30 EXPERIMENT STATION RECORD. 



day and nol more thau 12 in. apart, varied from 2 to 4 per cent." The 

 maixmum water content was found two or three days after a heavy fall 

 of rain, "which is doubtless caused by seepage of water from a higher 

 level." The miuimum amount of water was about ~> per cent, and this 

 was observed al the end of June. At the end of the season the prairie 

 sod contained G per cent of moisture, the cultivated soil G> per cent, 

 and the subsoiled land S.\ per cent. 



The electrical method of moisture determination in soils, F. D. 

 Gardner (U. S. Dept. Agr., Division of Soils Bui. 12, pp. 24, fig. 1, 

 charts 6).— As a result of field trials of the electrical method of moisture 

 determination in soils described in a previous bulletin, 1 ^ "some slight 

 modifications in the apparatus and in the method of its operation which 

 will greatly facilitate the taking of the observations and the calcula- 

 t ions of the results" are suggested. These include modifications of the 

 electrodes to insure more perfect insulation and to adapt them to " very 

 light sandy soils having a low salt content and small water capacity," 

 the use of lead-covered underground wires for connecting the elec- 

 trodes, and precautions regarding the cleaning of the different parts 

 of the instrument. The standardization of the electrodes by means of 

 direct determinations of moisture in soil is explained, and observations 

 on the effect of the distance between electrodes on the resistance are 

 reported. 



"[] Miring the year] fourteen sets of the instruments were placed in the hands of 

 fanners located in widely different sections of the country and on markedly differ- 

 ent types of soil. Observations were made daily of the electrical resistance of the 

 soil at the depths of 1 to 3, 3 to 6, 9 to 12, and 21 to 24 in., except in a few instances 

 where the 1 to 3 in. depth was omitted on account of the very loose and dry condi- 

 tion of the surface soil. The observations were taken during the crop season of the 

 particular locality and extended over periods of from three to four and one-half 

 mouths, the average time being approximately four months for each observer." 



The results of these observations are reported in charts and tables. 



The bulletin also contains a note by T. II. Means on a modification of 



the electrical method of determining the soluble salt content of soils. 2 



"It has been found that this method is not applicable to soils containing a large 

 amount of soluble salt, as with the alkali soils of the West, for the salt added mate- 

 rially changes the amount of dissociated salt in the soil. This led to a careful 

 review of the work which had previously been done, and it appears probable that 

 the apparent influence of the texture of the soil ... is largely due to the effect of 

 the added salt upon the dissociated salt content of the soil. Correcting for this, the 

 influence of the texture of a soil upon the resistance of a solution seems to be a con- 

 stant which does not vary with the nature of the soil, provided the soil is thoroughly 

 saturated with water. This factor lias not been established with great accuracy as 

 yet, but. it appears to be approximately 0.54 or 0.56." 



The chemical composition of Utah soils, J. A. Widtsoe (Utah 

 Sta. Bui. 52, pp. 37-84). — This is a report of the first of a proposed series 

 of systematic studies of the soils of Utah, and is devoted to the soils of 

 Cache and Sanpete counties. It includes a general discussion of the 



1 U. S. Dept. Agr., Division of Soils Bui 6 (E. S. K,, 9, p. 535). 

 *U. S. Dept. Agr., Division of .Soils Bui. 8 (E. S. R., 9, p. 535). 



