368 



STATE BOARD OF AGRICULTURfi. 



however, be accidental, the difiference being too small to prove anything. 

 But the soil without dextrose just reaches the greatest rate of uiti'ifi- 

 cation after 27 days, and it would probably within another week have 

 exceeded the nitrate in the dextrose soils. 



The general principle of these two experiments is so interesting and 

 of so much significance especially to soil bacteriology, where we are deal- 

 ing with very diluted solutions, that a test was made to ascertain the 

 substances most concerned in this peculiar behavior of the cultures. The 

 experiment was arranged in the following way: The following eight 

 solutions were prepared, one liter of each: 



Marked O 1% peptone. 



K 1% peptone + 0.1% KCl 



P 1% peptone + 0.1% Na^ HPO« 



Ca 1% peptone + 0.1% Ca Clj. 



KP 1% peptone + 1% KCl + 0.1% Na^ HPO,. 



KCa 1% peptone + 0.1% KCl + 0.1%, CaClj. 



PCa 1% peptone + 0.1%, CaClj, + 0.1% Na^ HPO^. 



KPCa 1%, peptone + 0.1% CaCl^ + 0.1%, Na^HPO, + 0.1% KCl. 



100 cc. portions of these solutions were filled in liter-florence flasks 

 and sterilized in the autoclave. After cooling, 10 grams of a sandy 

 loam were put in each flask, and the amount of ammonia produced was 

 determined in time intervals which seemed most appropriate to give an 

 idea of the progress of ammonification. Much attention was paid to 

 get the final ammonification. All flasks containing the potassium phos- 

 phate, had a sediment, but none of the others. 



AMMONIA PRODUCTION IN PEPTONE SOLUTION WITH MINERALS. 



These absolute results are recorded in another relative way in the 

 following table. In all vertical columns, the ammonia in the solution 

 without minerals is taken as a basis of 100, and the corresponding data 

 of the other cultures are computed according to this base. This en- 

 ables one to read directly the percentage increase or decrease. 



