ARTIFICIAL DRYIXG OF FORAGE CROPS 15 



drying and scorching are minimized. For good results the forage 

 should be chopped to a fine uniform cut, preferably %-inch machine 

 cut. 



The summary of tests made on the portable dehydrator is shown in 

 table -1, page 16. The capacity of the dehydrator when drying high- 

 moisture forage was approximately 500 pounds of dried forage per 

 hour for the first season. This required the burning of approximately 

 16 gallons of No. 2 fuel oil. Replacement of burner equipment with 

 that of larger capacity and slight modifications of air inlet openings 

 increased the capacity of the machine during the second season. The 

 fuel-burning rate was increased to approximately 20 gallons of Xo. 2 

 fuel oil per hour. The higher burner capacity raised the average 

 inlet temperature of the drum and consequently required very close 

 regulation of the machine adjustment; otherwise scorching of the 

 forage resulted. The automatic controls permitted the temperature 

 inside the drum to fluctuate to an extent that the moisture content 

 of the forage leaving the drum was not uniform. Variations of a few 

 percent in moisture in the loads of chopped forage brought to the de- 

 hydrator required changes of the forage feed rate and outlet tem- 

 perature adjustments. This required considerable manual attention. 



A minimum of three men was required to harvest and dehydrate 

 forage when using this machine. One man was needed to operate 

 the field chopper and haul the forage to the dehydrator, another to 

 feed the chopped forage into the feed conveyor, and the third to sack 

 the dehydrated meal and to operate the dehydrator controls. For 

 long hauling distances, it may be necessary to have a fourth man, so 

 green forage can be kept at the dehydrator at all times. 



Air temperatures at the point where green forage entered the dry- 

 ing-drum were as low as 800° F. and as high as 1.300°, depending 

 upon the drying requirements. The drum outlet temperatures were 

 regulated from 225° when drying forage of low moisture content to 

 300° for forage of high moisture content. Greater moisture contents 

 of the forage required higher outlet temperatures. The forage from 

 the dehydrator for the above tests ranged from 6 to 12 percent (wet 

 basis). 



The dried forage when sacked from the last cooling collector ranged 

 in temperature from 113° to 142° F. 



Forage stored at these high temperatures lost carotene very rapidly 

 until cooled to near atmospheric temperature. Storing sacked dried 

 forage in narrow piles with free circulation of air around two sides 

 of the sacks promoted cooling and resulted in lower carotene loss. 

 Forage stored loose in bins held heat longer than that stored in sacks 

 and lost more carotene. 



USE OF DRIERS 



Capacity 



Alfalfa when cut for hay may contain more than TO percent moisture. 

 When such material is hauled to the drier and dried immediately, as 

 much as 4,133 pounds of water must be evaporated to produce 2,000 

 pounds of hay containing 8 percent moisture (fig. 8). If the hay is 

 left in the swath for several hours its moisture content may be 



