THE LIME-MAGNESIA RATIO 101 



lime and magnesia. They could not, however, in these experi- 

 ments, detect any relation which was constant in soil and in 

 plant between the amount of those two compounds in the soil 

 and in the plants and in their effects on growth. To quote them 

 again — ''Bush beans appear to be independent of the lime- 

 magnesia ratio in these soils and also of the increasing amounts 

 of carbonate of lime. . . Since the lime content of plants 



remained constant with increasing amounts of lime in the soil, 

 it does not seem possible that this plant could have adapted it- 

 self to the conditions by precipitation of lime as oxalate." This, 

 therefore, is in contradiction and reply to the claim made by 

 Loew on that point. 



Following these investigations, Meyer, whom we have quoted 

 above, discusses^^ in general the lime and magnesia fertilizer 

 question. Among other statements that author makes the claim, 

 and gives evidence in support of his contention, based on his 

 previous experiments, that the maximum yield of crops is inde- 

 pendent of any fixed lime-magnesia ratio in soils. 



In investigating the question of plant chlorosis in its relations 

 with calcium carbonate. Maze, Rout and Lemoigne'*^ found that 

 corn remains green but that lupines and one species of vetch 

 which was tested, become chlorotic in a medium containing an 

 excess of calcium carbonate. A few drops (0.02%) of ferric ni- 

 trate restored the green color in a few hours. It is concluded 

 from that that iron assimilation is prevented by calcium car- 

 bonate in accordance with the idea presented by Gile, the claim 

 being made that calcium carbonate renders the iron insoluble. 

 They further make the claim that the corn roots secrete malic 

 acid which dissolves calcium carbonate and releases the iron. 

 They believe that leguminous plants do not produce enough of 

 this acid. The interest of this investigation in connection 

 with our subject is that ill effects of an excess of hme may be 

 overcome easily by means other than changing the lime-magne- 



^^ Jahrb. Deut. Landw. Gesell., vol. 27, no. 3, p. 728, 1912. Cited from E. S. 

 R., vol. 28, p. 820, 1913. 



« Compt. Rend. Acad. Sci. Paris, vol. 155, p. 435, 1912. Cited from E. S. R., 

 vol. 28, p. 425, 1913. 



