45 
Pineapple plantings on calcareous soils should be abandoned and 
the land planted to lime-loving crops. 
In curing the chlorosis, fertilizers were ineffective, but treatment of 
the leaves with solutions of iron salts or crystals of ferrous sulphate 
applied to the roots was effective and induced a normal growth. 
This treatment does not appear to be commercially feasible. 
The chlorosis is not caused by an organic disease, but is the result 
of a disturbance in the mineral nutrition of the plant induced by the 
calcareous character of the soil. 
It is neither the mere alkalinity of calcareous soils nor the large 
amount of assimilable lime that -causes this disturbance, but the 
combined action of the two properties. 
The disturbance in the mineral nutrition of the plant, or the primary 
cause of the chlorosis, seems to be the lack of iron in the ash or the 
small amount of iron in the presenée of a large amount of lime. A 
mere high percentage of lime in the ash does not induce chlorosis. 
Chlorotic leaves are lower in nitrogen and oxidizing enzyms than 
green leaves, due, probably, to the degeneration induced by the lack 
of iron. 
Strong light increases the chlorosis by the more rapid destruction 
of the chlorophyll. 
ACKNOWLEDGMENT. 
The greater part of the analytical work detailed in this bulletin was 
performed by Mr. W. C. Taylor. 
Thanks are due to various planters who kindly sent soil and plants 
necessary for the work, and to Mr. Lucas Valdivieso for 15 tons of 
limestone used in the experiments. 
[Bull. 11] 
O 
