AGRICULTURAL CHEMISTRY 



A. E. Vinson, C. N. Catlin 



The work of the Department of Agricultural Chemistry 

 during the year ended June 30, 1921, has been continued along 

 the lines of projects defined in former reports. This work is 

 divided into research, miscellaneous analytical work, and 

 teaching. 



RESEARCH 

 SWELLING COEFFICIENTS OF DRY SOILS WHEN WETTED 

 The method of determining the swelling coefficient of dry 

 soils when wetted, which was originated in this department, wad 

 given further study; first to obtain satisfactory duplicate de- 

 terminations, and second, to compare the swelling coefficient with 

 other physical constants dependent on the texture of the soil. A 

 technical paper covering the details of the method and duplicate 

 determinations will be prepared by the department during the 

 coming year. The following table, however, is given here to 

 show the correlation between the swelling coefficient as deter- 

 mined by our method in the case of a few soils of widely vary- 

 ing texture and the mechanical analysis and moisture equivalent 

 of the same soils. 



TABLE III — COMPARISON 



OF SWELLING 

 CONSTANTS 



COEFFICIENT WITH OTHER 



ALKALI STUDIES 

 Field studies of the treatment of black alkali soil with 

 gypsum have been continued at the University Farm. A good 

 stand of barley was obtained over the most alkaline portion of 



