102 CHARLES B. LIPMAN 



sia ratio, indicating that certain balances between the salts in 

 culture media are necessary, and that they may be necessary for 

 widely different purposes and be brought about in widely differ- 

 ent ways. 



Followdng these investigations, Pisciotta'*^ pubHshed results of 

 analyses of sixty Italian soils. He showed that wide variations 

 in the lime-magnesia ratio, due principally to a variation in lime 

 content, obtained in these soils. In only one soil did he find 

 the ratio equal to 1 and he found it less than 1 in four soils. 

 When magnesium sulphate was applied to the soil at the rate of 

 forty pounds per acre, the grain yield was increased if the apph- 

 cation was made at time of seeding, and good net profits fol- 

 lowed. When, however, the magnesium salts were added in the 

 spring, the increase was small, or wanting. The best yields were 

 obtained in soils with a high lime-magnesia ratio, but contrary 

 to Loew's theory, profitable increases were also obtained in soils 

 with a hme-magnesia ratio which was less than unity. 



In making a study of cane soils, Hutin^^ found that cane was 

 capable of accommodating itself to soils which vary in their 

 hme-magnesia ratios so much that there might be from one and 

 one-half to four times as much lime as magnesia in a soil without 

 damage to the cane plant. The work was carried out on the 

 coastal plain sugar cane soil of Peru. At least so far as the nat- 

 ural content of lime and magnesia in soils is concerned, this in- 

 vestigation would not seem to lend any support for the idea of 

 the necessity of a certain ratio between the two materials. 



In studies of a similar nature RusselP^ states that he has never 

 noted cases in English soils which bear out Loew's claim of infer- 

 tility in soils due to excess of magnesia in them. On page 144, 

 of the same work, Russell points out that, in general, the ratios in 

 Enghsh soils fall between 1 and 3 (CaO: MgO), but ratios of 4 

 and 5 are not uncommon, and in ''chalk soils that may rise very 



^^Staz. Sper. Agr. Ital., vol. 46, 1913, no. 10, p. 643. Cited from E. S. R., 

 vol. 30, p. 519, 1914. 



*' Bui. Assoc. Cheni. Sucr. et Distill., vol. 31, 1913, no. 5, p. 347. Cited from 

 E. S. R., vol. 30, p. 326, 1914. 



*^ Soil Conditions and Plant Growth, p. 49, Longmans, Green and Company, 

 1912. 



