640 
Vol. XXI, No. 9 
Journal of Agricultural Research 
amount of decay in each crate and the quality of the potatoes which did 
not rot. 
Table I .—Effect of drying sweet potatoes in a current of warm air upon their keeping 
qualities 
TREATED 
Quantity of 
potatoes. 
Time of drying. 
Rate of air 
movement 
in feet per 
minute. 
Air temper¬ 
ature. 
Per¬ 
centage 
decayed 
after 
3 
months. 
Quality of potatoes. 
Pounds. 
°C. 
44 X. 
10 minute . . . 
150 to 200 
46 to 49 
0 
Good. 
41 'A . 
20 minutes . . 
150 to 200 
46 to 49 
0 
Do. 
50 . 
30 minutes . . 
150 to 200 
46 to 49 
0 
Do. 
42 . 
40 minutes . . 
150 to 200 
46 to 49 
0 
Do. 
42K 0 . 
2% hours. 
150 
5 i- 5 
6 99 
None marketable. 
46 . .. .. 
hours. 
150 
5 1 * 5 
46 
Poor; few if any market- 
able. 
43K . 
3K hours. 
150 
5 1 - 5 
63 
Do. 
41 *... 
hours. 
150 
5 i -5 
22 
Poor; less than one-half 
marketable. 
43 b> • 
9 hours. 
190 
46 to 70 
59 
Very poor; none market- 
able. 
41X. 
9 hours. 
170 
46 to 70 
52 
Do. 
40 . 
9 hours. 
174 
46 to 70 
38 
Do. 
42 .. 
9 hours. 
190 
46 to 70 
83 
Do. 
CONTROLS 
40 
42K. 
40X. 
None. 
Same as 
for oth- 
000 
< ers af¬ 
ter treat- 
. ment. 
a Potatoes halved before treatment was started. 
Good; all marketable. 
Do. 
Do. 
b In 15 days. 
Ihese results within the limits of these experiments indicate that any 
attempt at case hardening or of stimulating or hastening the healing of 
the wounds of sweet potatoes at digging time by subjecting them to a 
current of warm air is likely to prove detrimental rather than beneficial. 
The potatoes subjected to a temperature of 46° to 49 0 C. for 40 minutes 
or less were not injured appreciably, neither was their keeping quality 
improved. The control potatoes dug at the same time and handled in 
the same manner, except that they were not subjected to a current of warm 
air, kept equally well. On the other hand, the application of a warm air 
current for more than 40 minutes predisposed the potatoes to decay. It 
is interesting to note also that the potatoes cut in two longitudinally and 
then subjected to a temperature of about 51.5 0 for 2% hours began to 
decay almost at once. Sections of some of these potatoes revealed the 
fact that no differentiation into a starchless layer or the formation of 
wound cork had taken place. 
