592 Journal of Agricultural Research vol. vi, NO. 16 



The results of water and soil cultures by Gossel (6) failed to substan- 

 tiate the theory of a definite ratio of calcium to magnesium. He obtained 

 the highest yields for beans and barley with water cultures when the 

 ratio of lime to magnesia was 0.04 to i , and concluded that the effect of 

 liming is dependent upon the character of the soil and not upon a definite 

 ratio of lime to magnesia. About this same time the Japanese inves- 

 tigators (22) were actively engaged with the problem. However, their 

 results all seem to bear out the theory of a definite ratio. 



Konovalov (12), a Russian investigator, reports studies with barley, 

 millet, oats, and maize, varying the ratio of calcium oxid to magnesium 

 oxid, as follows: 13.4 to i, 6.7 to i, 3.3 to i, 0.8 to i, and 0.4 to i. He 

 found that the yields tended to increase with the increase of lime appli- 

 cation, provided the magnesia content remained constant. Notwith- 

 standing these results, Voelcker (35, 36, 37) states that the ratio is best 

 at i to i. 



Meyer (20, 21) found that with buckwheat and oats the dependence 

 of maximum yields on a definite ratio of calcium to magnesium could 

 not be proved even in the case of soils containing more calcium than 

 magnesium or vice versa. Undoubtedly the most extensive investiga- 

 tions regarding a definite calcium-magnesium ratio have been con- 

 ducted by Lemmerman (13) et al. They used six different soils and 

 grew vetch, oats, barley, rye, wheat, clover, mustard, and buckwheat, 

 with the investigations extending over three years, 1907 to 1909, inclu- 

 sive. From the standpoint of yields the ratio had no effects within 

 wide limits. Stewart (33) reports soils having 16.88 per cent of calcium 

 oxid and 6.1 per cent of magnesium oxid which were cropped for 40 

 years without the addition of fertilizers, except in the case of sugar 

 beets, which received manure. The 8-year average yields are 80 bushels 

 for oats, 50.4 bushels for wheat, 262.3 bushels for potatoes, and 21.8 

 tons for sugar beets. 



Wartiadi (38) used sand and water cultures with wheat and barley and 

 found that calcium and magnesium were beneficial or detrimental in 

 proportion to their relative amounts in the culture solution. Russell 

 (30, p. 144) finds no connection between the lime-magnesia ratio and 

 the productivity of the soil. Haselhoff (8) also failed to substantiate 

 Loew's theory, while Hopkins (9, pp. 170-171) found magnesium car- 

 bonate beneficial up to 0.8 per cent when added alone and in connection 

 with calcium sulphate in such amounts as to maintain a ratio of 4 to 

 7, respectively, of magnesium oxid and calcium oxid. 



Gile (3) reports that with the chlorids of calcium and magnesium at 

 low concentrations the ratio exerted no influence, while at high con- 

 centrations it was effective. Good yields of pineapples (4) were pro- 

 duced from soils in Porto Rico when the ratio varied between i to 13 

 and 73 to i ; and in one field where the ratio of calcium oxid to magnesium 

 oxid was 1,461 to i a yield of 60 tons of sugar cane was realized. 



