272 BOOKS AND CURRENT LITERATURE 



The Utility of Soil Surveys. — In a recent publication of the Uni- 

 versity of California R. L. Pendleton 1 describes the results of an exten- 

 sive laboratory and greenhouse study designed to test the degree of 

 correspondence between the mapping of soils by the United States Soil 

 Survey and the properties of the same soils under controlled conditions. 

 Twenty-four samples were collected, representing four soil types as 

 mapped. The mechanical analysis was obtained both by the Hilgard 

 elutriator and by the method of the Bureau of Soils now accepted as 

 standard. Chemical determinations were made of nitrogen, humus, 

 calcium, magnesium, phosphorus and potassium. Bacteriological work 

 included tests of ammonification, nitrogen fixation, and nitrification. 

 Greenhouse tests were made with a number of common crop plants, but 

 not with all crops on all soils. Although Pendleton refrains from criti- 

 cism of the methods or results of the Bureau of Soils, his data are some- 

 what damaging to the assumption that soils mapped by the Bureau as 

 of the same type are really closely similar. All chemical, bacteriological 

 and crop-culture tests showed wide variations. The mechanical analy- 

 sis, upon which the classification methods of the Bureau of Soils so 

 largely rely, showed that six of the twenty-four collected samples did 

 not belong physically to the soil types which they were supposed to 

 represent. The samples were collected by Pendleton personally. He 

 had had experience in soil mapping under officers of the Bureau of Soils, 

 and was experienced in the methods used. The reviewer has worked 

 with Mr. Pendleton in the field and can testify that his methods and 

 habits of work are exceptionally thorough and careful. The reviewer 

 does not believe that the failure of Pendleton's samples to be what he 

 thought they were can be ascribed to carelessness or unusual personal 

 error. 



The work described was carried out in 1915 and 1916 under the di- 

 rection of Chas. B. Lipman of the University of California. Lipman 

 contributes to the monograph a preface some sentences of which deserve 

 wide publicity and consideration. After explaining that the paper has 

 been seen through the press by him in the absence of Pendleton from 

 the country, Lipman goes on to say: "My own general conclusion from 

 the results obtained by Mr. Pendleton is that they cast grave doubt on 

 the validity of the Bureau of Soils method of soil classification and map- 



1 Pendleton, Robert Larimore. "Are soils mapped under a given type name 

 by the Bureau of Soils method closely similar to one another?" Univ. of Calif. 

 Pubs, in Agr. Sci. 3: 369-498 (1919). " 



