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.

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

The 4^th 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.

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.

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 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)