[lynde] lime requirements OF SOIL 23 



Then Ci+c = OC 

 or c = OC — Ci 

 1 1 I 



r OR ri 

 ri X OR 



If this calculated resistance, r, is greater than the original resist- 

 ance, rs, of the Ca (HC03)2 solution, it would seem that CaCOa has 

 been absorbed by the soil and that the soil is acid. 



If the calculated resistance, r, is less than the resistance, r2, it 

 would seem that something has been dissolved from the soil and since 

 there is an excess of COo in the solution it would seem likely that the 

 substance dissolved is a carbonate and that the soil is alkaline. 



(5) The Ratio. If we divide the calculated resistance, r, by the 

 resistance, r2, we obtain a ratio which should give us a meas- 

 ure of the alkalinity or acidity of the soil. 



Results 



Of the twelve soils used in the work, eight were taken from 

 different fields of Macdonald College farm, namely, D 1, D 2, D 3, 

 D4, Ml, M2, M3, M 4. They are all clay loams and have been 

 manured in the regular rotation but have not been limed. They 

 were found to be alkaline or slightly acid. 



The remaining four soils were received from the experimental 

 farm at Charlottetown, P.E.I. Previous to 1915 they had received 

 neither manure nor fertilizer, but in 1915 they were fertilized at the 

 following rates: 



Plot Application 



48 15 tons manure 



49 , 7}/^ tons manure +175 lbs. mixed fertilizer 



50 (check) No manure, no fertilizer. 



52 15 tons manure +175 lbs. mixed fertilizer. 



The mixed fertilizer contained: 



75 lbs. sodium nitrate. 



1603^2 lbs. acid phosphate. 



1603^ « 7% Basic Slag. 



1123/^ " 40% Potassium chloride. 



These soils are light sandy loams with a high iron content. They 

 were found to be decidedly acid. 



