FORAGE AND SOILING CROPS 99 



kind of bacteria are present to form nodules on the roots. 

 Generally no special care has to be taken with clovers and other 

 commonly grown legmnes to see that the proper bacteria are 

 present, but that is not the case with the more recently intro- 

 duced varieties, such as alfalfa and sweet clover, soy beans and 

 vetch. AMien sown for the first time they should always be 

 inoculated with their special nitrogen gathering bacteria. 



The proper bacteria for each legmne is being spread much 

 faster by the fact that there are only seven grouj^s among the 

 cultivated legumes, each group having the same variety of 

 nitrogen gathering bacteria. These groujos are : 



1. Red, Avhite, alsike, and crimson clovers. 



2. Alfalfa, sweet clover, bur clover, yellow trefoil. 



3. Cowpea, Japan clover, peanut, velvet, bean. 



4. Garden pea, field pea, vetches, lentil, sweet pea. 

 V). Soy bean. 



6. Garden or field bean, navy, kidney beans, scarlet runner. 



7. Lupine, serradella. 



Inoculation. — AVhen grown on any soil for the first time, any 

 legume may be inoculated by scattering one hundred to five hun- 

 dred pounds or more of soil to the acre, from an old field where 

 the same legume (or one belonging to the same group as indi- 

 cated above), has been previously grown successfully and 

 produced nodules. 



If soil is difficult to secure, a small amount may be obtained 

 and thoroughly sifted and well mixed with the seed after they 

 have been made sticky by being moistened with a small quantity 

 of water containing a little liquid glue or molasses and alloAvod 

 partly to dry. A quart or two of soil to each bushel of seed will 

 be sufficient. When treated in this way each seed will have a thin 

 coat of soil,'' 



All things considered, probably the most satisfactory method 

 of inoculation is to use cultures. These may be obtained from 

 nearly all seed houses. The seeds are simply moistened some 

 time before planting wdth the liquid. Complete directions come 

 with the culture. Under certain restrictions, limited quantities 

 are supiolied by the United States Department of Agriculture 

 and by several experiment stations. 



If the soil is rich in nitrogen, legumes will grow well without 

 inoculation, but in that case no part of nitrogen used by them 

 will be taken from the air, and one of the principal advantages 

 of gro^^^ng them will be lost. 



MVisconsin Circular 9fi; Bullclin 202, Illinois Experiment Station. 



