LIME REQUIREMENT OF THE SOIL 



105 



on the treated plots. A chemical analysis of the treated soils, more- 

 over, reveals the fact that even after four years one-half of the 

 original dressing of 200 Ibs. of phosphoric acid is still to be found in 

 the first nine inches of soil. Table LIII gives the total and available 

 phosphoric acid found in the soil from the basic slag and untreated 

 plots during the autumn of 1919. By assuming that one acre of soil 

 to the depth of 9 inches weighs 1000 tons, the actual quantity of 

 available phosphoric acid in the two plots has been calculated, and 

 the excess in the basic slag plot taken to represent the amount of 

 the original dressing still left in the soil. 



TABLE LIII. TOTAL AND AVAILABLE PHOSPHORIC ACID IN THE SOIL 

 FROM BASIC SLAG AND UNTREATED PLOTS, IN THE AUTUMN OF 1919 



The above table shows that from a half to three-quarters of the 

 original dressing of 200 Ibs. of phosphoric acid still remains in the 

 soil in an available form, and such results but confirm the conclusion 

 that lack of phosphates can not be the cause of the clover failing at 

 Martin's Hearne and Tysea Hill during the dry season of 1919. 



The application of lime at Tysea Hill and Martin's Hearne at the 

 rate of 35 cwts. per acre of ground lime is more than sufficient to 

 satisfy the lime requirements of these soils, and it would be reasonable 

 to expect that if soil sourness is the only limiting factor to the 



