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| Retractable roof structures; how to profit from the Mediterranean climate | |
| On the 8th September at S.Stefano al Mare (IM), the inauguration of the first Cravo ‘open-roof’ structure in Italy took place at the Az.Agr. Piccirilli di Stefano Carissimi. ‘Modello Piccirilli’ is the name chosen for the first retractable Cravo structures erected in Italy, specially designed for erection on sloping land up to a 10% gradient. The cost per mq lies between that of a greenhouse and that of a poly multi-tunnel. Giancarlo Cassini, Assessore all’Agricultura for Liguria, confirmed that in the rural development plan for 2007-2013, utilizing EU funds, an economic subsidy of up to 80% of the cost will be available to growers in Liguria who purchase this type of structure. He emphasized that Cravo’s ‘Modello Piccirilli’ is not a greenhouse but a mobile protective structure. Consequently the bureaucratic regulations governing the construction of greenhouses (as permanent structures) is avoided. Growers have a new instrument with which to maximize quality associated with open-field production, closing the roof only when necessary. Ordinarily, in the winter conventional greenhouse structures cast too much shade and shut out useful UV light while in the summer excessive ventilation is needed to lower the temperature. He continued, “Growers need to believe in the sector and to invest if they are survive. The region is determined to help create these conditions for all its capable growers by promoting investment in this type of retractable structure thereby reducing the risk and cost to individual growers. Few are currently able to afford such investment. Cravo’s ‘Modello Piccirilli’ will also assist in the objective of improving and reinforcing the production of typical Ligurian crops and making it more competitive”. The ‘Modello Piccirilli’ retractable structure is in not limited to the average and smaller production units typical of Liguria but is highly adapted to large production units in Mediterranean areas. In effect, the ‘Modello Piccirilli’ structure promises to seriously blur the modern distinction between high-tech Holland and low-cost Africa. Production is ‘open air’ for those long periods of high UV Mediterranean sunshine (including those lovely sunny winter days in January!) when high rate transpiration pulls up more water and minerals coupled with a high rate of photosynthesis and stronger plant development. Under the roof in the ‘Modello’ structure is a secondary mobile screen to provide for additional summer shade or winter insulation. In those relatively short periods in a given production cycle of excess heat, cold, rain and hail, the roof and screens are partially or fully closed as is required to protect the crop and yet maintain production parameters as close as possible to achieve an optimum plant stress required for healthy growth and development. Resulting plants are tougher, more resistant to disease, more compact, more floriferous with earlier flowering and faster production times. Insect pests do not like wind, UV light or tougher plant tissue. In trials in Arizona where winter temperatures are very low, rising to 50°C in the summer, the yield of tomatoes (and Capsicum) increased by 130% using Cravo’s ‘Modello Piccirilli’ retractable growing sructures. It is anticipated that the yield in most crops in Mediterranean regions can be increased by 20-30% in comparison to production in ordinary glasshouses or plastic tunnels. The opening and closing mechanism is fully automated and is calibrated according to crop requirements. From an ‘open-roof’ position, the 4000m2 structure at Az. Agr. Piccirilli can be closed in just 2.5 minutes. Cravo’s retractable structures are also extremely resistant to high winds and the covering is contained underneath the supporting metal wires. Cravo structures successfully withstood recent hurricane force winds in the USA (whereas ordinary greenhouses suffered serious damage). It is anticipated that claims in Liguria for damage |
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