LEGUMES IN GENERAL 251 



tures, by sowing a small quantity of seed with other 

 crops, and by adding to the field a small quantity of soil 

 containing the bacteria. 



The first method is that of securing from the United 

 States Department of Agriculture, the State Experiment 

 Station, or from a commercial firm, pure cultures of the 

 bacteria, which, when put into suitable growing media, 

 multiply very rapidly. The solution containing the bac- 

 teria, after a sufficient number have been produced, may 

 be applied to the seed, which is sown in the usual way, 

 after drying. It may also be used in sprinkling a small 

 quantity of soil, which is then spread over the field and 

 harrowed in. 



The second method has been practiced successfully by 

 many farmers, especially in inoculating for alfalfa. This 

 method consists in sowing a small quantity of seed on the 

 field two or three years before it is seeded to the permanent 

 crop. Sometimes two or three pounds of alfalfa seed are 

 mixed with the red clover seed and sowed with it. A 

 small amount of seed may be sown with the oats in the 

 spring. Some bacteria are carried to the soil with the 

 seed, and here and there over the field there will be a few 

 plants that will become inoculated, and after a time the 

 soil of the entire field will become inoculated. 



251. The third method is more generally employed, 

 and is the one that is usually recommended. This method 

 consists in getting soil from a field that has previously 

 grown the crop successfully and spreading it over the 

 field to be inoculated. Thus the bacteria will be intro- 

 duced with the soil, and they will be present to begin 

 their work on the plant roots as soon as the latter are 

 large enough. In getting the soil from an old field, one 

 should be sure that it contains the desirable bacteria. 



