728 EXPERIMENT STATION EECOKD. 



ure of the degree of homogeneity of the soil of an experimental field, and pro- 

 poses as a scientific criterion the coefficient of correlation between neighboring 

 plats of the field. An exceedingly simple formula for the calculation of such 

 coefficients has been deduced. 



" Let S indicate a summation for all the ultimate or combination plats of the 

 field under consideration, as may be indicated by the capital Cp or lower case p. 

 Then in our present notation, v\'hich is as much simplified as possible for the 

 special purposes of this discussion, 



{[S(Cp')-S(p^)]lm[n(n-l)]}-p-^ 

 rpiP2= ^2 



where P is the average yield of the ultimate plats and ap their variability, and 

 n is constant throughout the m combination plats." The method of application 

 of this coefficient is illustrated by the use of published records of several 

 investigators, involving experiments with mangolds, wheat, and timothy hay. 



" The remarkable thing about the results of these tests is that in every case 

 the coefficient of correlation has the positive sign and that in some instances 

 it is of even more than a medium value. In short, in every one of these experi- 

 mental series the irregularities of the substratum have been sufficient to influ- 

 ence, and often profoundly, the experimental results." 



It is noted that nothing could " emphasize more emphatically the need of a 

 scientific criterion for substratum homogeneity than the facts that correlations 

 between the yields of adjacent plats ranging from r=0.115 to r=0.609 can be 

 deduced from the data of fields which have passed the trained eyes of agri- 

 cultural experimentei's as satisfactorily uniform." 



[Field crops] work of the Truckee-Carson reclamation project experiment 

 farm in 1914, F. B. Headley (U. S. Dept. Agr., Bur. Plant Indus., Work 

 Tuckee-Carson Expt. Farm, 1914, PP- 1-9). — This reports the progress of work 

 at the experiment farm near Fallon, Nev. (E. S. R., 31, p. 828), and near-by 

 farms. Weather records are given and data as to agricultural conditions, 

 which include acreage, yields, and farm values of the main money-producing 

 crops in 1914 and a comparison of the data with those of 1912 and 1913. 



Yields in variety tests with 11 varieties of alfalfa ranged from 72 to 134 lbs. 

 per 100-ft. row , with four varieties of fodder corn, from 13.53 to 19.85 tons per 

 acre of green weight ; with six varieties of wheat, from 16.3 to 31.8 bu. per acre ; 

 with six varieties of oats, from 16.6 to 24.5 bu. per acre; with 24 varieties of 

 corn, from 554 to 1,390 lbs. per acre; and with 22 varieties of potatoes, from 

 4 to 61 lbs. of marketable tubers per 100-ft. row. 



[Field crops work at tlie Canadian stations and farms in 1913], J. H. 

 Geisdale et al. {Canada Expt. Farms Rpts. 1914, PP- 3, 4, 15-19, 22-24, 28, 29, 

 88-40, 41, 42, 45, 48, 52, 53, 55, 56, 58, 59, 60, 63, 64, 67, 68, 12, 13, 11, 18, 80, 

 81, 83, 104-109, 119-123, I4I-I8O, 183-291, 510, 511, 557-559, 560, 563-566, 515, 

 516, 580-582, 587, 588, 608-613, 643-646, 670, 683, 684, 686, 695, 698, 118, 119, 

 125, 126, 143, 152-828, 881-940, 941-950, 995-1022, pis. iS).— This reports the 

 continuation of work previously noted (E. S. R., 32, p. 431) and is a detailed 

 account of the work already mentioned (E. S. R., 30, p. 829; 32, pp. 530, 532), 

 with meteorological data and additional data on variety and manurial tests 

 with potatoes, tobacco, and sugar beets. 



Experiments with spring grain in 1914, P. R. Fedoeov (Besenchuk. Selsk. 

 KTioz. Opytn. Stantsiia, No. 58 {1914), PP- ^3). — In a 4-field rotation system the 

 crops preceding wheat were peas, corn, sunflowers, millet, potatoes, carrots, and 

 wheat. The greatest yields were after potatoes and carrots, the smallest after 

 wheat and sunflowers. 



