52 ELEMENTARY AGRICULTURE 



they do not seem to thrive without the legumes and the 

 legumes do not thrive without the germs. Sometimes 

 clover refuses to grow on certain soils. The reason may 

 be that there are no germs in the soil. Such soils should 

 be "inoculated," i. e.. the germs should be planted 

 there, and then the clover will grow. These germs are 

 sent out by the United States Department of Agricul- 

 ture in little cakes, somewhat resembling yeast cakes, 

 which may be dissolved in water and sprayed on the 

 land, or the seed inoculated with this solution. 



Triplicate test of bacteria in growing alfalfa in ordinary soil 

 without fertilizers. Jars marked "BAC" contain alfalfa bacteria. 



UNIVERSITY OF ILLINOIS. 



Clover Restores Nitrogen to the Soil. In order to 

 restore nitrogen to worn-out soil it is only necessary 

 to seed with clover or some other legume. The germs 

 found in the tubercles on the roots of the legume will 

 feed upon the nitrogen of the air and store it up in the 



