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Greenhouse Operaion |
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| A piece of the Westland moves to Spain |
During a recent technical meeting in Spain, Douglas Marlow, Grodania's Technical Consultant in North America, had the opportunity to visit the newest vegetable glasshouse located in Alméria, Spain.
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| The Dutch tomato group Action Pearl and their Spanish partners, after several years of planning, have built a modern glass glasshouse amongst the sprawling polythene structures of Alméria. It was a decision that has allowed them to produce quality Aranca-on-the-vine tomatoes year round. The 4 ha Dutch built glasshouse is called 'Greenhouse Treasure' and lies on levelled land that was once a rocky hillside. Construction was completed at the end of August 2001 and an additional 4 ha is planned for 2002. |
The glasshouse viewed from the neighbours property
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The head grower, Sr. Javier del Aquila is extremely very proud of this new project. The 4.75 m (to the gutter) glasshouse is fitted with hanging gutters positioned 60-cm above the ground which collect all run-off as part of a closed irrigation system.
The crop was sown at a local propagator on 10th August and two plants were placed into each of the Grodan®'s DM 6.5 Iberica blocks. The plants were then planted directly onto the Grodan® Expert slabs (20 x 7.5 x 200-cm) on September 8th, 2001. The initial planting density was 3.2 plants/m2. In Week 3, the stem density was increased by 33% to 4.2 stems/m2. Higher densities are planned for next crop in an attempt to further improve the climate in the nursery and at the same time increase the total yield. With 10 plants on a 2-m slab, the substrate volume is a very respectable 9.6 L/m2. This has allowed Sr. del Aquila to develop a sound water management programme tailored to the climatic conditions Alméria.
Two tomato viruses are currently active in the Alméria area. First is Pepino Mosaic Virus (PepMV) and the second is Tomato Yellow Leaf Curl Virus (TYLCV). PepMV is avoided by observing strict hygiene measures similar to those adopted in many Northern European glasshouses. The latter virus is transmitted by the sweet potato white-fly Bemisia tabaci. Biological control of this damaging pest is impossible at the time the crop was planted as the temperatures are too high. Therefore in order to avoid spraying chemicals Action Pearl installed insect screens on all vents to prevent the entry of Bemisia. This has allowed them to follow a 100% biological control programme and use bees for pollination. |
Typically Dutch: hanging gutters, grow-pipe and leafing high up the stem
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Located above the crop are two computer-controlled, movable screens. One is a thermal screen for heat retention during the cold, clear Spanish nights. The other is a shade screen to protect the crop from the intense summer light during the peak of the day. The screens, as is the rest of the climate, are controlled by a state-of-the-art Priva Integro computer.
Besides the state-of-the-art equipment and techniques already described, they are also experimenting with a phytomonitor. This equipment is connected directly to the plant and is able to monitor and measure various plant-growth parameters. Amongst these parameters are fruit growth rate, leaf temperature and stem flux (change in stem diameter throughout the day). Sr. del Aquila commented that this device provides so much information that it is sometimes hard to make sense of it all and relate it to the real growing situation.
Sr. del Aquila and his staff are also working with Grodan®'s hand water content meter (WCM-H) as well as Grodan®'s Continuous Water Content Meter (WCM-C) connected to the Priva computer. In association with these devices, they are working with technicians and advisors from Grodan® Med. to develop a sound water management strategy.
It was very obvious to all of those touring the facility that things can be done differently in Alméria and that we were witnessing the future.
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Insect netting 6mmx6mm is placed on all vents to keep out Bemisia tabaci
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