y \ 



136 



O. Uaikiiliara,. 



In every case also an experiment without general manure was made in 

 order to observe principally the effects of the sulphates added on the condi- 

 tion of the soil, since, e.specially with clayey and humus soils, the effects 

 on the soils have to be well distinguished from the effects on the plants. 

 Gypsum, magnesium sulphate and sodium sulphate may be able to liberate 

 potassa from hydrous silicates and render it more available to the plants. 



. With the soil No. I and No. Ill the lime content was larger than the 

 magnesia content and since barley was to be grown the manuring with 

 magnesia might benefit the barley. In these cases the sulphate was 

 applied in the form of crystallized magnesium sulphate. Further for sake of 

 comparison, magnesia was also applied as magnesite with and without 

 sodium sulphate (equivalent to MgSOJ. 



In the case of the soil No. II there was more magnesia present 

 than lime, hence the sulphate applied was CaS04.2H._,0. Control pots 

 contained either limestone or limestone and sodium sulphate. The following 

 table will show the quantities applied per pot : 



Thirty-one seeds p. pot were sown Nov. 29, 1904 and the young plants 

 of about 6 cm. height were reduced to 22, 17 and 21 resp. in the three different 

 soils. The height of plants measured April 8 may be seen in the following 

 table : 



i). The MgO plied as sulphate corresponds to 1/30 of the calculated amount of MgO as 

 magnesite. 



2). These amounts were applied to the second series of soil No. II pot (2), 1/4 of the 

 calculated amount of CaO being applied as CaS04.2HiO (cf. this Bulletin Vol. I, No. i, p. 2S). 



3). This amount was applied to the third series of the soil II. 



