36 Journal of Agricultural Research voixx.No. 1 



Roux (39, p. 147) grew some 20 species of calcifugous plants in cal- 

 careous soils. All species made diminished growth and became chlorotic 

 in certain calcareous soils, while none showed chlorosis in the noncalca- 

 reous soil. 



Piccioli (36) planted many varieties of chestnuts, together with 

 Sarothamnus, Calluna, and Pteris, on soils with different additions of 

 carbonate of lime. Most plants eventually died on the soil containing 

 12 per cent calcium carbonate. 



Experiments at this Station showed that the mere addition of carbo- 

 nate of lime to soils which normally produced green pineapples (12, 

 p. 20) or rice plants (13, p. 30) caused the soils to produce chlorotic 

 plants. 



The preceding experiments seem to afford direct proof of the conclu- 

 sions derived from field observations and from soil surveys that a chlorosis 

 of some plants is caused by, or associated with, the presence of carbonate 

 of lime in the soil. 



MANNER IN WHICH CARBONATE OF LIME IN THE SOIL INDUCES CHLOROSIS 



IN THE PLANT 



While it is quite generally conceded that carbonate of lime may induce 

 a chlorosis in certain plants, there is a great diversity of ideas regarding 

 the way the chlorosis is brought about. There are several classes of 

 evidence or kinds of data on which conclusions concerning the nature 

 of lime-induced chlorosis are based. These different kinds of evidence 

 will be considered under the following heads: Evidence from analyses 

 of plant ashes, effect of application of iron salts, effect of other lime 

 compounds in inducing chlorosis, and effect of an alkaline reaction in 

 inducing chlorosis. 



RESULTS OP ASH ANALYSES OF PLANTS 



In their work on the chlorosis of the chestnut and maritime pine 

 Fliche and Grandeau (9, 10) analyzed leaves and branches of green 

 and chlorotic trees. They concluded that the chlorosis and diminished 

 growth of the trees on the calcareous soils were the result of an undue 

 absorption of lime and a diminished absorption of other elements, 

 notably potash and iron. 



Schulze (42) analyzed the wood and leaves of green and chlorotic 

 grapevines, 1 determining only lime, magnesia, potash, and soda. Com- 

 pared with the green plants, the chlorotic ones had about one-half as 

 much potash and soda and slightly more lime and magnesia in the ash. 



Biisgen (3) analyzed the broom plants grown by him in calcareous and 

 noncalcareous soils to determine lime and potash. The chlorotic and 



1 Analyses by Mach and Kurmann {31 ) are often quoted in this connection. The results probably have 

 no bearing on this subject, however, as the chlorosis of their specimens seems to have been caused by too 

 much moisture or poor drainage. 



