70 



Journal of Agricultural Research 



Vol. XV, No. 2 



amounts of potash dissolved by the former as percentages of the entire 

 amount dissolved by the iV/5 ac'd, and in this comparison taking as 

 typical of the water action the lesults obtained by percolation, because 

 they are internally the most consistent, the percentages thus computed 

 are: 



There appears a very close similarity between these percentages for 

 the two soils. The figures for plot 4 lag somewhat behind those for plot 

 I, but probably no more than should be expected when the slow solution 

 rate here controlling and the much larger amount of soluble potash in 

 plot 4 are considered. In other words, there is here a close parallelism 

 between the solvent effects with regard to potash of the N/^ hydrochloric 

 acid and of the other weak solvents. 



We may infer from these facts of chemical behavior that the residues 

 from potash fertilization remain, at least in considerable measure, in a 

 state of availability in the surface soil to which the fertilizer was applied. 

 The final arbiter of availability is the plant itself. Certain plant evidence 

 in our possession with respect to the availability of the potash in the 

 soils under the treatments here contrasted will be presented later in this 

 paper. 



POTASH OF THE CLAYS AND NONCLAYS OF THE TWO SOILS 



With the purpose of examining the condition of the potash in the two 

 soils from another viewpoint, the clays were separated from the nonclays 

 by the method of sedimentation in distilled water. The details of the 

 process are given in the paragraphs dealing with the water solubility ot 

 the potash. 



The clays and nonclays from each plot were assembled, with slight 

 mechanical losses, on containers and filters, air-dried, and weighed. 



