104 



CHARLES B. LIPMAN 



tion of Miege and Compain/^ bearing on the subject of magne- 

 sia in soils. They carried out field experiments with dolomite 

 on plots about six-tenths of an acre in size. The dolomite had 

 a Ume-magnesia ratio of 1:5. The soil used was a clay loam 

 containing 0.86% hme in the surface with no magnesia, and 

 with 0.35% of each lime and magnesia in the subsoil. The ap- 

 pHcations of dolomite depressed the yields, while appHcations 

 of lime increased the yields on these plots. This indicates that 

 in the surface soil in which the application of dolomite should 

 have been instrumental in making much better hme-magnesia 

 ratios, since no magnesia was present at all to begin with, it 

 really made conditions worse by making the ratio approach the 

 one claimed by Loew to be ideal, and that an apphcation of lime, 

 which should have had the opposite effect because it increased 

 that material in the total absence of magnesia, had the contrary 

 effect of increasing the yields. 



BeHeving at one time that the theory of Loew might account 

 for the chlorotic conditions of citrus trees in certain parts of Cali- 

 fornia in which large quantities of marl were found in the sub- 

 soil and sometimes also in the surface soil, Hilgard and Lough- 

 ridge proceeded to inaugurate a series of investigations along two 

 different lines, one of them aiming to overcome the bad effects 

 of a high hme ratio as compared to magnesia by applying mag- 

 nesium sulphate in large quantities, and the other by making a 

 study of the hme-magnesia ratio in the soils on which chlorosis 

 commonly occurred in that region. These investigations have 

 never been published, but the writer of this review has referred 

 to some of the results obtained, in an article^^ written some time 

 ago. These results, in brief, have shown that magnesium sul- 

 phate apphed in very large quantities and at different times, 

 could not cure the chlorotic condition in the citrus trees in ques- 

 tion. When on the other hand, the ratios of hme to magnesia 

 in the soils were studied, it was found that good vigorous trees, 

 showing no signs of chlorosis were found on soils with ratios of 



" La Vie. Agr. et Rur., vol. 3, no. 19, p. 532. Cited from the Monthly Bui. of 

 Agr. Intel, and International Inst, of Agr. at Rome. 

 " Pacific Rural Press, vol. 81, no. 24, p. 272. 



