1918] Lipman-GericJce : CaCOj, and CaS0 4 and Soil Solution 281 



not to be dependent, in any large degree, upon the significance of any 

 isolated portion of our data. The table which we hold to be most 

 significant is table 3 and the two chief conclusions which we desire to 

 draw from our work are (1). that a soil may be distinctly affected, as 

 regards the solubility of its constituents through its treatment with 

 ( !a( !0 3 or with CaS0 4 ; and (2), that this is not necessarily so. however, 

 and may hold for one soil and one constituent in one case, and not in 

 another, depending on the nature of the physical-chemical systems 

 dealt with and upon the composition of the soil mineral complexes. In 

 these two conclusions from our experiment, one can find a reconciliation 

 of the two diametrically opposed views with regard to the effects of 

 CaC0 3 and CaS0 4 on soils and we offer our discussion as a contribu- 

 tion to such a reconciliation. 



Summary 



From experiments to determine how CaC0 3 and CaS0 4 affect the 

 water soluble iron, calcium, magnesium, potassium, sulphur, and phos- 

 phorus in soils as determined by ordinary water extractions, the fol- 

 lowing outstanding conclusions were drawn : 



1. All soils do not behave alike when treated with CaC0 3 or with 

 CaS0 4 . They should not be expected to do so, considering their 

 mineral composition, the law of chemical equilibrium, and the nature 

 of colloid action in soils. With this conception as a basis, the con- 

 flicting statements in our literature on the effect of CaC0 3 and CaS0 4 

 on the soluble potassium supply in soils may easily be accounted for 

 and each view may be regarded as correct under certain circumstances. 



2. Potassium was found to be rendered more soluble by CaC0 3 and 

 by CaS0 4 applications in clay adobe soil and in a greenhouse soil made 

 therefrom, but not in a blow sand soil. 



3. The soluble calcium content was increased in all soils studied 

 by ( 1 aC0 3 or CaS0 4 applications. This does not prove that the same 

 will hold true for all other soils. 



4. The soluble magnesium content of all soils studied was increased 

 by CaC0 3 treatment. It seems to have remained unaffected or even 

 to have been depressed by CaS0 4 treatment in all but one case in each, 

 the Oakley and the greenhouse soil with the small gypsum application. 



5. The soluble iron content was probably increased in the solution 

 of the greenhouse soil by the treatment in question. It seems also to 



