Steam Sterilization on Water-Soluble Matter in Soils. 259 " 



matter is the striking feature of this solution and it is probably the 

 cause of the lessened crop production. 



The diluted extract of the steamed soil produced a larger crop than 

 the diluted extract of the unsteamed soil, although the transpiration 

 was less. By referring to Fig. 71 it will be seen that the root growth 

 is greatly shortened where the plants were grown in the undiluted 



STKR 



e 



UN -ST Ell 



Fig. 70 — \\ heat seedlings grown in cxUact^i oj slcunird diul niislc<niicil soils 



I'lauls on left "Slcr."groivn in extract of steamed soil 



I 'hints on right ''I'nster." grown in extract of tmstcamed soil 



