592 



Journal of Agricultural Research 



Vol. XII, No. 9 



Table I. — Acid formation in stover silage 



Age. 



Week 



3/7 



1 



2 



3 



4 



5 



6 



8 



10 



12 



Total 

 solids." 



Per cent. 

 28.9 



35- 5 



26. 7 

 26.8 



27. I 

 29.7 

 31.2 



27-5 

 32. I 

 25.8 



Acid in total solids. 



Nonvola- 

 tile.^ 



Per cent. 



Trace 

 o. 16 



•95 

 1.36 



1-54 

 1-51 

 2. 00 



2-53 

 2. 64 



3-15 



Volatile, c 



Per cent. 

 0.51 

 87 

 36 

 41 

 49 

 55 

 69 

 92 

 82 

 24 



Ratio of 

 nonvolatile 

 to volatile. 



5- 40 



1-43 

 I. 04 



•97 

 I. 02 



•85 



•7S 

 •75 

 •71 



u Air-dried. 



b Calculated as lactic acid. 



c Calculated as acetic acid. 



It is seen from the figures in Table I that for the first week the vola- 

 tile acidity was greatly in excess if the nonvolatile portion ; that from the 

 second to the fifth week the two were apparently present in about equal 

 amounts; and that from the sixth week on, the nonvolatile acids were in 

 excess, the proportion of nonvolatile acidity increasing to the end of the 

 experiment. The total acidity obtained was somewhat lower than is 

 usually found in ordinary silage. This is probably to be expected, in 

 view of the chemical differences in the raw materials. In this con- 

 nection, however, it should be noted that in this experiment samples 

 were not taken after the twelfth week. It is not unlikely that the acidity 

 increased some after the last sample was secured. In regard to the pro- 

 portion of nonvolatile to volatile acids, if we accept the ratio i to 0.75 

 reported by Dox and Neidig (5)^ as representing a general average for 

 ordinary silage, it will be seen that our results on com stover silage in- 

 dicate a remarkable agreement in this respect between these two types of 

 ensilage. 



Fermentation temperatures. — Temperature records were obtained 

 by means of four resistance bulbs with about 60 feet of insulated cable 

 attached to each which w^ere buried in the silage as the silo was filled. 

 The bulbs were located as follows : 



No. I. About 2 feet from the bottom and in the center of the silo. 

 No. 2. About 6 feet from the bottom and about 3 feet from the center of the silo. 

 No. 3. At the same height as No. 2 but about 3 feet from the center in the opposite 

 direction. 



No. 4. About 12 feet from the bottom and in the center of the silo. 



The ends of the cables were located at a convenient place on the out- 

 side of the silo so as to allow easy attachment for temperature readings. 

 Table II gives the temperatures obtained from April 4, the day the silo 

 was filled, until June 16. 



• Reference is made by number (italic) to "Literature cited," p. 6co. 



