FIELD CROPS. 953 



"Varieties which produced the larger yields gave increased crops the longer the 

 seed tubers .iad been home-grown, while those which produced smaller crops gave 

 decreasing yields the longer the seed had been home-grown." 



The potato crop in the rotations, C. O. Flagg, G. M. Tuckek, 

 and J. A. Tillinghast (Rhode Island Sta. Ept. 1897, pp. 389-393). — 

 Six rotations are in progress in 2 of which potatoes arc planted on 

 clover sod while in the other 4 they are planted after corn. The results 

 for the seasons of 1890 and 1897 are reported. The average results 

 indicate that when potatoes are planted on a clover sod a better yield is 

 obtained than when the crop is planted after corn. "The growth of 

 potatoes upon the clover-sod plats was very rapid and vigorous, indi- 

 cating the presence in the soil of considerable available nitrogen." 



External indication of an increase of solanin in potatoes, 

 SCHNELL (Apoth. Ztg., 13 (1898), p. 775; abs. in Ghem. Ztg.,22(1898), No. 

 95, Repert., p. 291). — In examining potatoes which had caused whole- 

 sale sickness among soldiers, the author found small gray spots which 

 were richer in solanin than the white part of the potato. Whether 

 these gray spots were due to the action of fungi or bacteria he was 

 unable to determine. The potatoes had sprouted vigorously early in 

 June, and contained about 6 times the normal amount of solanin. 



Fertilizer experiments with potatoes, C. O. Flagg, G. M. Tucker, 

 and J. A. Tillinghast (Rhode Island Sta. Ept. 1897, pp. 352-373). — 

 The fertilizer experiments with different amounts of nitrogen, phosphoric 

 acid, and potash for potatoes made in 1896 and 1897 are described and 

 the results tabulated and summarized. The total rainfall for May, June, 

 July, and August is reported as 14.71 in. in 1896 and 19.04 in. in 

 1897. The standard fertilizer used in these experiments as a base upon 

 which comparisons were made consisted of muriate of potash, dissolved 

 phosphate rock, and nitrate of soda. It was applied at the rate of 

 1,678.51 lbs. per acre, and contained 3.2 per cent nitrogen, 8 per cent of 

 available phosphoric acid, and 6.48 per cent of potash. The standard 

 application was the same for both seasons, but the amount of the dif- 

 ferent elements of plant food varied on certain plats, being one-half, 2, 

 and 3 times the amount furnished in the standard fertilizer application. 

 When the amount of an element in the application was increased or 

 decreased the other elements were supplied as in the standard ferti- 

 lizer. The materials used for fertilizers and the amount of the standard 

 applications are given in the following table: 



