SWEET-POTATO STORAGE STUDIES. 3 



strations and object lessons, with the result that thousands of similar 

 houses are now in use. 



OBJECTS OF THE EXPERIMENTS. 



Many problems arose relative to the management of storage houses 

 built according to the plans as originally made and as modified from 

 time to time. It became apparent that more information was 

 needed on the problems involved. These were — 



(1) The factors which hasten the decay of sweet potatoes in storage. 



(2) The best methods of reducing the losses due to decay and to excessive 

 shrinkage. 



(3) The effects on shrinkage and decay of different methods of handling 

 sweet potatoes. 



(4) A comparison of varieties of sweet potatoes with reference to loss in 

 storage from shrinkage and decay. 



(5) The effects on the keeping quality of sweet potatoes of temperature and 

 humidity in the storage house. 



METHODS OF PROCEDURE. 



Experimental work on sweet-potato storage was begun in 1912 

 and has been continued every year since. During the first four years 

 all the experiments were conducted in houses owned and controlled 

 by farmers or commercial firms, and the management was not en- 

 tirely under the control of the investigators. During the five years 

 1916-17 to 1920-21, inclusive, the work was carried on in a storage 

 house erected for this purpose on the Arlington Experimental Farm 

 at Rosslyn, Va. This house has been under the complete control of 

 the investigators. 



In all of the experiments it was the aim of the investigators to have 

 all the conditions identical, with the exception of the particular one 

 being studied. Where the conditions were not alike the results are 

 not considered in this bulletin. 



In all the experiments conducted in storage houses the sweet 

 potatoes were subjected to a curing process for a period of two or 

 three weeks, the length of time depending upon the weather and 

 the condition of the potatoes. The curing consists of reducing the 

 moisture content of the potatoes by means of artificial heat with 

 thorough ventilation. The temperature during the curing period 

 was usually maintained between 80° and 90° F. by means of 

 limiting apparatus until the potatoes were cured, as evidenced by 

 Hi" "feel" when handled or by the appearance of sprouts. When 

 the potatoes were cured the temperature was gradually lowered to the 

 desired point. The average temperature maintained in (lie different 

 rooms in the experimental house U shown in figure l. 



Ventilation was provided by means of openings in the floor and 

 through the ceiling and roof, as illustrated in figure 2, and by means 



