis to show 

 the amount of fertility in the soil. Practically, 

 these analyses constitute only one of a combination 

 of factors that should be used in estimating what 

 fertilization is necessary. 



The crop indicates whether or not the fertili- 

 zation is right for immediate returns, but the 

 analyses should be a guide to the grower in esti- 

 mating what should be done to maintain large 

 crops continuously. 



A great many formulas for fertilizing have been 

 worked out by growers and experiment stations 

 both in America and Europe. A number of these 

 will be given not that they should be used 

 simply because they have been successful under 



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