June, 1920] SOIL SCIENCE 43H 



by the freezing-point method. Where the cropped soils had given evidence of decreased 

 productivity the rate of formation of soluble material was higher in the virgin than in the 

 cropped soil samples. — William J. Robbing. 



SOIL CLASSIFICATION 



2949. Pendleton, R. L. Are soils mapped under a given type name by the Bureau of 

 Soils method closely similar to one another? I'niv. of California Publ. Agric. Sci. 3: 369-408. 

 PI. 43-74. 33 text fig. 1919. — -An inquiry into the physical, chemical, and biological char- 

 acters of samples of certain soils supposed to belong to the same types. The principal studies 

 were made upon llanford fine sandy loam and San Joaquin sandy loam. Random samples 

 were not procured, instead, bulk samples were taken from one locality in each area. — The 

 mechanical analyses and moisture equivalent values for the several types showed differences 

 of sufficient magnitude to justify the field separation, but the hygroscopic coefficients were 

 not so distinctly correlated with soil types. — The nitrogen, phosphorus, and calcium content 

 of the types was quite distinct; while the magnesium and potassium content was not well 

 marked. — The ammonifying power of the samples was more closely correlated with type 

 than the nitrogen fixing or nitrifying powers. — Samples of soil used for cultures under glass 

 gave varying results. While different representatives of a given type did not give similar 

 yields of plants, yet "the types are distinct with respect to their fertility, considering their 

 average production." — "It is pointed out that despite its defects, the work of the Bureau of 

 Soils is of value, and is practically the only type of soil classification and mapping possible 

 under the conditions imposed." — A prefatory note by C. B. Lipman gives certain criticisms 

 on the methods and validity of soil classification. — H. S. Reed. 



MOISTURE RELATIONS 



2950. Anonymous. [Rev. of: Alway, F. A., and G. R. McDole. Relation of movement 

 of water in a soil to its hygroscopicity and initial moistness. Jour. Agric. Res. 10:391-428. 

 1917.] Jour. Ecol. 7:98. 1919. — The authors conducted experiments on the capillary rise 

 of water and the downward penetration of various amounts of water having their initial 

 moisture always above the hygroscopic coefficient. The relative rates and heights of rise 

 in different soils are not similar to the relative rates and distances of penetration, nor was 

 there a definite dependence of the rise upon hygroscopicity. An abundance of data upon 



these and similar phenomena of water movement are presented. — Geo. D. Fuller. 



2951. Anonymous. [Rev. of: Stewart, Guy R. Effect of season and crop growth in 

 modifying the soil extract. Jour. Agric. Res. 12: 311-368. 1918.] Jour. Ecol. 7: 93. 1919 — 

 The author, in presenting a historical review of the subject, draws attention to the contra- 

 dictory nature of many of the results. Experimental data extending over 2 years with 13 

 soils, cropped and uncropped, showed not only striking differences between the soluble 

 nutrients of the different soils but also notable differences between the nitrates, calcium, 

 potassium and magnesium in the cropped and uncropped soils of the same sort. Phosphates 

 did not exhibit corresponding differences. In general the investigations show that large 

 amounts of water-soluble nutrients are developed by cultivation, fallowing and biennial 

 cropping. — Geo. D. Fuller. 



2952. Howard, Albert, and G. C. Howard. Drainage and crop production in India. 

 Agric. Jour. India 14:377-387. 2 pi., 2 fig. 1919. — A general discussion of drainage and 

 effect on soil fertility in India. Illustrations show the effect of soil aeration on root devel- 

 opment. — J. J. Skinner. 



2953. Hibbard, P. L. Changes in composition of the soil and of the water extract of the 

 soil, following addition of manure. Soil Sci. 7:259-272. 1919. — Fresh manure when mixed 

 with soil increases the carbon dioxide in the soil, decreases the total carbon, does not affect 

 the total nitrogen, first decreases and then increases the total water-soluble material. — William 

 J. Robbins. 



