276 TJniversitii of CaJifornid TuhJicatlons in A(/ricuI(ura1 Sciences [Vol.1 



class has been that of rendering innocuous, in part or in 

 whole, the alkali salts without their removal from the soil. In 

 the latter a division may again be made into methods of chemical 

 treatment, such as that against sodium carbonate, or "black 

 alkali," with gypsum and its transformation into the less harm- 

 ful Glauber salt or sodiiun sulphate, and methods of heavy irri- 

 gation and deep tillage for the purpose of disseminating the 

 salts through a larger internal soil surface, thus rendering less 

 concentrated the soil solution of alkali salts. It may be added 

 in this e(mnection that empirical methods of alkali soil treat- 

 ment, such as those of Symmonds^ and Darnell-Smith- in ap- 

 plying nitric and sulphuric acids respectively, and those of 

 others employing barnyard manure, have in a few instances 

 been rewarded with good results. Fuller details with reference 

 to these experiments need not be given here, since they will be 

 discussed in the more complete report which will appear when 

 our experiments have matured. 



Basis op the Present Experiments 

 It will l)e noted above that ameliorative measures in alkali 

 land treatment have been, with the exception of that of the 

 drainage treatment and that of the Hilgard proposal of gypsum 

 treatment against black alkali, of an empirical nature and not 

 based on established scientific principles. Some measures have 

 indeed been employed without any good reason. It occurred 

 to the writers, therefore, to attack the problem of alkali treatment 

 in soils on the scientific basis of principles established on theore- 

 tical or experimental grounds. The latter included, broadly 

 speaking, the principle of antagonism between ions," and those 

 of the behavior of soil colloids and chemical soil constituents in 

 the presence of soluble salts, or on the removal of soluble salts.* 



1 Journ. Agr. Gov. New South Wales, vol. 21 (1910), p. 257. 



2 Eept. Govt. Bur. Microbiol. New South Wales, vol. 2, p. 209. 



' See papers of Osterhout in University of California Publications in 

 Botany and those of G. B. Lipman in Centralblatt fiir Bakteriologie, 2"" 

 Abt.; also paper soon to appear by C. B. Lipman and W. F. Gericke, in 

 Journal of Agricultural Eesearch. 



* In detailed studies carried out by L. T. Sharp, which are soon to be 

 published, many data of a fundamental nature have been obtained, on the 

 im])ortance of the relationship existing between soil colloids and soluble 

 salts, particularly when the latter are leached from a soil. 



