COTTON 127 



hence, must be furnished if satisfactory yields are 

 to be obtained. 



How to furnish these elements in what forms; 

 at what time; and in what quantity are problems, 

 which, like the poor, we have always with us. 



That fertilizers pay is attested every year on 

 nearly every farm and with most emphatic proofs. 

 That they are often, if not usually, employed 

 without the attention due their importance is also 

 certainly true. 



The judicious use of fertilizers demands that 

 every farmer make not only a study of sources and 

 relative values, but also a study of his own soil and 

 crop conditions. Fertilizers show their greatest 

 profit where the farmer practices thorough prep- 

 paration of land and careful tillage. Here it is, too, 

 that they can be used in greatest quantities with 

 most economical results. 



NITROGEN 



Nitrogen is the most costly element of plant food 

 that we buy, and for this reason its production by 

 means of home-made manures and legumes should 

 be carefully considered. 



Four-fifths of the atmosphere is made of nitro- 

 gen, but unfortunately this atmospheric nitrogen is 

 in a form not available for plant use. There is a 

 compensating influence, however, in the fact that 

 nitrifying bacteria seek out the leguminous crops, 

 and on their roots store up nitrogen in small 

 tubercles, ready for use by the growing plant. 



SOURCES OF NITROGEN 



In commercial forms and factory-mixed ferti- 



