r^^. B. Hutchinson and K. MacLbnnan 



101 



in set («) was allowed to remain untreated, that in set (b) was treated 

 with 10 c.c. of toluene per bottle, while that in set (c) received the same 

 quantity of toluene and 2-0 per cent of calcium carbonate. After two 

 days the toluened soils were spread out on sterilised paper in order to 

 allow the antiseptic to evaporate and then returned to the bottles. 

 The analytical data are given in Table X. 



Table X. The Effect of Calcium Carbonate on Ammonification. 



With the cessation of nitrate production the effect of calcium car- 

 bonate on ammonia formation becomes evident after 32 days, but 

 this becomes still more pronounced by the end of the second period of 

 the experiment, the gains during this time with the untreated soil, 

 toluened soil and toluened soU ■w'ith carbonate being 3, 6, and 22 parts 

 of nitrogen respectively. It is evident therefore that ammonification is 

 subject to retardation in this soil. 



Table XI. The Effect of Calcium Ca,rbonnte on Nitrification. 



The second experiment consisted in the determination of the nitrates 

 produced on the addition of ammonium sulphate to the soil, the various 

 sets comprising (a) soil alone, (&) soil with 0-10 per cent, ammonium salt, 

 and {c) soil with a similar amount of ammonium salt and 2-0 per cent. 



