90 CHARLES B. LIPMAN 



magnesia in this soil were 1.64% calcium oxide and 1.91% mag- 

 nesium oxide. 



Daikuhara" found in pot experiments with rice instead of bar- 

 ley, that when magnesia is applied as magnesium sulphate in 

 crystaUine form, so little of it is needed in the presence of lime 

 for paddy rice in sand cultures, that the best ratio is 3 : 1 of 

 CaO : MgO, while in the form of natural calcium and magnesium 

 carbonates, the best ratio is 1 : 1, as claimed by Aso. It is further 

 stated that the conclusions thus drawn will hold good for sandy 

 soils while for clay soils the ratios of lime as carbonate to mag- 

 nesia as sulphate are doubled. 



Daikuhara^" also continued his work with the tobacco plant. 

 The plants were here again grown in pots and various ratios of 

 lime to magnesia were tried. A ratio of 4: 1 (CaO: MgO) was 

 found to be the best. In all cases the application of hme bene- 

 fited the tobacco plants. 



Several other Japanese investigators in the following two or 

 three years occupied themselves with the same question and the 

 results of all of their experiments may be said in brief, to be 

 confirmatory in nature of those obtained by Loew, his co-workers, 

 and his pupils, as above described. For example, Suzuki^^ car- 

 ried out a series of pot experiments which emphasized particu- 

 larly the injurious effect of an excess of lime when applied to the 

 soil. He shows among other things that large amounts of lime 

 depress the availability of phosphoric acid for rice, even when 

 phosphoric acid is applied in the very soluble form of secondary 

 sodium phosphate. Calcium carbonate under these conditions, 

 when applied in excess depresses the yields, while, on the other 

 hand, under some conditions, calcium sulphate increased the 

 yields, hence the conclusion above indicated is drawn. When 

 powdered magnesite was applied to the soil, making a ratio of 

 CaO:MgO equivalent to 1:3, the yield was greatly depressed. 



'1 Bui. Imp. Cent. Agr. Ex. Sta. Japan, vol. 1, p. 23. Cited from E. S. R., vol. 

 17, p. 1152, 1905-06. 



12 Bui. Imp. Cent. Agr. Ex. Sta. Japan, vol. 1, p. 17. Cited from E. S. R., 

 vol. 17. p. 1153, 1905-06. 



13 Bui. Col. Agr. Tokyo, Japan, vol. 6, p. 347. 



