264 



Bulletin 275. 



Table VIll 



Fig. 73 — Effect of adding an infusion of unsterilized soil to a sterilized soil as indi- 

 cated by a crop of wheat ten weeks after planting 



Pot J2 — Soil No. 5 untreated 

 Pot j6 — Soil No. 5 sterilized 

 Pot j4 — Soil No. 5 sterilized and treated with 



an infusion of the same soil not sterilized 



Although the germination was poor in every case, which would lessen 

 the value of the results, there can be little doubt that the effect of the 

 infusion was to increase the rapidity and amount of germination. 



On March 29th the best growth was in the unsteamed soil, the next 

 best in the steamed soil to which the infusion was added, and the 

 poorest in the steamed soil. 



The wheat was harvested on May 3, before it had begun to head. 

 This period of about six weeks constitutes approximately the time re- 

 quired for soil of this kind to recover sufficiently from the effects of steam- 

 ing to give about the same growth of wheat as does the same soil un- 

 steamed. The yield of crop was as follows: 



