REPORT OF THE DEPARTMENT OF 
BACTERIOLOGY. 
INOCULATION AS A FACTOR IN GROWING 
ALFALFA.* 
H. A. HARDING AND J. K. WILSON. 
SUMMARY. 
1. This bulletin records the need of inoculation and means for 
supplying this need as determined in 67 fields distributed among 33 
counties of this State. 
2. The bacteria, Ps. radicicola, which enable alfalfa to obtain 
nitrogen from the air were present, at least in small numbers, in 
practically all of the 67 experimental fields. 
3. They were present in sufficient numbers to produce an inocula- 
tion in any considerable number of the young alfalfa plants in only 
one-third of these fields. 
4. An attempt to supply the germs by applying pure cultures of 
Ps. radicicola to the seed, drying and sowing, resulted in almost 
complete failure. 
5. Applying soil from an old alfalfa field at the rate of 150 to 
300 pounds per acre invariably produced an abundant inoculation 
on these experimental fields. 
6. While but 15 of the 67 experimental plats produced a success- 
ful crop without inoculation, 48 adjacent plats where inoculating 
soil had been applied produced successful crops. Accordingly 
alfalfa growing, on 33 of the 67 fields which were tested, was 
changed from a failure to a success by the application of inoculat- 
ing soil. 
*A"reprint of}Bulletin No. 300. 
