Fifth International Course and Congress of Hydroponics “Soilless Culture” in Toluca, Mexico

March 30 – April 1, 2006

Introduction

This conference was sponsored by the Hydroponics Association of Mexico. The first conference was held in 1999. Gloria Samperio Ruiz is the President of the Association (photo 1). She has been an enthusiastic supporter of hydroponics for almost 10 years. She has traveled extensively to hydroponic conferences and commercial greenhouses worldwide in her effort to learn about hydroponics. She is the author of three books on hydroponics. The website of the Association is: www.hidroponia.org.mx

The conference was held at the Colegio De Ingenieros Civil Del Estado De Mexico (CICEM) (The College of Civil Engineers of the State of Mexico) in Toluca, Mexico (photos 2, 3). Toluca is located about 50 miles southeast of Mexico City. The climate is arid so has good potential for the greenhouse industry. The conference had excellent attendance by about 700 people (photo 4). People of diversified backgrounds attended the conference, from farmers to investors such as lawyers and business people throughout Mexico where they see an opportunity to grow hydroponically.

Presentations

Mr. Alfredo Delfin from the Universidad Nacional Agraria La Molina, in Lima, Peru presented two papers, the first on Hydroponic Production of Green Forage and the second on Hydroponic Potato Cultivation.

Green forage may be produced within 10 to 15 days from seeding for animals such as cows, horses, pigs, rabbits, etc. He pointed out that such green forage can increase milk production from 10 to 24 percent in milk cows and increase weight in beef cows. The main disadvantage of hydroponic forage is the initial capital cost and the technical nature of managing irrigation, pests and diseases. No substrate is necessary for hydroponic forage as it is grown very similar to sprouts. The seed must be sterilized prior to sowing in trays under mist nozzles for germination.

Disinfect the plastic trays prior to sowing. Spread about 1 kg or 2.2 lbs. in a standard tray 40 cm by 50 cm. Use cereal crops such as corn, wheat, barley, rice, etc. The seed must be surface sterilized and imbibed before spreading into the trays. The seed is irrigated with a nutrient solution.

In his second paper, Mr. Alfredo Delfin explained that potatoes and other tubers can be grown hydroponically using a substrate such as sand or a pure water culture system such as nutrient film technique (NFT). Nutrition and a typical nutrient formulation suitable for potatoes were described. The NFT system can be used to produce seed or mini tubers free of viruses, fungi and bacteria so can be used to produce certified seed potatoes. Between 30 and 35 tubers can be produced per plant.

Mr. Tim Blank, President of Future Growing, spoke of hydroponic cantaloupe and melon production in warm climates such as Florida. The melons are started in rockwool cubes and blocks similar to tomatoes, cucumbers and peppers. Cropping cycles of two crops per year with first planting in early August and the second in mid- to late-January are used in Florida. Substrates such as rockwool, perlite and coconut coir grow melons successfully. Plant spacing is 12 inches within rows and 5 to 6 feet between rows. The plants will grow up to 8 ft. tall. Similar to cucumbers, all laterals are removed up to the 8th node on the main stem. Thereafter, one fruit is permitted to form on each lateral. The plants must be pollinated with bumble bees. If bees are not used you must hand pollinate by placing pollen from male flowers to female flowers.

His second presentation was on lettuce and herb production by aeroponics, NFT, and raft cultures. These water culture systems are particularly suited to growing crops that may be marketed as living produce (plants with roots). This marketing is becoming very popular with consumers of herbs to maintain freshness.

Dr. Lynette Morgan from New Zealand spoke about hydroponic cultivation of strawberries and seedling raising for hydroponic culture. She described how seeds may be sown in sterile substrates such as rockwool or oasis cubes, small pots or compact cell trays filled with inert media of peatlite mix or vermiculite. All these products should be well watered before sowing. She spoke of germination conditions, nutrition, and disease control. She cautioned growers to be careful not to damage roots or stems of seedlings during transplanting as that will predispose them to fungal disease infection. Larger crops like tomatoes, cucumbers and peppers must be transplanted from the seedling cubes to blocks before the second transplant to the greenhouse production area.

The second presentation by Dr. Lynette Morgan was on hydroponic culture of strawberries. Some requirements for growing strawberries include selection of the right cultivar, pre-treatment of runners before planting and maintaining the right environmental conditions for good fruit production. She described a number of cultivars and the growing of strawberries in NFT. A method of propagating plants from runners for later growing in NFT was outlined. Cultural techniques, pest and disease management and harvesting methods were presented.

Dr. Tom Papadopoulos of the Agriculture and Agri-Food Canada Research Station in Harrow, Ontario, Canada presented a paper on “Raised Gutters and Other Popular Greenhouse Technologies in Canada” and a second one entitled, “Greenhouse Tomato Nutrition and Fertilizer Application Schedules.”

He presented statistics on the Canadian greenhouse industry stating that the vegetable component of it is valued at $1.2 billon annually with the main crops being tomatoes (1110 acres), cucumbers (517 acres), sweet peppers (392 acres), and lettuce (37 acres) in 2005. Ontario and British Columbia are the two main greenhouse vegetable production areas. The U.S.A. is the principal market for the products. He said that product quality and safety are the key elements in promoting greenhouse vegetable production. He described some of the main research programs at the Greenhouse and Processing Crops Research Centre in Harrow, Ontario. It focuses on efficient heating systems and energy conservation, supplemental lighting, high-wire systems on raised troughs, carbon dioxide enrichment, irrigation strategies, nutrient solution disinfection in re-circulation systems, alternative energy systems and disease and pest management techniques.

He described the raised troughs (gutters) system of growing plants on a series of raised platforms 30 to 100 cm above the floor. Benefits include increased air movement, uniform crop growth due to less temperature fluctuations, recycling of nutrient solution, convenience for workers and improvement of fruit quality.

In the second presentation he emphasized nutrient requirements and effects. He spoke of the latest technology in water and fertilizer use efficiency by the development of precise and programmable fertilizer injectors which made practical the application of fertigation throughout the cropping season in accordance with the changing needs of the crops. He pointed out that, “The next major step in horticultural production is the accurate application of nutrients and irrigation water according to physiological age and state of the crop, and the prevailing microclimate conditions.” These fertigation systems are controlled by computer feedback systems and the injection of individual compounds to alter the concentrations of various essential elements to better manage the plant growth and resulting productivity.

Two interesting presentations were made by Dr. Ko Welleman of the Netherlands on disinfection of drain water and systems for fertilizer dilution. In the Netherlands and many other countries of Europe water runoff from croplands is restricted. This applies to the greenhouse industry also and as a result more growers are forced to go to recirculation systems of hydroponics. But, such recycling of nutrient solutions comes with risks of contamination. Growers use a number of methods to treat their solutions to prevent diseases. Various methods include: pasteurization, sand filtration, UV radiation and other methods. Dr. Welleman explained how each of these work and what is their effectiveness in preventing contamination. He stated that pasteurization is effective against nematodes, fungi, bacteria and viruses in vegetable crops. Slow sand filters will not prevent viruses, but will reduce to acceptable low levels the presence of Phytopthora, Verticillium and Pythium species as well as nematodes. UV radiation is effective against most organisms depending upon the radiation levels and flow of the water through the radiation tubes at the correct rate, turbulence and thickness of the flow layer. Extra iron chelate will have to be added after the solution passes through the UV sterilizer due to its breakdown by UV light. Ozonation and hydrogen peroxide are also used for disinfection of water.

In his second paper, Dr. Welleman described methods of fertigation and the monitoring of the nutrient solution status using electrical conductivity (EC). He explained the principle of the venturi tube system to inject nutrients into the irrigation water. The use of stock solutions A & B with a mixing tank became more popular with the introduction of rockwool culture. This method has progressed now to the use of liquid fertilizer systems that inject each fertilizer compound separately into the irrigation water. pH control of the nutrient solution was discussed.

Dr. Fritz Schroeder of the Dresden University of Applied Sciences in Dresden, Germany gave two presentations, one on aeroponic cultivation and the other on commercial hydroponic cultivation of poinsettia. He stated that aeroponic systems are the most high-tech type of hydroponics. Upon describing some aeroponic systems he concluded that the main advantages of the system are easy monitoring of the roots, plant nutrition and optimal supply of oxygen to plant roots. Disadvantages include high costs of the systems and fail-safe guards against pump failure. A-frame systems have been developed for leafy crops and rooting of foliage plant cuttings. He concluded that, “Aeroponic systems are used for basic research, education and for special production systems, like an A-frame system for leafy crops.”

Dr. Schroeder outlined hydroponic production of poinsettias in his second talk. He described in detail the use of ebb-and-flow systems for the production of poinsettias in pots on moveable benches.

Dr. Dietmar Schwarz of the Institute of Vegetable and Ornamental Crops at Grobbeeren, Germany, presented very practical information on the preparation of a basic nutrient formulation and nutritional deficiencies of plants. He clearly described with good illustrations the concept of nutritional disorders, symptoms and remedies. He also spoke of nutrient interactions inducing deficiencies, transport problems within the plant and resultant symptoms. He described the effects of pH on plant nutrient uptake. His second presentation covered plant demands on nutrients and water and environmental factors affecting their uptake. Finally, he summarized the calculations of converting a nutrient formulation to actual weights of various compounds in given volumes of solution makeup.


Mr. Carlos Arano, from Argentina, a good friend of mine that I had not seen for almost 30 years, spoke about the management of water in hydroponics and a presentation of how to calculate nutrient formulations using his calculation system available on CD. You can put in vales of a formulation for a specific element and the calculator will determine the weights for a specific volume of solution you wish to prepare. He presented an interesting video on how the human race may suffer due to lack of water on our planet in the future.

Dr. Pedro-Florian Martinez of the Instituto Valenciano de Investigaciones Agarias in Valencia, Spain spoke of substrates for hydroponic culture and production of hydroponic tomatoes. He described physical and chemical properties of various substrates suitable for hydroponics. Tomato production was discussed from sowing seeds to final harvest. He described optimal environmental conditions at various stages of plant growth, training techniques, nutrition and solution management to optimize yields.

Mr. Rogelio Godoy of Koppert Biological Systems, Mexico, illustrated the use of integrated pest management (IPM) in the control of greenhouse pests. He also described the use of bumble bees in pollination of greenhouse tomatoes and peppers. He compared traditional pesticide control with biological control and the resulting fluctuations in pest populations under such control measures. Clearly, much smaller cycles occur under biological control as resistance is not encountered.

Dr. Miguel Gavilan of the Universidad de Almeria, Dept. of Vegetables in Almeria, Spain discussed drip irrigation system in hydroponics and commercial hydroponic cultivation of melons.

Agriculture Engineer, Martin Caldeyro Stajano, of the Asociacion Uruguaya de Hidroponia in Montevideo, Uruguay, spoke of water safety and quality in its use in hydroponics. His second study was on the difference between hydroponic vegetable and traditional vegetable production. This was a very interesting description of how hydroponics is used in place of traditional soil culture in zones of contaminated soils in the Montevideo area. Hydroponics is also being applied in poverty areas to improve social development. He stated that it is magical in opening minds and moving people to be creative. They established a hydroponic lettuce production facility on the roof of a female prison. The prisoners were not only able to improve their nutrition, but also their outlook on life by developing practical skills. With the focus on poor areas, he estimated that about 10% of the families involved in the hydroponic programs go into commercial production and become self-supporting.

Post Conference Tours

Each day during the conference we had lunch in a special tent area accompanied by a Mariachi band (photos 5,6). This gave us further opportunity to speak with fellow presenters as well as the attendees (photo 7).

After the conference was officially closed Saturday night, April 1st, we spent two days on tours. On Saturday there was a post-conference banquet with live music and traditional dances (photo 8). The first tour on Sunday was to the Grutas (Caves) de Cacahuamilpa located about 50 miles south of Toluca (photo 9). These caves were several miles in length and ceilings as high as 60 to 80 feet with many stalactites and stalagmites. The tour guide continually spoke of the appearance of formations as animals and people, including religious figures. These caverns where comparable to sites in the U.S. like Carlsbad Caverns of New Mexico. The bus had to travel on narrow winding roads that sometimes made us sleepy (photo 10).

The second stop that day was at Taxco, a famous town for its silver mines and jewellery. Taxco has a beautiful cathedral and winding streets of typical architecture from the past (photos 11,12). We had lunch at a very nice restaurant before going to some of the jewellery shops (photo 13). We then walked a mile or so to the cathedral (photo 14). In front of the cathedral was a plaza where people were dancing to music (photo 15). We soon joined in for a great time.

The next day, Monday, we went to Teotihuacán to visit the ruins of the ancient Aztec city. Our guide explained details of the Aztec culture and the structures such as the Pyramid of the Sun and the Pyramid of the Moon (photos 16-18). After spending the morning until mid-afternoon we went for lunch at a restaurant on the way to Mexico City. During lunch a band played music and traditional dancers performed (photo 19). After lunch we played a “football” game in the parking lot. That was good for us to become still more acquainted (photo 20).

We concluded the tour that day with a visit to a market in Mexico City. It gave us the final opportunity to buy goods and souvenirs (photos 21, 22). The most difficult time of any conference like this is the final parting from our many friends that we meet, participants, organizers and hydroponic enthusiasts.