l86 THE FORAGE AND FIBER CROPS IN AMERICA 



209. Inoculation. For soils only moderately well adapted to 

 the growth of alfalfa, three conditions have seemed desirable 

 if not essential to success: (i) the application of an abundance 

 of manure; (2) the application of lime; and (3) the artificial 

 introduction of bacteria accustomed to growing in alfalfa root- 

 tubercles. This inoculation can be successfully accomplished 

 by putting the living organisms upon the seed immediately be- 

 fore seeding, or by sowing upon the soil just before seeding 

 from 100 to 400 or more pounds, of soil from an alfalfa 

 field where the tubercles are abundant. (139) The latter 

 method has been more largely practised and has been found 

 in a large percentage of cases to improve the stand, and during 

 the first season at least, result in a large number of root- 

 tubercles of a more vigorous growth. Generally in such cases 

 few, if any, root-tubercles occur during the first season on the 

 uninoculated soil, while they are abundant on the inoculated 

 soil, the relative vigor of growth depending on the abundance 

 of inoculation and on the fertility, presumably especially on 

 the abundance of soluble nitrogen in the soil. The more 

 abundant the root-tubercles the greater the difference in 

 growth; the more abundant the soluble nitrogen the less the 

 difference in growth. Generally in these trials the uninoculated 

 fields or plats make such poor growth that they are plowed up 

 at the end of the first year, hence there are few observations 

 on the relative yields obtained the second season from the in- 

 oculated and uninoculated areas. Results at the Cornell Station 

 indicate an increased yield of hay from the inoculated areas. 1 

 The Alabama Station first called attention to the increased vigor 

 of alfalfa through inoculation by incorporating in the soil dust 

 from bur clover soil. The increase in hay attributable to in- 

 oculation was 336 per cent. 8 



iNew York Cornell Sta. Bui. No. 237 (1906), p. 156. 

 2 Alabama Sta. Bui. No. 87 (1897), p. 477. 



