8 
INVESTIGATIONS OF PINEAPPLE SOILS. 
CHEMICAL SURVEY OF THE PINEAPPLE SOILS OF PORTO RICO. 
The individual cases where chlorotic pineapples were found are 
described below. The analysis of the soil is given in each case, 
together with that of adjacent areas where pineapples grow well. 
The samples were all taken from the first 8 inches of soil, as in this 
part of the soil practically all the pineapple roots are found. The 
analyses were made by digestion with hydrochloric acid of specific 
gravity 1.115 according to the official methods of the Association of 
Official Agricultural Chemists. The carbon dioxid was determined 
by absorption and from this the percentage of calctum carbonate 
calculated. This does not give a strictly accurate determination 
of the lime present as carbonate, inasmuch as it fails to distinguish 
between calcium and magnesium carbonate. For the purpose, 
however, the method suffices. The oxids of lime and magnesia were 
of course exactly determined in the acid digestion. 
All of the following samples were tested for water soluble alkaline 
salts and chlorids, but none was found present. The alkaline reaction 
of certain of the soils is due to the presence of the carbonates of lime 
and magnesium. 
SOIL SURVEY I. 
Plantation (Isla Verde) of Mr. Noble, about 5 miles east of San- 
turce, P. R.: Here there were 10 acres of Red Spanish pineapples 
on a loose, well-drained, gray sand, a few hundred yards from the sea. 
The surrounding vegetation consisted of icacos, Santa Maria, roble, 
and leguminous weeds and low growing bushes. In 9 or 10 months 
the plants had all become chlorotic with the exception of a 2-acre 
patch at one corner of the field and a few scattered individuals. The 
few isolated plants later lost their color, while in the 2-acre patch 
they did not lose their green color up to the time of fruiting and 
produced fruit of sizes 18, 24, and 36 at the rate of 300 boxes per acre. 
The plants were fertilized at various times with a complete pineapple 
fertilizer. 
A year after planting, about 6 acres of chlorotic plants were taken 
up and set out in a field a quarter of a mile farther inland on a reddish 
sandy soil, of finer texture than that of the original field. The plants 
soon recovered their normal green color and have continued to grow 
well without showing any chlorosis. 
Below are given the soil analyses. Samples 101 and 102 were 
taken from patches where the plants became chlorotic; No. 79 is the 
subsoil beneath chlorotic plants; No. 132 is from the corner of the 
field where the chlorosis failed to appear; No. 152 is a sample from 
the field to which the plants were transplanted with a complete 
recovery. 
[Bull. 11] 
