JOURNAL OF AGBlCETim RESEARCH 



Vol. XV 



Washington, D. C, October 14, 1918 



No. 



CONDITION OF FERTILIZER POTASH RESIDUES IN 

 HAGERSTOWN SILTY LOAM SOIL^ 



By William Frear and E. S. Erb 



Department of Experimental Agricultural Chemistry, 

 The Pennsylvania State College Agricultural Experiment Station 



INTRODUCTION 



It has long been known that when solutions of potassium salts are 

 brought into contact with clayey or loamy soils, the potassium is quite 

 rapidly removed from solution by the soil, with or without leplacement 

 in the solution by other basic elements in chemically equivalent amounts; 

 also, that by immediate washing of the soils thus treated a large part of 

 the potassium they have acquired from the potassium-salt solution can 

 be recovered from the soil. 



It has furthermore been shown by numerous investigations that, when 

 the potassium salt is introduced into a clay or loam soil in a solid, such 

 as the potash salt of a commercial fertilizer, the potassium is quite 

 promptly "fixed," or united with the soil soHds and made stationary at 

 the point of introduction; that the downward movement of the potassium 

 into the subsoil is relatively slight, and that the loss by drainage is 

 small. On the other hand, in a sandy soil the drainage loss may be 

 large (2).^ 



The testimony concerning the usefulness to crops of the potash thus 

 fixed in the soil, the crop increases obtained in many instances by potash 

 fertilization, and also the quantity of potassium taken up by the crop to 

 which the fertilizer has been applied is that, whether a crop increase 

 follows the potassium dressing or not, the crop is, in the majority 

 of cases adequately studied, richer in potassium than the crop grown 

 simultaneously upon the same soil without such fertilization. In gen- 

 eral, the amount of potassium taken up by the crop fertilized with potash 

 as contrasted with that not so fertilized is proportionally much greater 

 than the increase in the total potassium supply of the soil due to the 

 potassium dressing supplied. 



1 Approved for publication, by R. L. Watts, Dean and "Director. Pennsylvania Agricultural Experiment 

 station. 

 * Reference is made by number (italic) to " Literature cited," p. 8i. 



Journal of Agricultural Research. 



Washington, D. C. 



pq 



(59) 



Vol. XV. No. a 

 Oct. 14. 1918 

 Key No. Pa.— « 





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