SEVENTEENTH ANNUAL YEAR BOOK— PART VIII 465 



SILAGE AND SILAGE FERMENTATION. 



BY A R. LAMB. 

 Bulletin No. 168, Iowa College of Agriculture. 



Thei-e would be much less spoilage and waste of silage if the more 

 than 22,000 farmers in Iowa who put up this valuable feed understood 

 just what happens in the fermentation process, instead of following di- 

 rections in "cook book" style. There would also be more use of other 

 crops than corn for silage, especially in cases of emergency, if the merits 

 of some of them for this purpose were known. Conditions are not al- 

 ways normal and favorable for the best results in making silage, and a 

 knowledge of the principles upon which the proper preservation of silag§ 

 depends is of considerable value when conditions are unusual. A great 

 deal of uncertainty about silage fermentation still exists. This is evi- 

 denced by the number of samples of moldy silage sent in to the Iowa 

 Agricultural Experiment Station and by the incorrect ideas regarding 

 the fermentation that are still current. 



Investigations and experiments carried on at the Iowa Agricultural 

 Experiment Station during the past six years, as well as at certain 

 other stations, have cleared up a number of doubtful points concerning 

 silage fermentation and disposed of a great deal of the "guess-work" in 

 the discussion of silage problems. Some of the results of that work 

 as to what silage fermentation really is, the causes of the fermentation, 

 and the adaptability of soft corn ears, alfalfa, rape, and other crops 

 to the making of silage, are presented in this bulletin. 



THE FERMENTATION OF SILAGE. 



Certain other well-known fermentative processes are somewhat similar 

 to silage fermentation. When hay is stored too green it is likely to heat, 

 even to the combustion point. This heat is only the outward evidence 

 of other changes which are taking place in the hay. Grain stored in bins 

 undergoes certain chemical changes, which sometimes develop a notice- 

 able amount of heat. These and similar changes, which are undergone 

 by all living plant material when stored in large masses, are in some 

 respects like silage fermentation. The fermentation of sauer kraut is 

 also similar in that the preservation of the kraut depends upon the 

 formation of organic acids by bacterial action. The formation of vinegar 

 from cider involves the production of acetic acid, which is one of the 

 acids found in silage. This change takes place necessarily in the pres- 

 ence of air. On the contrary, the changes which are normal to the for- 

 mation of food silage take place entirely in the absence of air. 



In silage making, the chopped corn forage is tightly packed into an 

 air-tight silo, with plenty of moisture present, and fermentation begins 

 at once. The first evidences of change are a slight rise in temperature 



*Since corn (maize) is the principal silage crop in this country, all 

 references to silage will be understood as being to corn silage unless other- 

 wise stated. 



