15 



is only a waste of time and material to apply the culture to potatoes, oats, 

 wheat, etc. As plainly stated on each bottle, the cultures are carefully 

 prepared for one species of plant, and if used for other species failure of 

 the experiment may be expected. Plain directions for the use of the 

 culture accompany each bottle, and these directions must be implicitly 

 followed if good results are to be expected. 



When Inoculation is of Benefit. 



If a crop is thriving- it indicates that either the soil is plentifully 

 inocuated with the bacteria necessary to produce nodules on that par- 

 ticuar species, or else that the soil already contains an abundant supply 

 of nitrogen upon which the plants can live. In either case the use of 

 artificial cultures would be of little if any benefit. On the other hand, if 

 the crop fails to thrive and upon "examination no nodules are found on 

 the roots, it is an indication that the culture should be used. Sometimes 

 the use of the culture proves beneficial to the crop when a few nodules are 

 present. Of course, failure to thrive may be due to other causes than 

 lack of nitrogen. The soil may lack available potash or phosphoric acid, 

 or may be deficient in lime. Inoculation does not and cannot remedy this. 



When it is intended to sow seed of a legume which never has been 

 grown upon the soil, inoculation of the seed should prove beneficial. This 

 is true even if other legumes have been grown on the same soil, as the 

 bacteria forming root nodules on one species do not necessarily form 

 nodules on the roots of other species. 



If soil once becomes thoroughly inoculated as indicated by a success- 

 ful crop and the presence of numerous nodules, the use of artificial inocu- 

 lation with later seedings is considered unnecessary if a three-year to 

 five-year rotation is followed. 



It should be definitely understood that the use of artificial inoculation 

 with bacterial cultures will in no way compensate for carelessness in 

 selection of seed, preparation of the soil, or subsequent care of the crop. 



Advantages of Seed Inoculation. 



There are certain advantages over other methods to be gained in the 

 inoculation of seed. Soil may be transplanted from a field which has 

 successfully grown legumes, and used as a top dressing on the field to be 

 sown, but the method, especially if the soil is brought from a distance, is 

 cumbersome and expensive. Furthermore, noxious weed seeds may be 

 carried in such soil, and gain a foothold in sections not previously infested. 



When inoculation of the seed is practised, the bacteria remain in 

 intimate association with each seed, and the chances of early root infec- 

 tion and consequent nitrogen assimilation are enhanced. The cultures 

 distributed from this laboratory are for seed inoculation. 



The cultures are sent in glass bottles securely packed in a mailing 

 case, each one accompanied by a sheet of directions for its use. (Fig. 3.) 



A copy of these directions follows : 



