95 



soil of Stackyard Field, and show that the gains already recorded 

 do not depend upon the presence or absence of phosphates and 

 potash, but are the direct result of the applications of lime and 

 chalk respectively. 



1924. 



A return was made in 1924 to Stackyard Field soil, phosphates 

 and potash being used additionally as in 1923. The same amounts 

 of lime and chalk were used as in 1923, and mixed, as then, with 

 the top six inches of soil. An addition of ground limestone, at 

 the rate of 1 ton and 2 tons per acre respectively, was, however, 

 made this year. Wheat was sown on December 18th, 1923. It 

 was noticed that the higher amounts of chalk retarded the 

 germination, but eventually all plants came well. By April the 

 lime pots showed an increasing improvement up to 3 tons per 

 acre, a slight drop occurring with 4 tons. The chalk pots, on the 

 other hand, were not so good, but more level, while limestone showed 

 no increase. 



These appearances were maintained more or less to the end 

 of the growing period, and the crops were cut on August 18th. 

 The recorded comparative results were : — 



Lime and Chalk upon Wheat — Stackyard Field Soil, 1924. 



The results again confirm the preceding ones, and also indi- 

 cate that limestone is ineffectual in the first year. 



4. Magnesia and Magnesium Carbonate on Wheat, 1924. 



As a counterpart of the last-named experiment, a repetition 

 of earlier experiments with magnesia and magnesium carbonate 

 on Stackyard Field soil was made in 1924, phosphates and potash 

 being given also, magnesium limestone also being added to the 

 series. The applications were mixed, as before, with the top six 

 inches of soil, and the respective quantities used were the same as 

 in the lime and chalk experiment (3). Wheat was sown on 

 December 18th, 1923. 



From the beginning, magnesia in the higher amount exer- 

 cised a bad effect upon the young plants, this not being apparent 



