The Improvement of Pineapple Soils 
Alfred Warren, Ft. Pierce 
In the improvement of the soil for 
pineapple culture two things should be 
kept in mind; first, the addition of hu¬ 
mus, a very necessary part of any soil for 
any kind of plant production, and sec¬ 
ond, the control of the nematode. 
Humus, although seemingly but scant¬ 
ily supplied on our ridge-land soils, even 
on the virgin land, still plays a greater 
part in the growing of the pineapple than 
most persons believe. It is the humus, 
though meager in quantity on our so- 
called typical pineapple lands as compared 
with that of the rich hammock lands, that 
gives stability to all productive soils and 
this applies equally well to our pineapple 
soils. It helps to retain the moisture, on 
the sandy pineapple lands, which is a very 
important feature; it absorbs and holds 
the fertilizer elements that are applied 
and releases them as the plant needs them; 
it furnishes food and a medium for the 
soil bacteria without which plants could 
make but little growth; and it improves 
the tilth allowing better aeration, bac¬ 
terial action, and other processes that go 
on in the soil for the good of plant 
growth. Humus then is one of the prime 
factors in restoring old pineapple fields 
or in retaining those that are still fairly 
productive. 
Good illustrations of what the lack of 
humus does may be found in perhaps any 
of the pineapple plantations. Parts of a 
field for some reason or other may lie 
fallow and scorch in the sun for a year 
or more, or a path or an alleyway after 
a few years’ of use may be planted to 
pines. Such plantings always stand out 
in glaring contrast to their surrounding 
plantings by their stunted growth, due to 
lack of humus and bacterial life. 
Next in importance in the improvement 
of the soil comes the nematode control. 
The scientists, among whom may be men¬ 
tioned Dr. C. D. Sherbakoff and Messrs. 
J. R. Winston and H. R. Fulton, who 
have given the pineapple problem a great 
deal of thought and attention for the past 
number of years and who are still carry¬ 
ing on experiments in St. Lucie county, 
are still of the opinion that the nematode 
is one of the chief factors, if not the 
chief one, in bringing about the so-called 
pineapple wilt. 
In the summer of 1919 Dr. Sherbakoff 
started some very interesting experiments 
with the view to either prove or disprove 
the nematode theory. Briefly his line of 
attack was sterilization of the soil with 
steam, carbon bisulfid, and formalde¬ 
hyde. In addition to these soil steriliza¬ 
tion experiments other very interesting 
and important test plots were started to 
show the value of selecting strong 
healthy slips versus poor slips; also the 
94 
