126 CROPS 



salt. Lime, on the other hand, does not improve the taste 

 of the hay. The value of either of these materials as a 

 preservative is very questionable. 



105. Silage. — Inasmuch as haymaking is in large measure 

 a drying process the resulting material is dry, and for general 

 feeding purposes a certain amount of more succulent food 

 is desirable. Silage answers this purpose. It is usually 

 made from corn, but sometimes mixtures of corn and cow- 

 peas, corn and soja beans, oats and vetch are employed. 

 Those crops which do not field cure or dry readily are best 

 employed for silage. Corn is particularly well adapted for 

 this purpose because of its succulence and also because it is 

 an economical crop to use, for the more mature it becomes 

 the better is its composition from a feeding point of view. 

 Hay, on the other hand (Section 104), becomes less digestible, 

 containing less ash, protein, and fat, and more crude fiber. 

 The corn crop not only increases in weight with maturity, 

 but also improves in quality, containing more crude fat 

 and nitrogen-free extract, much less crude fiber, and not 

 very much less ash and crude protein (See Table VI). The 



Table VI. — Changes in the Composition of Corn During 



Growth 



(Pounds in 100 of Dry Matter) 



Date of harvest. 

 Aug. 15, ears beginning to form 

 Aug. 28, a few roasting ears 

 Sept. 4, all roasting ears . 

 Sept. 12, some ears glazing 

 Sept. 21, all ears glazed 



material for silage is cut fine and packed tightly in an air- 

 tight receptacle, called a silo (Figs. 31 and 74). The object 

 is to keep the material away from the air as much as possible. 

 Since it is a moist substance the presence of air will hasten 

 bacterial action and cause putrefaction. 



106. Chemical Changes in Silage Making. — Decomposition 

 occurs to some extent. Some of the sugars, usually dextrose 

 in corn, are fermented by yeasts to alcohol, and the alcohol 

 is changed by acetic bacteria to acetic acid. Lactic bacteria 



