1918] Lipman-GerieTce : CaCO s and CaS0 4 and Soil Solution 27."> 



This idea has, however, been confused with the zeolitie hypothesis 

 from which, in some respects, it is quite distinct. Due to both concepts, 

 the teaching is still largely in vogue that CaCO :1 and CaS0 4 possess 

 as one function in soils a power to set potash and other bases free from 

 their insoluble combinations. In spite of the general acceptance of 

 this view, however, some practical agronomists have called it in ques- 

 tion and it seems necessary to determine if the hypothesis and the 

 laboratory experiments used in support thereof are valid. Briggs and 

 Breazeale 7 have recently made an attempt to answer definitely the 

 question as to whether or not lime or gypsum applied In soils docs 

 affect the potassium content of the soil solution produced by ortho- 

 clase, pegmatite, or orthoclase-bearing soils in contact with water. 

 They checked their results by growing young wheat seedlings in the 

 solutions produced by the treatment of the mineral or soil with lime 

 or gypsum and water. As a result of these experiments, they con- 

 clude that the "availability to plants of the potash in soils derived 

 from orthoclase-bearing rocks is not increased by the addition of lime 

 or gypsum. In some instances, a marked depression of the solubility 

 of the potash in the presence of gypsum was observed." While the 

 authors specifically refer to "soils derived from orthoclase-bearing 

 rocks," the statement carries the implication, owing to the stated 

 object of their investigation, that the potash-bearing silicates of any 

 kind in soil are not likely to be affected in solubility by the addition 

 to the soil of lime or of gypsum. The fact that this conception is con- 

 trary to what one would expect from theoretical considerations regard- 

 ing soil-solution reactions, appeared to render it desirable to investigate 

 the subject farther. We therefore planned and executed the following 

 experiment : 



Calcium carbonate or calcium sulphate were each added to soils, and 

 throughly mixed with them in the different cases as further indicated 

 in the tables. The soils thus mixed were placed in pots in the green- 

 house. Water was added to make optimum moisture conditions and 

 such moisture conditions were maintained for a period of nine months. 

 Three soils were used, viz: Oakley blow sand, Berkeley clay adobe, and 

 a greenhouse soil, the latter having been originally made by admixing 



s Prescott, J. A., The reaction between dilute acid solvents and soil phos- 

 phates, Proc. Chem. Soc, vol. 30, p. 137, 1914. 



a Wiegner, Georg., Zum Basenaustausch in der Ackererde, Jour. Landw., vol. 

 60, pp. 110 and 197, 1912. 



7 Briggs, L. J., and Breazeale, J. F., Availability of potash in certain ortlm 

 clase-bearing soils as affected by lime and gypsum, Jour. Agr. Kes., vol. 8, p. 21, 

 1917. 



