EEFECT OP MOISTURE ON RATE OF AMMONIFICATION 43 



Exercise 9 

 Effect of Moisture on Rate of Ammonification 



1. Weigh into tumblers eight portions, 50 grams each, 

 of air-dry field soil. 



2. Add I per cent, of clover or casein to each tumbler. 



3. Arrange thus: 



{a) I and 2, air dry. 

 (h) 3 and 4, 15 per cent, of moisture, 

 (c) s and 6, 30 per cent, of moisture. 

 {d) 7 and 8, 45 per cent, of moisture. 



iV^/e.— The amount of moisture will depend on the soil type. In this 

 case 45 per cent, represents saturation. 



4. Incubate at 28° C. for seven davs. If casein is used, 

 four days is long enough. 



5. Analyze and compare the results of this test with 

 those of Exercise 6, page 24. Prepare a combination table 

 from the results of these two exercises. 



Table 14. — Efed of Moisture on Rate of Ammonification 



No. 



Moisture 



Ammonia nitrogen in lOO. gm. of soil 



Nitrogen. 



Total. 



Blank 

 subtracted. 



Average. 



ammonified. 



I 



2 



Per cent. 



Air dry. 



do. 



Mgm. 







Mgm. 



Mgm. 



Per cent. 



3 



IS 











4 



15 











5 

 6 



30 

 30 











7 

 8 



45 

 45 











