INSTITUTE OF FOOD AND
UNIVERSITY OF FLORIDA
^ j ,
A Vegetable Crops Extension Publication
Vegetable Crops Department 1255 HSPP Cainesville, FL 32611 Telephone 392-2134
June 15, 1989
I. NOTES OF INTEREST
A. Vegetable Crops Calendar.
B. Vavrina New Vegetable Specialist
II. COMMERCIAL VEGETABLES
A. An Incorrect Use of the Soil-Test Index.
B. Fall Tomato Varieties.
II. VEGETABLE GARDENING
A. The Potential Value of CD-ROM in Extending
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I. NOTES OF INTEREST
24-28, 1989. State 4-H
Events 4-H Congress.
(Contact Jim Stephens).
July 30 Aug. 4, 1989. ASHS
Convention, Tulsa, OK.
August 23-25, 1989. Florida
Master Gardener Continued Training
Conference. Reitz Union, University of
Florida, Gainesville. (Contact Kathleen
Ruppert, Ornamental Horticulture).
Vavrina new Vegetable
Dr. Charles S. Vavrina is the new
Extension Vegetable Specialist at the
Southwest Florida Research and
Education Center in Immokalee, Florida.
Dr. Vavrina began with the station on
April 1, 1989. His previous employment
was with the University of Georgia as an
Dr. Vavrina was born and reared
in Englewood, New Jersey. He was later
joined in marriage to Ms. Debi Adcock.
Dr. Vavrina received his PhD from the
University of Georgia in March of 1987
where his major was in Horticulture. He
received his MS from the University of
Connecticut in March of 1975 where his
major was in Plant Science. Dr. Vavrina
received his BS degree from Bethany
College in June of 1971 where his major
was in Zoology. Dr. Vavrina holds
membership with several professional
societies throughout the nation.
Dr. Vavrina's responsibilities in
Immokalee will involve all facets of
vegetable culture and management
production technology from site selection
to harvest. Specific responsibilities will
include statewide recommendations and
assistance for vegetable stand
establishment and transplant house
(Cantliffe, Vegetarian 89-06)
II. COMMERCIAL VEGETABLES
A. An Incorrect Use of the Soil-
Several recent instances indicate
that there is a misconception present
regarding the relation of the soil-test
index value and a resulting fertilizer rate.
I have seen a few situations where
individuals have mathematically converted
the index value into the supposed actual
crop-available nutrient on a per acre basis.
The approach here was to multiply the
index (which is expressed in parts per
million) by a factor of 2 to get pounds per
acre. This is based on the assumption
that there are 2 million pounds of soil in
an acre furrow slice. After performing
the calculations, the resulting figure is
subtracted from the crop nutrient
requirement value to arrive at a fertilizer
rate. Sounds easy, right?
There are two problems with
this approach. One problem is that the
2 million pound aspect is surely not very
accurate. The 2 million pound value is
only an estimate for an "average" soil.
What does your soil really weigh? It can
vary greatly depending on soil texture and
The other problem is a major one.
The bottom line is that the index should
not be mathematically manipulated to
derive a fertilizer rate. The index value
is expressed in ppm only because that is
the amount of nutrient extracted from
the soil sample. We extract with the
Mehlich-I extractant. Other labs use
different extracting solutions and thus
produce different index values. Although
we express the index in terms of soil
concentration, the index must be
interpreted as reflecting "low", "medium",
or "high" nutrient supplying capacity of a
given soil. The index does not indicate
the exact amount of a certain nutrient
that is available to the crop. Therefore,
we can not mathematically manipulate the
index to derive fertilizer rates. The
fertilizer rates must result from the
interpretation of the index. If the index
indicates a soil very low in phosphorus,
then we add the total crop nutrient
requirement for phosphorus as fertilizer.
The exact amount of phosphorus to add is
derived from response data gathered from
experiments that test the response of a
crop to added nutrient on a soil that can
not supply much of the crop nutrient
Do not be misled into thinking
that the soil test index is a bottom-line
magic value upon which we can base
fertilizer calculations. That would be an
inappropriate use of the index and one
that could result in a fertilizer
recommendation that is seriously in error.
(Hochmuth, Vegetarian 89-06)
B. Fall Tomato Varieties.
Fall tomato production has been
on the increase in Florida. This increase
has been brought about by the
introduction of two new tomato varieties
that will set fruit under high night
temperatures (greater than 70F). Most
varieties of fresh market tomatoes
presently available set poorly (puffy fruit)
or not at all when night temperatures rise
about 70F for prolonged periods of time.
The two new recent releases for
fall production include 'Solar Set' (FL
7164) a release from University of Florida
breeder Dr. Jay Scott and 'Heat Wave'
(PSR 39686) from Petoseed's breeding
The vine vigor for both varieties is
similar to 'Duke' or 'FTE 12' but less
than that of 'Sunny'. Both varieties
should be pruned lightly (204 suckers
removed) to prevent top fruit from
In replicated yield trials at the
North Florida Research and Education
Center the early and total yields between
the two were not significantly different
(Table 1). Both varieties produce a high
percentage of large (6x6) and extra large
Marketable Yield (cartons/A)
Early Total fruit weight
Medium Large Ex Large Medium Large Ex Large (oz)
Heat Wave 17az 142a 951a 51a 272a 1182a 6.8a
Solar Set 28a 147a 857a 49a 233a 995a 6.7a
Sunny 9b 37b 446b 27a 131b 627b 6.7a
zMean separation by Duncan's Multiple Range Test, 5% level.
Transplanted July 18, 1988, white plastic, 20 in in-row spacing. Fertilizer applied
200-80-320 lb/A N-PgO2-K20, trickle irrigation. Harvested September 27-October 12,
Seed of both may be in limited supply for fall, 1989 production. 'Solar Set' is available
through Asgrow or Asgrow-Florida dealers and 'Heat Wave' through Petoseed dealers.
(Olson, Vegetarian 89-06)
m. VEGETABLE GARDENING
A. The Potential Value of CD-ROM
in Extending Gardening Information.
It seems to me that Extension
delivery systems have picked up
dramatically in the past 5 years or so,
particularly in the area of electronics.
Most advances have centered around
videos and computers.
Along these lines I was fortunate
to attend a workshop held the last day of
May by the Gainesville CD-ROM group
led by Pierce Jones of the Ag Engineering
Dept. What I and about 40 of my
Extension colleagues (including county
agents) found out was that CD-ROM has
exciting potential for us in Extension,
particularly those of us who work in the
home horticulture arena.
I still don't know much about the
technical aspects of CD-ROM, but in
simple terms it translates to a Compact
Disc, Read Only Memory, which can be
plugged into our computers if we get the
necessary adaptations. Now what makes
it unique and different from the
computerized retrieval systems we already
have on VAX, such as FAIRS, is that CD-
ROM is an independent system. We don't
have to dial up the VAX on the phone;
instead, just pop in a disc. You get a disc
in the mail which contains an
unbelievable storage capacity of factual
information (text) complete with graphics.
The disc is over 5 inches in
diameter, yet can store 250,000 pages of
information; you can retrieve any part of
it almost instantaneously, either for
printing or just viewing.
The hardware and software
required appear to be fairly reasonable
obstacles to overcome both from
standpoint of price and required
equipment. CD-ROM works with most
IBM-PC compatibles, using a CD-ROM
drive, a laser printer and Word Perfect
All of the details of the delivery
system are in the capable hands of the
CD-ROM group, led by Jones. In its
attempt to get this system operational for
us in IFAS Extension, the group is
putting material on the discs as we
specialists prepare it and present it to
While I can speak from only one
specialist's viewpoint, it looks to me that
CD-ROM has vast potential for us in
Extension. I plan to utilize this
opportunity to the fullest extent. Can
you imagine all of the information on
gardening that has been generated by
IFAS located on one simple disc? Right
now it is scattered everywhere. We have
circulars, handbooks, fact sheets, bulletins,
mimeo reports, miscellaneous reports,
conference/seminar notes, and much,
much more, just sitting in files, hidden
Of course it's going to take a lot of
clerical and word processing assistance
(time) to find all this material and
transfer it to the CD-ROM format.
However, with commitment we can start
in that direction.
I do not envision CD-ROM
replacing the printed literature that we
are all so used to having, and still need in
abundance. What it will do is supplement
what is printed, so that county Extension
offices have an alternative.
It's best value appears to be in
providing access to little used, and
therefore out-of-print documents. For
example, selected topics from my old
Vegetarian articles might be useful from
time to time for reference to answer
gardening questions, prepare TV and radio
talks, newsletter articles, and news stories.
CD-ROM should prove extremely
valuable in the 4-H area, where the
publications pinch due to funding
problems is being felt as much as in
agriculture. Several old as well as current
project record books and literature have
fallen by the wayside, not to be reprinted.
However, some counties may need one
occasionally for specialized usage. If on a
CD-ROM, it could be retrieved and
printed by the county for that county
And that last statement leads to
the disadvantages of CD-ROM, the first of
which is printing costs borne by counties.
However, when weighed against the
alternative, which in most instances will
be no publication available, the cost seems
Another glitch to be worked out is
the need to properly identify the origin
and authenticity of the material. In-
house printing at the county level will
have a tendency to print only the meat of
what information is needed, leaving off
authorship, acknowledgements, and other
bits of identity.
Materials for use in the Florida
Master Gardener program are under
transition to the CD-ROM delivery
system. I suspect we will learn much
from this initial trial. As more and more
experience is gained, I am confident we
all will applaud this new and potentially
powerful addition to our arsenal of
(Stephens, Vegetarian 89-06)
Prepared by Extension Vegetable Crops Specialists
Dr. D. J. Cantliffe
Dr. G. J. Hochmuth
Dr. S. M. Olson
Mr. J. M. Stephens
Dr. C. S. Vavrina
Dr. D. D. Gull
Dr. D. N. Maynard
Dr. W. M. Stall
Dr. S. A. Sargent
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