RELATION OF CALCAREOUS SOILS TO PINEAPPLE 
CHLOROSIS. 
INTRODUCTION. 
HISTORY OF PLANTINGS ON UNSUITABLE SOILS. 
Raising pineapples on a commercial scale is a comparatively new 
but rapidly growing industry in Porto Rico. As more and more land 
is being planted to pineapples it is becoming apparent that all of the 
loose, well-drained soils are not adapted to this crop. On certain 
well-drained soils of good physical condition the pineapple plantings 
have been very unsuccessful. The failure of these plantings has been 
attended by a peculiar “‘ bleaching” or chlorosis! of the plants, in some 
cases so complete that the leaves contain hardly a trace of chlorophyll. 
The investigation detailed in the following pages was undertaken 
for the purpose of discovering the cause of the chlorosis and the failure 
of the crop on these soils. 
The first instance of the plants presenting this peculiar bleached 
appearance on a well-drained soil was noted at Rincon, P. R., by Mr. 
H. C. Henricksen in 1904, and is described in the annual report of this 
station for 1905:? 
In the fall of 1903 about 2 acres were planted at Rincon with the variety Cabezona. 
The plants were reported to be diseased and the field was visited April, 1904, at the 
owner’s request. The plants were found to be of normal size, but the color of the 
leaves was of a light red to pure wax white, about 50 per cent being entirely devoid of 
chlorophyll and less than 15 per cent showing green, the rest red, green, and white 
mixed. The field was located near the ocean, but in no way injured by salt water. 
The soil, which was a beach sand, had recently been cleared of its natural growth, 
consisting mainly of coconut, sea grape, coco plum, a few sour orange trees, and the 
usual tropical shore-line plants. 
Since this case was reported numerous other. instances of pine- 
apples showing the same appearance have been noted. On two 
plantations, of about 10 acres each, the plants became almost uni- 
formly yellowish white and ultimately succumbed. About 60 per 
1 Chlorosis (sometimes called ‘‘icterus,”’ ‘‘ bleaching,” or ‘‘ Gelbsucht’’) is the term applied to that con- 
dition assumed by the leaves of plants when they fail to develop the normal amount of chlorophyll, or 
green coloring matter, i. e., when they are yellowish or white instead of a normal green. Chlorosis, then, 
does not denote a specific disease, but merely a general condition. This condition of chlorosis, however, is 
the result or outward sign of a disease or disturbance in the physiology of the plant. To say that a plant 
is “‘chlorotic,’’ or affected with chlorosis, means merely that its leaves are lacking in chlorophyll; but the 
ehlorosis may have resulted from a bacterial disease, poor drainage, lack of nutriment, or some other cause, 
2 Porto Rico Sta. Rpt. 1905, p. 30. 
[Bull. 11] (5) 
