Steam Sterilization ox Water-Soluble Matter in Soils. 253 



Table II. — Showing Disappearance of Soluble Matter and Stationary 



Condition of Nitrates in Steamed Soil 



The large disappearance of the soluble matter is very striking. This is 

 doubtless due, in part at least, to chemical and physical absorption. 

 Within something over a month there was a decrease of nearly seventy- 

 five per cent in the soluble matter. The nitrates during this period 

 remained practically stationary. Unless inoculation with nitrifying 

 bacteria did not take place, which does not appear likely, some con- 

 ditions were unfavorable to their development, and the large amount of 

 organic matter in solution may account for the repressed nitrification. 



Table III represents the results of more extended analyses made 

 immediately after sterilization, and 39 days later in the case of one soil, 

 and 34 days later in the case of the other two. 



Table III. — Showing Changes Taking Place in Steamed Soils on Standing. 



Treatment 



Freshly steamed . . . 

 39 days after steam- 



ing 



Freshly steamed . . . 

 34 days after steam- 



inf? 



Freshly steamed . . . 

 34 days after steam- 



inK 



Field 

 No. 



332 



346 

 322 



337 

 322 



337 



Substances in aqueous extract, p. p. m. dry soil 



Soil 

 No. 



ToUl 

 solids 



2590 



1716 

 3407 



1981 

 276s 



2058 



Inor- 

 ganic 

 matter 



522 



336 

 324 



198 



46s 



270 



% In- 

 or- 

 ganic 

 matter 



in 

 soluble 

 matter 



I9S 

 9-5 



10 .0 

 16.8 



131 



Nitro- 

 gen 

 inor- 

 ganic 

 matter 

 and 

 am- 

 monia 



96 



S6 

 127 



61 

 98 



77 



Ni- 

 trates 



31-3 



74.4 

 3-1 



S-7 

 3-1 



Ni- 

 trites 



9.8 

 trace 



Am- 

 monia 

 nitro- 

 gen 



36 



4-7 

 46 



17 

 38 



23 



Am- 

 monia 

 nitro- 

 gen in 

 dilute 



HCl. 



ex- 

 tract 

 p.p.m. 



dry 



soil 



40 



47 

 S6 



47 

 42 



41 



Am- 

 monia 

 nitro- 

 gen 

 soluble 



in 

 water 



90 



TO 

 82 



36 

 90 



S6 



As in the case of the soils in Table II there is on standing a decrease 

 in the quantity of soluble matter. The soluble organic and inorganic 

 matter decrease in about the same ratio. There is a notable decrease 



