18 BULLETIN 1063, U. S. DEPARTMENT OF AGRICULTURE. 



shrinkage and 2.19 per cent decay for the storage period of 166f days. 



The results with the Porto Rico variety for two years showed 12.82 



per cent shrinkage, with 0.62 per cent decay for the storage period 



of 158^ days. 



SUMMARY. 



With careful handling it is possible to store and keep sweet pota- 

 toes for four months with losses as low as 7.52 per cent from shrink- 

 age and decay. With ordinary commercial handling these losses ran 

 as high as 20.40 per cent and averaged 10 per cent. (See Table 1.) 



Sweet potatoes stored in houses lost from 0.5 per cent to 2 per cent 

 from decay, while like sorts stored in banks and pits showed a loss 

 of from 4 to 40 per cent. (See Table 2.) 



Sweet potatoes injured in harvesting and handling lost 28.13 per 

 cent by shrinkage, and stock that was carefully handled lost 13.83 

 per cent. (See Table 3.) 



Sweet potatoes sorted from time to time during the storage period 

 showed greater losses from decay than those not sorted. ( See Table 4. ) 



Storage tests with single crates of each of all the important va- 

 rieties of sweet potatoes showed that the shrinkage during the curing 

 period varied from 6.07 to 10.27 per cent. The average loss in weight 

 for all varieties for the storage period was 16.52 per cent, the lowest 

 being 12.96 per cent and the highest 21.01 per cent. (See Table 5.) 



Sweet potatoes stored at 50° to 55° F. lost 13.83 per cent in weight; 

 those stored at 55° to 60° F. lost 15.27 per cent, and those stored at 

 60° to 65° F. lost 15.70 per cent. (See Table 6.) 



In these experiments sweet potatoes of the Nancy Hall, Southern 

 Queen, and Big- Stem Jersey varieties stored in crates showed greater 

 shrinkage than similar stock stored in bins. (See Table 7.) 



The average temperature in bins filled with sweet potatoes is 

 higher than that of the surrounding air. (See figs. 3 and 4.) 



When stored in bins under uniform conditions the Southern Queen 

 variety showed the least decay, the Porto Rico and Nancy Hall were 

 about equal, and the Big-Stem Jersey decayed most of any of these 

 four varieties. In shrinkage the Nancy Hall was lowest, the South- 

 ern Queen next, the Porto Rico next, and the Big-Stem Jersey was 

 highest. (See Table 8.) 



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