EFFECT OF 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. 



(b) 3 and 4, 15 per cent, of moisture. 



(c) 5 and 6, 30 per cent, of moisture. 



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



Note. 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 days. 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. Effect of Moisture on Rate of Ammonification 



