191S.1 FIELD CROPS. 835 



Potato culture, T. B. Hutcheson and T. K. Wolfe (Virginia Sta. Bui. 217 

 {1911), pp. 16, figs. 5). — This bulletin outlines cultural methods for potatoes 

 based upon experimental work and observations made at Blacksl)urg on 

 Hagerstown silt loam soil and deemed applicable to most of the soils west of 

 the Tidewater area. 



In tests of early, medium early, and late varieties of potatoes, the highest 

 average yields for a 5-year period were obtained from Irish Cobbler with 152.06 

 bu. per acre, Early Rose with 170.3G bu., and Vulcan (3-year average) with 

 162.57 bu., respectively. Eye pieces and 0.5, 1, and 2 oz. seed pieces were em- 

 ployed in 3-year tests to determine the influence of size of seed piece on yield 

 with average results of 43.93, 99.75, 148.13, and 172.53 bu. per acre, respec- 

 tively. A comparison of sprouted and unsprouted seed made during 1915 and 

 1916 resulted in yields of 143.13 and 137.5 bu. per acre, respectively. 



Potato fertilizers are briefly discussed, and notes on storage and on potato 

 diseases and insect pests and their control are presented. 



Black heart and the aeration of potatoes in storage, F. C. Stewart and 

 A. J. aiix (Neio York State Sta. Bui. 4S6 (1917), pp. 321-362, pis. 10}.— The ac- 

 cidental discovery that the exclusion of air from potatoes induced the produc- 

 tion of black heart at temperatures much below those employed by Bartholomew 

 (E. S. R., 35, p. 349) led the authors to undertake extensive investigations to 

 determine the relation of the air supply to the occurrence of black heart, and 

 also to determine the effect of storing potatoes in deep piles in cellars and bins 

 and in unventilated pits and piles out-of-doors. Most of the experiments were 

 made with sound washed and dried tubers placed in wide-mouthed glass museum 

 jars having a capacity of 3,500 to 3,700 cc, and provided with tight-fitting ground 

 glass stoppers which were hermetically sealed. To study the effect of storing 

 potatoes in deep piles, tall galvanized iron cylinders 9 in. in diameter and from 

 SO to 126 in. in height were employed. These were left open at the top, but 

 were air-tight at the sides and bottom. One experiment was made out-of-doors 

 with piles of potatoes protected from freezing by a covering of oat straw and 

 soil. The temperatures varied from 2 to 24° C. (35 to 75° F,). The experi- 

 ments were conducted during April and May, 1914; from January to May, 

 1915 ; and from October. 1915, to May, 1916. The Sir "Walter Raleigh was used 

 throughout the investigation. The observations are fully discussed, and form the 

 basis for the following summarized statement of the conclusions reached : 



Potatoes can not long endure close confinement. Within a certain length of 

 time, which varied with the temperature and quantity of air available, tubers 

 confined in hermetically sealed jars became moist over a part or the whole of 

 their surface, and if they were then exposed to the air the moist surface areas 

 turned brown, and the color of the flesh changed first from white to pink and 

 then to black. With a volume of air equal to the volume of the tubers, a con- 

 finement of 10 or 12 days was sufRcient to produce the symptoms described pro- 

 vided the temperature was around 70° P. At a temperature of 55 to 60° 

 about 20 days were required, and at 40° from 23 to 40 days. Tubers in half 

 full and quarter full jars behaved similarly to those in full jars, except that the 

 symptoms were slower in making their appearance. Tubers confined in sealed 

 jars with less than about ten times their volume of air were unable to do more 

 than barely start sprouts. For normal sprouting about 19 volumes of air per 

 volume of tubers were required. Black heart may be expected to appear when- 

 ever the volume of air available to the tubers is less than that required for 

 normal sprouting. 



Different tubers of the same lot exhibited marked differences in suscepti- 

 bility both to black heart and to surface discoloration. The cause of this has not 



