Legume and Grass Silage 13 



stored in the same silo with corn silage, either above or below. There is 

 apparently no need to fill continuously. Surface spoilage will usually not 

 start for two or more days. Spoilage, however, may be serious when sev- 

 eral lots are put in at widely spaced intervals without sealing. 



Sealing the Silo 



When the silage was not to be fed within a few days after filling, surface 

 spoilage was materially reduced in many cases by sealing the silo with a 

 foot or more of wet sawdust, weeds, straw or other waste materials. A 

 layer of tar paper between the silage and the sealing material reduced 

 spoilage to practically nothing in several instances. A number of operators 

 held surface spoilage to a few inches without special sealing, by leveling 

 and tramping the top very thoroughly and then sprinkling the surface for a 

 few hours with water. 



Adding Phosphoric Acid as a Preservative 



Thirty- four operators among the total of 380 who took part in the 

 survey used commercial phosphoric acid as the preservative. Two of these 

 operators decided that in the future they would change to the molasses 

 method. All the others appeared to be satisfied. 



Commercial phosphoric acid is not corrosive in the sense that other acids 

 are corrosive. It will not injure the person or the clothing and is easy to use. 

 It cannot, however, be handled in steel drums because it attacks metal to 

 some extent, but does not injure the silage cutter or blower as it passes 

 through it. The machine, however, should be washed ofif after use. Phos- 

 phoric acid has not yet been distributed successfully in wooden barrels. 

 These difficulties add to the cost of handling and therefore the final cost. 



Method of Use 



Phosphoric acid may be used with all legume and grass crops that are 

 suitable for the same type of silage as preserved with molasses. The action, 

 however, is direct in bringing about the desired acidity of the silage. The 

 fermentation is less and therefore less heat is produced. Consequently from 

 a theoretical point of view, less energy and therefore food value, is lost by 

 this method of preservation. 



The field operations are the same as for molasses silage in getting the 

 crop to the cutter and have been fully discussed. 



Amount of Acid to Use 



To prevent bacterial action, the maximum amount of acid necessary to 

 preserve legume crops, as represented by alfalfa or soybeans, seems to 

 be 16 pounds (1^ gallons) to one ton of green material. No one of 



