96 
FLORIDA STATE HORTICULTURAL SOCIETY 
turned under two or three times a year 
for the past two years than in the plots 
where the grass was left undisturbed dur¬ 
ing the three years previous to planting. 
The explanation for this no doubt is that 
where the field is plowed and a long dry 
hot period follows the bare soil is exposed 
to the hot winds and to the rays of the 
sun which burn out both humus and bac¬ 
terial life. 
On our pineapple ridgeland in St. Lu¬ 
cie county Natal grass has up to date 
found no superior in the way of improv¬ 
ing the soil by adding humus and at the 
same time starving out the nematode. 
Natal grass is drought resistant and will 
make a good stand even in dry weather 
on poor soil once it makes a start. 
To summarize the salient points that 
have been brought out by the experiments 
carried on in St. Lucie county in the 
growing of pineapples the following may 
be mentioned: 
i. Restoration of humus in the soil by 
the growing of some plant or plants re¬ 
sistant to the nematode. The different 
varieties of velvet beans, the iron and 
brabham cowpeas, and the various grass¬ 
es are resistant. So far the forage crop 
that has given the best results is the Na¬ 
tal grass. And so far the best results 
with this grass have been obtained where 
it has been allowed to grow undisturbed 
for two or three years and only plowed 
under just before the planting of the 
pineapples. 
It may be that equally good results 
could be obtained by plowing under each 
successive crop of Natal grass if the 
plowing could be done just before a heavy 
rain or just before the starting out of the 
next grass crop, thus allowing only a very 
short period of time for the soil to lie 
fallow. 
2. The control of the nematode. This 
is but a corollary of the first. By plant¬ 
ing nematode resistant plants to restore 
the humus, the nematode will be con¬ 
trolled at the same time. 
3. A definite rotation of crops. For 
a stable pineapple industry the grower 
should have a definite system of rotation. 
After the fourth or fifth crop of pine9 
the field should be planted to some cover 
crop for one or two years to be plowed 
under. A plantation could be divided off 
into say five different plots, and each plot 
in rotation planted to a cover crop, thus 
maintaining a uniform acreage in pine¬ 
apples year after year. 
4. The selection of slips. Cuban slips 
have given good results wherever plant¬ 
ed. But since it is next to impossible to 
obtain slips from Cuba, the grower should 
pay the closest attention to the selection 
of local slips. Only slips from strong and 
vigorous plants should be taken. By con¬ 
tinuing such a practice in a few years a 
strain more or less resistant to the nema¬ 
tode could be developed. Such a scheme 
should have the co-operation of all the 
growers. 
5. Since the fumigation of the slips 
by hydrocyanic acid gas has proven in 
our experiments to make a decided differ¬ 
ence in the growth of the plants, it would 
be well to continue this practice, at least 
as long as we obtain good results from it, 
or until we learn why fumigation is bene¬ 
ficial. 
