FIELD CROPS, 541 



Yields of 3, 4, and 10 tous per acre, respectively, were secured on a field cropped 

 40 years without manure, a well-manured field, and a field that had been in 

 grass for more than 20 years. Sprouted seed yielded an average of 2 tons, 

 3 cwt., and 2 quarters more than unsprouted seed, except in the case of one 

 variety which was attacked by disease. The author reports that in an earlier 

 season when the plants were cut down twice by frost " the sprouted seed gave 

 a very heavy increase amounting in some varieties to 5 tons per acre." Cut 

 seed yielded an average of 1 ton lOJ cwt. more than whole seed and had an 

 advantage of 10.6 in the percentage of small potatoes. Plantings of full and 

 deep crowned seed produced yields showing SO and 60 per cent, respectively, of 

 full crowns, and the author regards the result as showing " that all that can be 

 claimed for selection is that the percentage of objectionable tubers can be kept 

 down but not eliminated altogether." Numerous tables present other results 

 of these investigations, the general purpose of which was to determine the 

 influence of pasture and artificial manures in the renovation and i-estoration 

 of soils. 



Comparative respiration experiments with different varieties of potatoes, 

 J. F. Hoffmann and S. Sokolowskl (Ztschr. Spirit usmdus., 33 (1910), Nos. 33, 

 pp. 391-393, figs. 6; 34, pp. J,01,, 405; 35, pp. 416, 4^, 421; 36, pp. 432, 433; 31, 

 Ijp. 445, 451; 38, pp. 462, 465, 466; nbs. in Momtsh. Landw., 3 (1910), No. 11, 

 pp. 351, 358). — Tables show the protein and nitrogen content of samples of the 

 different varieties of potatoes experimented with, and extensive studies are 

 given of the rate of development of carbon dioxid in each variety at different 

 seasons, temperatures, and relative humidity. 



The authors conclude that water and nitrogen content are not invariable in 

 their influence on the respiration of potatoes as in the case of grains. Potatoes 

 with high water and protein content may be lower in respiration than those 

 low in water and protein. The results may be irregularly influenced by bac- 

 terial activities and resistance due to the character of the skin. Varieties with 

 strong respiration are usually low in keeping quality, but when the reverse is 

 true the result is attributed to the skin. Small potatoes were stronger in 

 respiration than large ones, due to variation in the extent of the surface exposed. 



The respiration of the same tubers varied with the season but it was not 

 clearly established whether physiological or bacteriological conditions deter- 

 mined this variation. The effect of fertilization with saltpeter on the respira- 

 tion and keeping qualities was not constant. There was an evident difl'erence 

 in the effect of temperature on the different varieties but it was so low as to 

 be obscured by bacterial action. Practically no difference appeared in the 

 degree of selfheating of the varieties and experiments on this point are to be 

 repeated under different conditions with 100-kg. samples. The varieties varied 

 among themselves in development of carbon dioxid, content of water and 

 protein, character of skin, and keeping qualities. High water and protein con- 

 tent and rapid development of carbon dioxid usually accompanied low keeping 

 qualities and conversely, but this rule had marked exceptions. The authors 

 regard further experiments in other seasons as desirable for the verification of 

 these results. The use of sterilized tubers is suggested. 



Comparative test of rice varieties, J. E. Van Dee Stok (Teysmamnia, 21 

 (1910), No. 2, pp. 111-111; abs. in Bot. Centbl., 114 (1910), No. 11, p. 441).— 

 The author discusses the results of tests of 24 varieties of rice. Tables state 

 the period required for maturity, yield of straw and paddy, and ratio of straw 

 to paddy for most varieties. The break percentages and percentages of light 

 kernels and of grain obtained from the air-dry paddy of several varieties are 

 also stated. 



