94 CHAPTER VI 



however, flint varieties, although giving smaller yields, furnish 

 silage of better quality. 



The average yield in South Africa is from eight to twelve 

 tons per acre. 



In the Union three methods of ensilaging maize are in 

 vogue — namely, in above-ground (airtight chambers), silos 

 usually built of concrete or stone, pit silos, or by stacking. 



The above-ground silos are much the least wasteful, but 

 the initial cost of erection has limited them from coming into 

 general use. These are generally 20 to 30 feet in height and 

 10 to 15 feet in diameter. The maize is run through a cutter 

 regulated to cut it into lengths of about an inch or so. It is 

 elevated by a blower and delivered into the silo, where a man 

 sees that it is evenly distributed and well compacted, particu- 

 larly the part next to the walls. 



Pit silos are inexpensive in construction and therefore to- 

 day are the most popular. In these the ground, located in a 

 well-drained situation, is excavated, leaving somewhat sloping 

 sides 10 to 12 feet in de])th and of varying capacity. The maize 

 is either put in whole with the stem ends nearest the walls or 

 it may preferably be passed through a cutter. When properly 

 settled, a layer of grass covered with a foot or two of earth is 

 used as a covering. When starting to feed, the pit should be 

 opened from the side and the silage cut vertically. 



Stacking, when done by those competent, is a fairly effi- 

 cient and inexpensive method. Here the whole maize is built 

 with the stem ends outwards into circular stacks 20 to 25 feet 

 in diameter and 12 to 15 feet in height. When built, the whole 

 is covered with straw and weighted down by a layer of heavy 

 stones. The sides are trimmed down to present an even sur- 

 face. 



The underlying principle in all these is the exclusion of 

 air and to have sufficient depth to ensure enough pressure. 



The average weight of a cubic foot of silage is about 40 lbs. , 

 of which approximately one quarter is dry matter. 



It is estimated that the cost of ])roduction of a ton of silage 

 is about 15s. under Transvaal conditions. 



The advantages of ensilaging maize are chiefly : — 



(1) Low cost of production. 



(2) Succulent feed is furnished for any desired season. 



(3) Palatability. 



