Vegetarian Newsletter

A Vegetable Crops Extension Publication
University of Florida
Institute of Food and Agricultural Sciences
Cooperative Extension Service

Vegetarian 00-08
August 2000

WB01645_.gif (935 bytes)Index Page

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WB01647_.gif (256 bytes) VEGETABLE CROPS CALENDAR

WB01647a.gif (256 bytes) COMMERCIAL VEGETABLES

WB01647b.gif (256 bytes) VEGETABLE GARDENING   (No article this month)

List of Extension Vegetable Crops Specialists

(Note: Anyone is free to use the information in this newsletter. Whenever possible, please give credit to the authors. The purpose of trade names in this publication is solely for the purpose of providing information and does not necessarily constitute a recommendation of the product.)

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Agritech Educational Session and Trade Show - August 29-30. Four Points Sheraton (just down from Florida state fairgrounds) Tampa, FL. Contact: Erin Best at 813-752-6822.
Tomato Institute - September 6. For more information, contact Charlie Vavrina at 941-658-3400.
Florida Association of Extension Professionals 2000 Professional Improvement Meeting & Administrative Conference - September 11-15, Hutchinson Island, Marriott and Marion, Stuart, FL http://extension.ifas.ufl.edu for registration form and hotel information.
The FL-107 Design Team will meet during breakfast (September 15, 7:00 - 9:00 AM) at the Florida Agriculture Extension Professionals Meeting. Check out this web site for more information. http://district1.extension.ifas.ufl.edu/FAEP2000/faep_administrative_session%205-04-00.htm   Contact: Steve Sargent
Florida Agricultural Conference and Trade Show (FACTS) - September 26-27. Civic Center, Lakeland, FL. Contact Elizabeth Lamb at 561-468-3922.
2000 FACTS Meeting, Florida Postharvest Horticulture Institute - September 26-27
This year’s theme: "Maximizing Produce Quality through Effective Cooling". Cosponsored by: Horticultural Sciences Department, Cooperative Extension Service, University of Florida and the Florida Fruit and Vegetable Association. Contact Steve Sargent at 352-392-1928 x215.
Leadership in Vegetables (LIV) South Florida (southern region FL 107) - November 2 ,10:00 AM - 4:00 PM, Immokalee, FL. Contact Charlie Vavrina at 941-658-3400.

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New Specialist in Horticultural Sciences Department in Gainesville

Hello everybody! This issue of the Vegetarian provides me with an opportunity to introduce myself officially to all those I have not met yet. My name is Eric Simonne. My accent will tell you that I am not from here. That’s because before joining the UF Horticultural Sciences Department, I was an Extension specialist in vegetable crops at Auburn University in Alabama. There, for six years (three years as post-doc and three years on tenure-track), I ran the vegetable variety trial program and conducted research in the area of irrigation scheduling and nutrient management for vegetables (1994-2000). With the help of a Ph.D. candidate, we also conducted deer feeding damage control on ornamental and vegetable crops and managed a captive deer herd.

The other reason why I may talk funny is because I was born and raised in Toulouse, France. There, I got the equivalent of a Master’s Degree in Plant Nutrition in 1988 from an engineering school (the Ecole Nationale Superieure Agronomique de Toulouse). After that, I served one mandatory year in the army. In 1990, Drs. Harry Mills and Doyle Smittle from the University of Georgia became my advisors for my Ph.D. studies. The title of my dissertation was ‘Scheduling irrigation for turnip greens [Brassica rapa(L.)]’. After graduating in 1993, I became laboratory manager and QA/QC manager at Macro-Micro International, a private soil, plant, and media analytical laboratory. In 1994, I joined the Department of Horticulture at Auburn University.

I’ve already been a Gator for three months. It’s exciting to be in Florida. I am looking forward to meeting and working with all of you with interest in vegetable production.

(Simonne, Vegetarian 00-08)

2000 FACTS Meeting
FLORIDA POSTHARVEST HORTICULTURE INSTITUTE
September 26-27

This year’s theme: "Maximizing Produce Quality through Effective Cooling"
Cosponsored by: Horticultural Sciences Department, Cooperative Extension Service, University of Florida and the Florida Fruit and Vegetable Association

Beginning this year, the Florida Postharvest Horticulture Institute will be offered in conjunction with the FACTS meeting. This program is in its tenth year and is designed for produce industry professionals, educators and students involved in such diverse areas as field and packinghouse management, import/export, product sales, wholesaling and retailing.

As in previous years, the Institute will continue to address timely topics related to maintaining postharvest quality of fruit and vegetable crops during shipping to domestic and export markets. This year’s Institute will feature leading experts presenting the latest practical information on cooling operations and the cold chain, including principles, methods and techniques developed by University of Florida postharvest research projects. The information will be directed to applications for small, medium and large operations. Demonstrations by related companies are also planned for the Exhibit Hall.

Institute Coordinator: Dr. Steven A. Sargent, Extension Postharvest Specialist, Horticultural Sciences Department, University of Florida, Gainesville

e -mail: sasa@gnv.ifas.ufl.edu, tel. (352) 392-1928, ext. 215, VISIT OUR WEB SITE AT: www.hos.ufl.edu

(Sargent, Vegetarian 00-08)

Hot Water Brushing Treatment Demonstrated at the
International Postharvest Meetings in Israel

The 4th International Conference on Postharvest Science, Postharvest 2000, met in Jerusalem, Israel this spring with over 400 researchers and industry leaders from 40 countries meeting to discuss the latest postharvest research and industry trends. The meetings included over three days of presentations, two poster sessions and a mid-conference tour visiting different production areas, research sites and commercial postharvest facilities. Topics were diverse, covering sensor technology and non-destructive quality assessment, preharvest effects on postharvest behavior, alternatives to chemical decay control, quarantine issues, molecular approaches to improving postharvest quality, practices and technology to improve quality and shelf life of fresh-cut produce, effects of plant growth regulators and inhibitors (e.g. 1-MCP), and many other topics. The next international postharvest conference will take place in Verona, Italy in 2004.

While most of the presentations and posters were excellent, among those potentially applicable to Florida’s vegetable industry were a series discussing a hot water brushing system (Fig. 1) developed by Dr. Elazar Fallik and his colleagues at the Volcani Center in Israel. The treatment was originally developed in 1996 to clean the calyx area of bell peppers (Fig. 2) for export to Europe (Fallik et al., 1996; 1999). During the treatment, product is first washed on a brush bed with potable water at about room temperature, and then washed on another brush bed sprayed with heated water (122 to 158 oF). Commodities are usually in contact with the hot water for between 10 to 30 seconds depending on the commodity and growing conditions (e.g. field vs. greenhouse grown). In Israel, this system has been commercially adopted for a number of commodities including sweet bell peppers, tomatoes, melons, sweet corn, organically-grown citrus, mangoes, kumquats and litchi.

Image2.gif (69978 bytes) Figure 1. Research-scale, hot water brush system developed in Israel.

Figure 2. Before (left) and after (right) washing with the hot water brush system.

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Besides its ability to remove dirt from commodities, the equipment has also been shown to reduce surface microorganism populations, resulting in up to a 4-log reduction (only 0.01% of the microbes left after the treatment). Washing produce with water alone can result in up to a 2-log reduction. Reduced microbial populations result in less decay during transport, storage and retailing and may also play an important role in meeting buyer food safety requirements. For citrus, not only does the treatment reduce decay on fruit inoculated with Penicillium digitatum before treatment, but also when fruits were inoculated 1 to 3 day after the heat treatment (up to 95 % less decay than untreated fruit). Thus, defensive mechanisms were induced within the fruit to inhibit the growth of decay-causing organisms. The treatment also re-deposits natural surface wax over microscopic cracks and openings (stomates), reducing water loss and entry routs for pathogenic fungi. Thus, it may be particularly useful for product sold organically. Heat treatments in general have been shown to reduce chilling injury (CI) of chilling-sensitive crops and such resistance to CI has also been induced in product cleaned with this system.

This is one of many technologies that were presented at the meetings that should be tested under Florida conditions to determine efficacy. Plans are underway by USDA and UF IFAS scientists to obtain a system for testing in Florida.

Literature Cited:

Fallik, E., S. Grinberg, S. Alkalai, O. Yekutieli, A. Wiseblum, R. Regev, H. Beres, and E. Bar-Lev. 1996. A unique method for simultaneously cleaning and disinfecting sweet pepper using hot water wash and brushes (in Hebrew with English summary). Gan Sadeh Vameshek 10, 38-42.

Fallik, E., S. Grinberg, S. Alkalai, O. Yekutieli, A. Wiseblum, R. Regev, H. Beres, and E. Bar-Lev. 1999. A unique rapid hot water treatment to improve storage quality of sweet pepper. Postharvest Biol. and Technol. 15:25-32.

(Ritenour, Vegetarian 00-08)

Calcareous Soils in Florida

Calcareous soils are defined by the Soil Science Society of America (1996) as soils containing sufficient free calcium carbonate (CaCO3) and other carbonates to effervesce visibly or audibly when treated with cold 0.1M HCl.

Calcareous soils are found throughout Florida. Some were formed naturally, while others were developed through land preparation. Various types of limestone (CaCO3) underlie all of peninsular Florida. The surface soils overlying the limestone are either acidic or calcareous. Often deep acidic sandy or clay surface soils overcome the influence of limestone bedrock. Nevertheless, land preparation such as trenching, bedding, deep plowing, etc. can bring calcareous material to the surface. Liming heavily is a common practice to create calcareous soils. In addition soils can be made calcareous through irrigation with CaCO3-saturated water. Calcareous soils in south Florida are formed often from calcareous materials being deposited on limestone, or by mechanically crushing outcroppings of limestone.

Calcareous soils usually contain from 3% to 94% CaCO3 equivalent. The pH values of calcareous soils are greater than 7, and in the range of 7.4-8.4. Textures of calcareous soils can be sandy, loamy or gravelly. Soil depths also range from less than five inches to several feet. These soils are important for production of vegetable, fruit, and ornamental plants in Florida. Over 85% of Florida's tropical fruits are grown on calcareous soils in southern part of the peninsula. However, careful management of nutrients is critically important in the successful production of crops on calcareous soils.

Acidification of calcareous soils: Growers often ask whether they can use soil acidulents such as elemental sulfur (S), sulfuric acid, triosulfate salts, etc. To date, research data have not been developed to establish beneficial effects of application of any acidified products on calcareous soils in Florida. However there is some evidence that addition of acid to groundwater high in bicarbonate is beneficial to plant growth.

Nitrogen (N): Crops grown in calcareous soils often require applying more N fertilizers than in acidic soils. The loss of nitrogen through the volatilization of ammonia is significant for ammonium N fertilizer applied on calcareous soils. Ammonium N fertilizer should be incorporated or introduced into the soil through irrigation. Nitrate N fertilizer is readily leached through sandy or gravelly calcareous soils as a result of over-irrigation or heavy rainfall.

Phosphorus (P): Phosphorous fertilizers applied in calcareous soils are fixed by calcium carbonate (calcite) through adsorption and precipitation. Consequently, the availability of P in calcareous soils is relatively low. However, repeated applications of large amounts of P fertilizer results the accumulation of P in most cultivated calcareous soils. Accumulated P is slowly released into the soil solution to become available to plant roots. This residual P should be considered when growers make fertilizer application decisions for the following crop.

Potassium (K): Potassium deficiency is not common for crops grown in calcareous soils in Florida. However, K is readily leached out the root zone in sandy or gravelly soils. Application of sufficient K fertilizer is important for crop production.

Magnesium (Mg): Although Mg concentrations in calcareous soils are not low, crops grown on calcareous soils often show Mg deficiency. The high calcium concentrations in calcareous soils suppress Mg uptake into plants and translocation from roots to the upper plant parts. Magnesium can be applied as a dry fertilizer or as a foliar application.

Iron (Fe): Iron chlorosis is the most frequent nutritional disorder encountered in crops grown on calcareous soils. Inorganic forms of Fe in calcareous soils are largely or almost totally unavailable for plant uptake. High concentrations of bicarbonate in soil solution can prevent Fe uptake by the plant and translocation within the plant. Most fruit crops are susceptible to Fe deficiency. Chelated Fe (Fe-EDDHA) is commonly used for fruit trees. Most of the vegetable crops commonly grown on calcareous soils in Florida were selected to good adaptation to high pH soils. Thus, they generally do not suffer from Fe deficiency. Iron-efficient crops may release organic acids from their roots to neutralize the bicarbonate and to mobilize soil Fe, or these plants may possess high Fe-reductase activity, or other superior physiological and biochemical characteristics. Foliar applications of chelated Fe or of ferrous sulfate are commonly practiced to improve the nutrition of both fruit and vegetable crops.

Zinc (Zn) and Manganese (Mn): The solubilities and availabilities of Zn and Mn are very low in calcareous soils. However most vegetable crops have the ability to take up sufficient quantities of both Zn and Mn. Application of fungicides containing Zn and Mn also provides available Zn and Mn to plants. Nevertheless, deficiencies of Zn and Mn are very common in crops grown on calcareous soils. Foliar applications or fertigation of Zn and Mn fertilizers can effectively correct these deficiencies.

(Li, Vegetarian 00-08)

Sweet Onion Variety Trial, Spring 2000

Sweet (short-day) onions are a relatively minor crop in Florida. Production, however exists as both dry bulbs (mature) and green tops (immature). Scattered production exists throughout the state. One of the biggest deterrents for increased production is from competition from established markets from the south Texas and south Georgia areas. However, the potential exists for expanded production, especially in the areas of local sales and direct marketing.

The objective of this trial was to evaluate the performance of sweet onion varieties under north Florida conditions.

The transplants for this trial were produced from field beds at the NFREC, Quincy. Thirty one entries were seeded on 4 Oct 1999. Seeds were planted at rate of about 30 seeds per ft into rows spaced 12 inches apart. Preplant fertilization of seedbeds was 30-40-40lbs/a of N-P2O5-K2O. Dacthal 75 W at 9 lbs ai/a was applied over the top after seeding. Seedbeds were top dressed twice with 34 lbs N/a as ammonium nitrate. Entries were transplanted into the production field on 16 Dec 1999. Soil type was an Orangeburg loamy fine sand. Preplant fertilization was 60-80-80 lbs/a of N-P2O5-K2O. Production scheme was 3 rows spaced 18 inches apart under a 6-ft tractor and in-row spacing was 5 inches (52,270 plants/a). Plot length was 25 feet. Design was a randomized complete block with 4 replications. Goal 2XL at 0.5 lbs ai/a was applied on soil surface before transplanting and Dacthal 75 W at 9 lbs ai/a was applied over the top after transplanting. Nitrogen was applied twice during the season at 50 lbs N/a each time. One top dressing of K2O as KCl at 60 lbs/a was made during the season. Registered pesticides were applied as needed to control pests.

Entries were harvested as they matured, where mature is defined as when about 25% of the tops of an entry had fallen down naturally in all 4 replications. Bulbs were lifted, allowed to dry for a few hours and tops and roots removed. Bulbs were then placed in bushel baskets and dried for 72 hours at 100o F in large drying rooms. After drying time was complete, onions were removed, allowed to cool down and graded. Grading consisted of discarding culls (small onions, splits, off color and decayed) and sizing into medium (1.5-2 inches), large (2-3 inches) and jumbo (>3 inches) categories. Bulbs were then weighed and counted.

Harvest occurred from the period of 25 April to 16 May. Total yields ranged from 713 50 lb bags/a for ‘SSC 6361’ to 253 50 lb bags/a for ‘DPSX 1043’. No other entry produced yields as high as ‘SSC 6361’ which was also the highest yielding entry in 1999 trials. Yields were lower in 2000 than in 1999 due to very dry conditions during the production season even though overhead irrigation was used. Foliar diseases became a problem because of the frequent applications of irrigation water, especially with the later entries. ‘SSC 6361’ produced the largest bulb at 9.1 oz and ‘DPSX 1043’ produced the smallest at 4.2 oz. Percent marketable bulbs ranged from a low of 72.2% for ‘Centaur’ to a high of 99.7% for ‘Sweet Success. Days to harvest from transplanting ranged from 131 days to 152 days. Percent bolting level was very low (<1%) for all entries.

Table 1. Onion variety trial results for Spring 2000. NFREC, Quincy, FL

Marketable Yield
(50 lb sacks/A)

Entry

Source

Large

Jumbo

Total

Percent Marketable

Bulb Wt
(oz)

Days to Harvest from Transplant

SSC 6361

Shamrock

97 i-kz

599 a

713 a

94.9 ab

9.1 a

144 c

DPSX 1029

D. Palmer

117 g-j

496 bc

629 b

97.3 a

8.2 b

152 a

Evita

Shamrock

81 jk

542 ab

626 bc

91.6 ab

8.4 b

152 a

SSC 6372

Shamrock

128 g-i

439 cd

576 b-d

98.3 a

7.3 c

139 f

SSC 6371

Shamrock

107 h-k

455 cd

569 cd

96.6 a

7.2 c

138 g

SSC 6436

Shamrock

146 f-h

394 d-f

557 de

97.5 a

7.0 c-e

138 g

Pegasus

Asgrow

109 g-k

402 de

519 d-f

93.8 ab

6.9 c-e

147 b

Chula Vista

Petoseed

144 f-h

329 e-g

505 e-g

96.3 a

6.9 c-e

152 a

Big Pete

D. Palmer

247 ab

216 i-m

504 e-g

97.6 a

6.5 d-g

138 g

Georgia Pride

Shamrock

76 k

409 de

496 fg

91.3 ab

6.9 c-e

131 h

Rio Bravo

Rio Colorado

177 d-f

291 g-j

487 f-h

99.5 a

6.2 f-i

140 e

Sweet Success

Sunseeds

141 f-h

328 e-g

480 f-i

99.7 a

6.4 e-h

140 e

Linda Vista

Petoseed

144 f-h

301 g-i

477 f-j

96.7 a

6.9 c-e

152 a

RCS 1027

Rio Colorado

199 cd

254 g-k

470 f-j

98.3 a

6.1 g-i

140 e

Granex 33

Asgrow

213 b-d

225 i-m

458 f-k

99.2 a

5.9 g-i

140 e

Timon

D. Palmer

181 d-f

250 g-k

457 f-k

92.9 ab

6.7 c-f

144 c

PX 7092

Petoseed

172 d-f

258 g-k

452 g-k

95.4 a

5.6 ij

144 c

RCS 1919

Rio Colorado

235 a-c

183 k-m

449 g-k

99.1 a

5.5 i-k

138 g

XP 6995

Asgrow

178 d-f

252 g-k

448 g-k

96.0 a

6.0 g-i

144 c

Equanex

Petoseed

182 d-f

230 i-m

431 h-l

92.4 ab

5.8 g-i

144 c

DPSX 1041

D. Palmer

255 a

120 no

423 h-m

96.9 a

5.7 h-j

138 g

Mr. Max

Rio Colorado

150 e-g

247 g-k

420 i-m

98.5 a

5.5 i-k

139 f

Centaur

Asgrow

88 i-k

319 f-h

416 i-n

72.0 cd

7.1 cd

147 b

Yellow Granex Imp.

Sunseeds

145 f-h

238 h-l

413 j-n

97.8 a

5.5 i-k

144 c

Savannah Sweet

Petoseed

174 d-f

209 j-m

401 k-n

91.3 ab

5.7 h-j

140 e

Sunsweet

Sunseeds

211 b-d

91 op

371 l-o

97.7 a

5.0 kl

144 c

Sweet Melody

Rio Colorado

191 de

149 m-o

367 m-o

98.5 a

5.0 kl

141 d

Dessex

Sunseeds

203 cd

126 no

356 no

99.0 a

4.8 l

141 d

Sweet Magnolia

D. Palmer

146 f-h

160 l-o

321 op

65.3 d

6.1 g-i

147 b

SXO 1503

Sunseeds

140 f-h

97 op

288 pq

76.8 c

5.1 j-l

147 b

DPSX 1043

D. Palmer

124 g-i

29 p

253 q

86.1 b

4.2 m

152 a

z Mean separation by Duncan’s multiple range test, 5% level.
Comments: Plant population 65,340 plants/a. Fertilizer applied 160-80-140 lb/a N-P2O5-K2O.

(Olson, Vegetarian 00-08)

Improving Sweet Corn Yields

A new approach to improving stand establishment has been developed by Proseed Technologies, Inc., Blissfield, MI. They have a U.S. patent for enhancing growth characteristics of seeds using ion-electron avalanches. They developed a method and apparatus for treating seeds with self-organized avalanches of electrons providing simultaneous DC and AC current being passed through the seed. Sweet corn, carrot, wheat, corn, soybean, oats, and pepper seeds have shown advantages to being treated.

In 1998, two field trials and a temperature controlled growth room study were conducted to evaluate three electron treatments on sweet corn. The field trials were at Lake Jem in Lake County and Sanford in Seminole County. Both were on an Immokalee fine sand and planted March 25. The maximum temperature for the first week was 86F, and was 90F the second week. No emergence or stand differences were observed under the warm conditions. For Lake Jem, the untreated control produced significantly fewer crates per acre than two of the treatments and was 9.3% lower than the third. There were no observed differences in time of silking, harvest maturity, ear width or length, and plant height at harvest.

The Sanford trial had no differences in emergence or percent stand. A plant growth difference was noticed at the tasseling growth stage, but it was not uniform across the four-row plot or for treatments. The three side applications of fertilizer were measured and hand applied and were suspected to be the problem. In this test, two identical check treatments were employed; one check had the highest yield and was significantly higher than one ion-electron treatment and the other check which was the lowest yield. All other ear and plant characteristics were the same.

Growth room data at 20 and 27C indicated the treatments improved early plant growth through taller plants with greater fresh and dry weights over plants grown from untreated seed. The percent germination was slightly lower (84 vs. 86), but was not a factor.

The field studies were repeated in 1999. The Lake Jem trial was lost to inadequate irrigation to establish the stand and the Sanford trial had variable results most likely due to herbicide carry-over injury.

A third field trial was planted at Hastings, St. Johns County, March 2, 2000. No differences could be found for emergence, percent stand, yield, or any of the other characteristics measured. Again, temperatures were warm to hot.

For sweet corn planted and grown under low temperature stress, the treatments should be of benefit. As usual, more work is needed to establish conditions which the response will be economical for the cost of the treatments.

 (White, Vegetarian, 00-08)


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Extension Vegetable Crops Specialists

Daniel J. Cantliffe
Professor and Chairman, Horticultural Sciences Department
Mark A. Ritenour
Assistant Professor, postharvest

Timothy E. Crocker
Professor, deciduous fruits and nuts, strawberry

Ronald W. Rice
Assistant Professor, nutrition
John Duval
Assistant Professor, strawberry
Steven A. Sargent
Professor, postharvest
Chad Hutchinson
Assistant Professor, vegetable production
Eric Simonne
Assistant Professor and Editor, vegetable nutrition
Elizabeth M. Lamb
Assistant Professor, production
William M. Stall
Professor, weed control
Yuncong Li
Assistant Professor, soils
James M. Stephens
Professor, vegetable gardening
Donald N. Maynard
Professor, varieties
Charles S. Vavrina
Associate Professor, transplants
Stephen M. Olson
Professor, small farms
James M. White
Associate Professor, organic farming


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