172 MAGNKSIA IMPRKGNATKl) SOILS. 



applied in large quantities to plots and where lands have been 

 injured hy the application of too large quantities of magnesia 

 lime, i)eat will be a pioper and efficient remedy." 



The deleterious influence of ma<>nesian lime on crop i)ro- 

 du(dion was reported by the XTnited States Commissioner for 

 Agiicultuie in 18T(), and Adolf Mayer* in 188(> mentions unpio- 

 ductiveness as characteiistic of soils lich in magnesia. Loew,t 

 in 1901, in a review of the ratio between lime and magnesia in 

 soils of different countries states: " It will be seen from this 

 review (1) that the ratio of lime to magnesia ranges between 

 wide limits; (2) that in the majority of cases lime predominates 

 over magnesia ; (3) that in all the instances c-f great fertility the 

 soil never shows any marked excess of magnesia over lime, but, 

 on the contrary, more lime than magnesia." 



He Avrites also : " Lime and magnesia can exert their indis- 

 pensable nutritive functions only in certain dependence upon 

 each other. Hence a certain ratio between these two nutrients 

 will produce the most favourable results." 



May, J in 1901, published results of some cidture experi- 

 ments ^^ ith oats, wheat, cowpeas and tobacco in water, sand 

 and soil cultures, and drew the following general conclusions : — 



" Magnesia in a soil in great exces.^ over lime in a finely 

 divided or soluble condition is noxious to the growth of 

 plants.'" 



Daikuharaj^ in 1905 observed that on well-manured soils 

 in which the ratio of calcium to magnesium was 0'34 to 1, the 

 yield of naked barley was doubled by jjroducing a ratio of 1 to 1. 



Bernardini and Siniscalchi|| in 1908, as a result of growing- 

 lupins in pot cultures, made the observation that " the injuri- 

 ous action of an excess of lime and the poisonous action of an 

 excess of magnesia in a soil is not due to the absolute quantity 

 of calcium and magnesium ions absorbed by the plant, but to 

 the ratio in wdiicli they are absorbed." 



Konovalov'sH results, published in 1907, with wheat, 

 lupins and oats grown in water and sand culture, do not confirm 

 Loew's view that " there is a definite lime magnesia ratio for 

 each plant." According to Konovalov, the yield is increased 

 Avith the increase of the proportion of lime to magnesia. 



* Mayer: " Lehrbuch der Agrikulturchemie," 3rd ed., 2, 111. 



t Loew : "Liming of soils from a ]:>liysiological standpoint." 

 U.S.A. Agric. Dept., Veg., Physiol, and Path. Div., Bnl. 18, 1-60. 



+ May: " Experimental study of the relation of lime and magnesia 

 to plant growth." U.S.A. Agric. Dept.. Plant Indus. Bur., Bui. 1, 

 37-54. 



§ Daikuhara : "Correction of a very unfavourable ratio of lime 

 to magnesia in a soil for the culture of liarlev." Japan Imp. Cent. 

 Agric. Expt. Stn., Bui. 1, 13-16. 



II Bernardini and Siniscalchi : " Intorno all influenza di vari 

 rapporti fra calce e magnesia sullo sviluppo delle piante." R. Senola 

 Sup. Agr. Portici. 



^Konovalov: "On tlie question of the different correlations 

 between lime and magnesia in the nutritive solution." Russ. Journ. 

 Expt. Landw. 8; 257-280. 



