BUREAU OP SOILS. 211 



SOIL CHEMISTRY. 



Early in the year the soil laboratories were reorganized and the soil 

 chemical investigations were placed in charge of Dr. E. C. Shorey. 



This division, while necessarily organized to carry on work of a rou- 

 tine nature for other divisions of the bureau and other bureaus of the 

 department, is carrying on important investigational work along sev- 

 eral lines. 



The most important of these is the study of the inorganic compo- 

 sition of soils. This includes not only complete analysis of important 

 soil types carried on in close cooperation with the Soil Survey, but 

 also special studies to determine, if possible, the forms in which the 

 various soil constituents are present in soils. To accomplish this, the 

 problem has been attacked along several new lines and along old lines 

 on a scale not heretofore attempted. Equipment has been provided 

 and methods have been studied for the investigation of water extracts 

 of soil made from soil in lots of 1 ton and interesting results already 

 have been obtained. 



A phase of this work completed in the past was the determination 

 of the quantities of the rarer elements in soils; as a corollary to this 

 the study of the ash of plants grown on such soils was taken up. This 

 study of ash composition was made with special reference to the pres- 

 ence or absence of the rare elements that had been found in soils. 

 This work has been completed during the year, and the results will 

 be available for publication in a short time. 



Another important investigation on which progress has been made 

 during the year is the liming of soils. Greatly increased interest in 

 the use of lime in agriculture has been shown during the year, stimu- 

 lated, no doubt, by the fertilizer situation, and the investigation has 

 been undertaken with the aim of making the use of lime in agriculture 

 more intelligent. Progress in this work has been made along two 

 lines. The form in which lime is present in a large number of soil 

 types has been determined, and the results are being prepared for pub- 

 lication. This information is necessary to a proper understanding of 

 the results obtained in the second part of the investigation, viz, a 

 study of the chemical reactions that take place when lime is added 

 to a soil. Some interesting results already have been obtained, but 

 this phase of the work is yet in the initial stage. 



SOIL PHYSICS. 



In the physical laboratory investigations have been continued on 

 excessive sou erosion, the moisture relation of the soil with a special 

 study of the critical moisture content, the pressure exerted by soils 

 under changing moisture conditions, the character and movement of 

 the soil atmosphere with particular attention to the absorbed gases of 

 the soil, and the separation and examination for distinguishing fea- 

 tures of the very fine material in heavy clay soils. 



In addition to these lines of research, mechanical analyses have 

 been made for the soil survey of the principal soils surveyed during 

 the year and for other bureaus in this and other departments. One 

 man has been continuously occupied in the designing and constructing 

 of special apparatus for use in the laboratories of the bureau. Work 

 has been begun on a detailed study of some of the more important 

 physical properties of the principal soil types. 



