AMMONIHCATION AS AFFECTED. 17 



EXEECISB XI. 



AMMONIFICATION AS AFFECTED BY DIFFERENCES IN THE ME- 

 CHANICAL AND CHEMICAL COMPOSITION OF SOILS. 



1. Weigh oif two 100 gram portions eacli of air-dry sandy, 

 clay, loam and peaty soil, in tumblers. 



2. Add 5 grams of dried blood to each and stir by means 

 of a sterile spatula. 



3. To each add 10 cc. of. a soil infusion prepared by shak- 

 ing 100 grams of a fresh sample of soil in 800 cc. of sterile 

 water for 5 minutes. 



4. Cover and incubate for 7-8 days at 20° C. 



5. Then determine the ammonia formed by transferring 

 and distilling in the usual way. 



