1919] FIELD CROPS. 31 



The substitution of ammonium sulphate tor potassium nitrate improved the 

 yield in certain proportions, hut caused injury when added In excess. The 



fnliuge, on the whole, showed a greener color than did the plants in the Tot- 

 tinghaui series, which it also exceeded in yield of dry weight of tops at optimum 

 concentrations, though great variations appeared. A close relation was QOted 

 between top yield, root yield, and total transpiration. The water requirement 

 was less in these experiments than in the Tottingham series. 



Growth of wheat (Triticum) and corn (Zea), D. T. MacDougal (Carnegie 

 Inst. Washington Year Hunk, 16 (1917), pp. 85-87). — The facts here discussed 

 as significant were obtained by analyses of the daily course of growth of corn 

 and wheat. 



Retardation of growth of Zea and of Triticum occurred at more than one place 

 in the temperature scale and at different hours of the day. An uneven growth 

 rate was particularly noticeable in Triticum. Temperature may be a cause of 

 arrested growth. The highest growth rate maintained for some time by Zea 

 ranged between 27 and 30° C. (80.6 and 86° F.). No retardations occurred 

 except after 11 a. m. Zea alone showed acceleration late in the day after re- 

 tardation at high temperatures. Wheat probably reaches its upper limit near 

 the temperatures given above. 



The individuality of the bean pod as compared with that of the bean 

 plant, Helene M. Boas (Mem. Torrey Hot. Club, 17 (1918), pp. 207-209).— It is 

 concluded from this study that in case of a variety of string bean the pods 

 exhibited an individuality of almost the same order as that of the plants bear- 

 ing them. It remains to be seen whether the individuality of the pods is due 

 to purely chance differentiation, as in nutrition, or to definite morphological 

 differentiation according to position on the plaat, 



FIELD CROPS. 



[Work with field crops on the TruckeeCarson reclamation project experi- 

 ment farm in 1917], F. B. Headley (U. S. Dept. Agr., Bur. Plant Indus., Work 

 Truckee-Carson Expt. Farm, 1917, pp. 1-12, 13-17, fig. 1).— This reports the con- 

 tinuation of work along the same general lines as previously noted (E. S. R., 39, 

 p. 226), including observations on weather and agricultural conditions on the 

 project, together with a temperature survey of the area. The summer tempera- 

 tures for 1917 are said to have been very favorable for the growth of corn, 

 sorghum, melons, and tomatoes. 



The average yield of alfalfa on the project for 1917 was 3.6 tons per acre, 

 and the average yield on the experiment farm 3.2 tons per acre for an area of 

 8.4 acres. 



In a test with 15 varieties of com, Minnesota No. 13 was first with a yield 

 of 31 bu. of shelled corn per acre. Reid Yellow Dent was first in yield of corn 

 and stover, with 5.05 tons per acre, and Minnesota No. 13 second, with 4.04 tons. 

 Of the corn varieties grown two or more years, Australian White Flint was 

 first with an average yield of 35 bu. per acre. 



In variety tests with barley, Trebi gave the highest yield, 23.6 bu.. followed by 

 a local sort with a yield of 20.5 bu. For the three years 1915 to 1917, inclusive, 

 Coast was highest with 33.3 bu. per acre and the local variety was next with 

 30.3 bu. 



Potatoes planted at weekly intervals from April 19 to May 24. inclusive, gave 

 the highest yield from plantings made May 3. Tests were also made with 14 

 varieties or strains of potatoes, but owing to lack of uniformity in the soil, the 

 actual yields obtained are not deemed of great value. The varieties appearing 



