96 



from a similar amount of raw phosphate 243 })()unds. 

 In this experiment the acid phosphate proved slightly 

 better fertilizer than rock phosphate. Neither fertili- 

 zer, however, gave a marked increase in yield. 



Inoculation 



The soy bean like other le- 

 gumes has the ability to utilize 

 atmospheric nitrogen through 

 the action of bacteria which 

 live on its roots. These bac- 

 teria develop tubercles on the 

 roots of the plants. If there 

 are no tubercles present and 

 the plants are pale green, it 

 is an indication that inocula- 

 tion is lacking or deficient. 



Inoculation Experiments 



In 1902 inoculation experi- 

 ments were made in pots by 

 use of soil from fields where 

 soj?^ beans had not been grown. 

 With seed disinfected in 2 per 

 cent solution of formalin, cer- 

 tain pots were planted June 

 18 without inoculation, and on 

 August 12, 64 per cent of 

 the plants had tubercles. About the same per cent of 

 inocidation was secured from disinfected seed planted 

 in cowpea and peanut soil. With disinfected seed 

 planted in soil fertilized with co\v manure, 100 per 

 cent of the plants showed inoculation. 



In 1903 similar experiments were made, using soil 

 on which no legumes had been grown for six years^ 

 The i)lants bore many nodules. In one set of pots the 

 soil was limed; in another set it was not limed. In 

 those |)()ts limed {hv i)lants bore more tubercles than 

 those planted in ludinud j)ots. 



In later years both disinfected and inoculated seed 

 was ])lanted on land where no soy beans had ever 

 grown. Wherever tubercles were found, they were 

 found on phints fi'oni both disinfected and inoculated 

 seed alike. 



Land that has been well fertilized with barnj'^ard 

 manurc> or is naturally fertile and planted with seed 

 harvested in the ordinary manner will probably need 



Well Inoculated Plant 



