LIME REQUIREMENT OF THE SOIL 



101 



through the courtesy of Professor Gilchrist, and the lime require- 

 ment of the soil determined with the results given in Table LII. 



The acidity of the soil on Plot 4 is quite appreciably greater than 

 on the untreated plot in spite of the fact that it has received, during 

 the twenty-four years the experiment has been in progress, a total 

 dressing of about two tons of basic slag to the acre. The botanical 

 analyses of the hay from Plot 4 show moreover that it is not possible 

 to maintain a permanent bottom of clover on this plot, and were it 

 not for the comparison with Plot 8, it might reasonably be assumed 

 that the sourness of the soil was responsible for the partial failure 

 of the clover plant. Plot 8, however, has received a dressing of lime 



TABLE LII. LIME REQUIREMENT OF SOIL SAMPLES FOR PLOTS 4, 6 

 AND 8 AT TREE FIELD, COCKLE PARK 



Soil Samples taken 1919 



every three years since 1897, and since 1905 each application has 

 been at the rate of 1 ton per acre, the plot receiving in the form of 

 basic slag the same amount of phosphate as has been applied to 

 Plot 4. In all five tons of lime have been applied to the plot, more 

 than four times the amount required to satisfy the lime requirement 

 of Plot 4. There is now a small reserve of calcium carbonate in the 

 soil on Plot 8, but in spite of this fact the soil has still a small 'lime 

 requirement' and neither the crop nor the herbage are any better 

 than on Plot 4. 



It seems fair to conclude from this evidence that the continued 

 application of heavy dressings of basic slag over intervals of three 

 years does not suffice to supply the lime requirement of heavy clay 

 soils under grass. On the contrary the results indicate that such 

 soils are liable to become even more sour than similar soil left 

 untreated. 



