, 1963-08-22
Pages

tanned in Florida and miscellaneous smaller lots of other
varieties intended for use as rootstocks for Valencia orange
nursery trees. This nursery is on good soil, has received sup
Elemental irrigation as needed and the seedlings appear Wig
orous and healthy.
The AIRS group, in company with DR.. Miller and Mr..
Killough, visited small citrus paintings and dooryard citrus
trees in several locations on the island. In General the plant
ings had been neglected and had not had proper management
and the trees were small and in poor condition. Trees grow
ing at high elevations appeared more thrifty than those at low
elevations. The small scale commercial paintings visited were
principally in the west and northwest end Of the island on the
higher elevations where drainage was good and rainfall near
maximum for the islands. The varieties involved were Wash
ington Naval, Valencia types, a few grapefruit, Key and Per-
sian lines and were mostly on sour orange root-stocks, The
paintings were mostly in sod OF native grasses and were show
ing various nutrient deficiencies and moisture stress. Many
of the trees were infested with scale, asphids, white flies and
ether insects as well as infected with various diseases.
Commercial citrus production is generally limited to areas
of the world having temperatures with an average diurnal
range of 800 degrees F. during the growing season, with
a minimum above freezing except for short periods, with
ample but not excessive moisture, without excessively drying
winds, and with suitable soil types. Citrus will grow on a
number of soil types ranging in PHI from 55-85, provided
they have ample drainage, and are not saline or too highly
calcareous.
On the Vicorp land being considered for citrus production,
there at least 4 major handicaps present that make the pro-
jcet highly questionable. These are listed in the order of
their limiting effects. Q Inadequate water supply. () High
calcium deposits in subsoils which prevent citrus from absorb
ing sufficient iron, resulting in chlorosis and poor growth. 90
High cost Of control of insects and diseases. az Hazard Of
wind damage to trees from tropical storms.
~ insufficient wafer supply. The amount of water ne
.cessary for commercial citrus production varies with air tenn
.perature and humidity, soil type, and seasonal distribution.
In medium heavy but well-drained clay base soils and areas
with diurnal tempertures ringing from $3.50 degrees F. and
relative humidity ranging between 50-75 percent, citrus re-
quires a minimum of approximately 40 inches of rainfall
fairly we'll distributed through the year with no long pro-
tracted droughts. In lighter soils with less Water-holding
capacity, more moisture is required. Prolonged wet seasons
on heavy soils limit citrus culture from the standpoint of "wet
feet"
The Vicorp land on St. Croix varies in soil type and has
an annual average rainfall varying from 50 to45 inches but is
subject to periodic drought up to 5 months and fairly regular
annual ones up to 3 months. A 5-month drought would serious
ly damage trees resulting in death to some, whereas lesser
droughts would seriously reduce production.
Supplemental water in the form Of irrigation could over
come this difficulty but only small quantities appear likely
to be available. -Four pounds on the Vicorp property have a
combined capacity of 81-acre feet. The terrain appears sufi-